Session 4:
Beam Dynamics and Electro-magnetic Fields
SPS Coordinator: Francesco Ruggio, CERN, Geneva
1-163 - COD Correction by Novel Back-leg at the
KEK-PS Booster
Shigeshi Ninomiya (KEK, Ibaraki)
The COD correction is performed by using new driving
system of back-leg windings. Two back-leg coils of the
separate magnets are connected to make a closed
circuit in which the induced voltages of the two
magnets have opposite phases to each other. When the
current source is inserted into the closed loop, the
current drives the two magnets with opposite polarities.
If the pair of magnets is properly selected, the current
effectively corrects the orbit distortion. The selection
rule of the pair is as follows; one is the magnet at the
maximum distortion and the second magnet is that
separated with the betatron phase of -90deg. The
correction system at the KEK-PS Booster reduced the
COD to less than 1/5 of that without correction, and
increased the capture efficiency. The average beam
intensity of our Booster is increased from 2E+12 to
2.6E+12ppp.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
2-166 - Non-linear Evolution of Vortices in
Electrostatic Plasma Lens for High-current Ion
Beam Focusing
Vasyl Maslov, Alexey Goncharov, Vitaly Tretyakov
(NSC/KIPT, Kharkov)
In the plasma lens (PL) for ion beam focusing the
vortices can be excited. In this presentation the
equation describing the vortex has been derived. The
correlation between linear growth rate and nonlinear
one is obtained. The structures of slow and fast vortices
of small and large amplitudes and their dependences on
lens parameters are described. The vortices are excited
in homogeneous plasma by pairs. The non-uniformity
of the electron density leads to the situation when the
vortex - concentration (vortex - hole) goes to area of
larger (smaller) electron density. The radial velocities
of the vortices are calculated. The formation of spiral
distribution of electron density due to electron
reflection by vortex is described. The possibility of
suppression of instability development of collective
field excitation in near wall area of PL due to electron
density increase on radius in this area has been
considered. It has been shown by numerical simulation,
that the aberrations, called by such electron density
distribution on radius, are small. The numerical
simulation is also used for determination of focusing
quality of high-current ion beams by the electrostatic
PL with various parameters. This work is partly
supported by STCU project No. 1596.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
3-202 - Transfer Matrices for the Coupled Space Charge
Dominated Six-dimensional Particle Motion
Davit Kalantaryan, Yuri Lawrent Martirosyan (CANDLE,
Yerevan)
In this paper we present exact analytical solutions for the
particle motion in the six-dimensional phase space taking
into account the space charge forces of fully linear coupled
beam. The transfer matrices for the typical elements of
magnetic lattice, such as drifts, cavities, quadrupole and
dipole magnets have been obtained. The symplectic transfer
matrices are used to develop a tracking program for the
coupled betatron and synchro-betatron motion that enables
the simulation of the tilted beam effects in circular
accelerators.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
4-239 - The Small-gap Undulator Impedance Study
Michael Ivanyan, Vasili Mkrtich Tsakanov (CANDLE,
Yerevan)
The small gap undulator vacuum chamber resistive
impedance model is developed. The vacuum chamber is
considered as equal-radii tubes with the different wall
materials (stainless steel "copper" stainless steel). The
complete impedance was calculated as a sum of tubes and
transitions impedances. The modal expansion method for
transition impedance calculation is presented.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
5-331 - RHIC Optics Measurements at Different
Working Points
Mei Bai, Rama Calaga, Steve Peggs, Thomas Roser, Todd
Satogata (BNL, Upton, Long Island, New York)
Working point scans at RHIC were performed during 2004
to determine the effect on lifetime and luminosity. Linear
optics were measured for different working point tunes by
exciting coherent oscillations with the aid of RHIC AC
dipoles. Two methods to measure the beta functions and
phases are presented and compared: a conventional
technique, and a new method based on singular value
decomposition (SVD). The performance of a 3-bump beta
wave algorithm to identify quadrupole error sources is also
presented.
Work performed under the auspices of the US Department
of Energy
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
6-341 - Tune Survey of Dynamic Apertures for
High-brilliance Optics of the Pohang Light Source
Eun-San Kim (PAL, Pohang)
The PLS storage ring is a 2.5 GeV light source and the
dynamic apertures in a lattice for the low emittance in
the ring have been investigated by a simulation
method. The dynamic apertures that include effects of
machine errors and insertion devices were obtained by
a tune survey in the simulation. It was also shown that
how large are the dynamic aperture compensated after
corrections of a CODs. The betatron tune for the
operation of the high-brilliance lattice are investigated
based on the view point of dynamic apertures obtained
from a tune survey.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
7-347 - Minimum Electron Beamsize of Double and
Triple Bend Lattices
Tae-Yeon Lee, Jinhyuk Choi (PAL, Pohang)
It has been recently popular in light sources to make
insertion straight sections dispersive to achieve lower
emittance. But since the introduced dispersion
contributes to the elctron beam size, the emittance
ceases to be directly related to the brightness. Hence
discussed in this paper is the electron beamsize in
unsertion straights rather than usual beam emittance.
Theoretical minimum beamsize is investigated both for
double and triple bend lattices
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
8-419 - Optimization of Sextupole Strengths in a
Storage Ring for Top-up Operation
Hitoshi Tanaka, Takashi Ohshima, Kouichi Soutome,
Masaru Takao, Hideki Takebe (JASRI/SPring-8,
Hyogo)
In top-up operation of a light source, electron or
positron beams are frequently injected to keep the
stored current constant. Closing an injection bump
orbit is thus critically important not to disturb precise
experiments. However, there are sextupole magnets
inside the injection bump in the SPring-8 storage ring
and the bump never closes all over the bump amplitude
due to the sextupole nonlinearity. To solve the
problem, we proposed a scheme based on minimum
condition for the injection bump leakage. The scheme
only restricts the sextupole strengths within the bump.
Introduction of other sextupole families outside the
bump can enlarge the dynamic aperture (DA) of the
ring with keeping the minimum leakage. To find the
best solution, we optimized the sextupole strengths
changing the number of sextupole family as a
parameter. The simulation shows that addition of two
sextupole families sufficiently enlarges DA. Cabling of
the sextupole magnets was partly changed in the
summer 2003 and the effects of the strength
optimization on the bump leakage, injection efficiency
and
beam lifetime
has
been
investigated
experimentally. We present the obtained results
compared with the simulations.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
9-449 - RF Focusing of Low-Charge-to-Mass-Ratio
Heavy-Ions in a Superconducting Linac
Eduard Sergeevich Masunov, Dmitry Alexandrovich Efimov
(MEPhI, Moscow), Peter Ostroumov (ANL/Phys, Argonne,
Illinois)
A post-accelerator of radioactive ions (RIB linac) must
produce high-quality beams over the full mass range,
including uranium, with high transmission and efficiency
(P.N. Ostroumov and et al., Proc. of the PAC2001, p.
4080.). The initial section of the RIB linac is a low-chargeto-mass-ratio superconducting RF linac which will
accelerate any ion with q/A>=1/66 to ~900 keV/u or higher.
This section of the linac consists of many interdigital
cavities operating at –20 degree synchronous phase
and focusing can be provided by SC solenoids following
each cavity. For the charge-to-mass ratio q/A=1/66 a proper
focusing can be reached with the help of strong SC solenoid
lenses with magnetic fields up to 15 T. These state-of-the-art
solenoids are expensive. A possible lower cost alternative
focusing method based on the combination of low-field SC
solenoids and RF focusing is proposed and discussed in this
paper.
Work supported by the U. S. Department of Energy under
contract W-31-109-ENG-38
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
10-506 - Trajectory Correction Studies for the CNGS
Proton Beam Line
Malika Meddahi, Werner Herr (CERN, Geneva)
The performance of the proposed trajectory correction
scheme for the CNGS proton beam line was checked with
an advanced simulation program. It was first investigated
whether the scheme will be sufficient, and if some
correctors or monitors could be suppressed in order to
reduce the cost. The correction scheme was in particular
tested for the case of faulty correctors or monitors. Possible
critical scenarios were identified, which may not be visible
in a purely statistical analysis. This part of the analysis was
largely based on the experience with trajectory and orbit
correction problems encountered in the SPS and LEP. The
simulation of the trajectory correction procedure was done
using recently developed software.
CERN
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
11-507 - Aperture and Stability Studies for the CNGS
Proton Beam Line
Malika Meddahi, Werner Herr (CERN, Geneva)
The knowledge of the beam stability at the CNGS target is
of great importance, both for the neutrino yield and for
target rod resistance against non-symmetric beam impact.
Therefore, simulating expected imperfections of the beam
line elements and possible injection errors into the CNGS
proton beam line, the beam spot stability at the target was
investigated. Moreover, the mechanical aperture of the
CNGS proton beam line was simulated and the results
confirmed that the aperture is tight but sufficient.
CERN
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
12-540 - Optimization of Low Emittance Lattices
for PETRA III
Winfried Decking, Klaus Balewski (DESY, Hamburg)
The reconstruction of the existing 2.3 km long storage
ring PETRA II into a 3rd generation synchrotron light
source (PETRA III) calls for an horizontal emittance of
1 nm rad. In addition the on- and off-momentum
dynamic acceptance should be large to ensure
sufficient injection efficiency and beam lifetime. We
present three different types of lattices for the arcs of
PETRA: a so-called TME lattice and a FODO lattice
which both are newly designed to reach the specified
emittance and the present FODO lattice with damping
wigglers. The different lattice types have been
compared through tracking calculations, including
wiggler nonlinearities. Only the relaxed FODO lattice
with damping wigglers meets the acceptance goals.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
13-590 - Closed Orbit Correction and Orbit
Stabilisation Scheme for the 6 GEV Synchrotron
Light Source PETRA III
Gajendra Kumar Sahoo, Klaus Balewski, Winfried
Decking, Yongjun Li (DESY, Hamburg)
PETRA III is a 6 GeV synchrotron light source being
reconstructed out of the existing storage ring PETRA
II. It will have a horizontal beam emittance of 1nm.rad
and a 1% emittance ratio. Since the vertical beam sizes
are ~5?10 micron in the low gap undulators sections
the beam position stability requirement in the vertical
plane is between 0.5 and 1 micron whereas the stability
requirement in the horizontal plane is more relaxed. In
this paper determination of golden orbit in the presence
of magnetic field errors and magnet misalignments and
correction of vertical spurious dispersion is discussed.
A scheme of slow and fast orbit correction using the
SVD algorithm has been developed. The distribution of
monitors and the location of slow and fast correctors
are reported. Estimations of the parameters of the fast
orbit feedback have been derived from present
measurements on PETRA II.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
14-627 - Beam Quality Preservation in the CERN
PS-SPS Complex
Gianluigi Arduini (CERN, Geneva)
The LHC will require beams of unprecedented
transverse and longitudinal brightness. Their
production imposes tight constraints on the emittance
growth in each element of the LHC injector chain,
namely the PS-SPS Accelerator Complex. The
problems encountered at the different stages of the
acceleration in the complex span a wide range of topics,
such as injection matching, RF gymnastics, space charge,
transverse and longitudinal single- and coupled-bunch
instabilities, and electron cloud effects. The measurement
techniques developed and applied to identify and study the
various sources of emittance dilution to the high precision
required for the LHC beams and the solutions found to
control such phenomena are illustrated.
AB Division, CERN, Geneva, Switzerland
Type of presentation requested: This is an Invited Oral
Presentation
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
15-648 - Transverse Optics Improvements for RHIC
Run 4
Johannes Van Zeijts (BNL, Upton, Long Island, New York)
The magnetic settings in RHIC are driven by an online
model, and the quality of the resulting lattice functions
depend on the correctness of the settings, including
knowledge of the magnet transfer-functions. Here we first
present the different inputs into the online model, including
dipole sextupole compenents, used to set tunes and
chromaticities along the ramp. Next, based on an analysis of
measured tunes and chromaticities along the fy03 polarized
proton ramp, we present predictions for quadrupole transferfunction changes. The changes are implemented for the fy04
Au ramp, and we show the improved model agreement for
tunes, and chromaticities along the ramp, and measured
transverse phase-advance at store. We also describe model
improvements for derived observables like the quality of
transverse bump closure and observed luminosity ratios
between individual interaction points.
Work supported by U.S. DOE under contract No DE-AC0298CH10886
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
16-653 - Beam Invarients for Diagnostics
Viatcheslav V. Danilov, Alexander V. Aleksandrov
(ORNL/SNS, Oak Ridge, Tennessee)
This paper deals with some measurable quantities of beams
preserved under symplectic transformations. General beam
distributions have no determined area, and rms quantities of
the beam do not provide invariants in general nonlinear
case. It is shown, though, that in the 1D case there exist
some integral and local invariants, directly linked to
Liouville's theorem. Beam invariants, related to general
properties of symplectic transformations, are also found and
presented for 2D and 3D cases. If measured at different
locations, they can tell whether the transformation is
symplectic or there exists diffusion, friction, or other nonHamiltonian dynamic processes in the beam.
Research sponsored by UT-Batelle, LLC, under contract no.
DE-AC05-00OR22725 for the U.S. Department of Energy
SNS is a partnership of six national laboratories: Argonne,
Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos,
and Oak Ridge
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
17-729 - The Project of the Emittances Reduction in
the Siberia-2 Storage Ring of KURCHATOV
Center of SR
Vladimir Korchuganov, Sergey Sinyatkin (BINP,
Novosibirsk), Alexandre Valentinov, Yury Yupinov
(RRC Kurchatov Institute, Moscow)
The 2.5 GeV dedicated SR source Siberia-2 works with
an electron beam having horizontal emittance 98 nmrad. In the report the results of theoretical development
of variants of magnetic optics with small emittances
are presented. The calculations show, firstly, an
opportunity exists to achieve a 66 nm-rad horizontal
emittance at the expense of optic change only. In this
case the arrangement of magnetic elements is not
changed and the achromatic bends are kept. Secondly,
in a case with not zero dispersion in all straight
sections of Siberia - 2, optical structure with 17 nm-rad
emittance (at 2.5 GeV) it seems quite achievable with
the existing opportunities of changing the magnetic
elements parameters. In this case the injection scheme
demands the installation of one additional kicker for
the matching of the pre-kick and kick. The results of
experimental testing of the 66nm-rad structure will also
be given in the report.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
18-741 - Evolution of Optical Asymmetries in the
Elettra Storage Ring
Fatma Iazzourene, Simone Di Mitri, Emanuel
Karantzoulis, Lidia Tosi (ELETTRA, Basovizza,
Trieste)
Optical asymmetries have been measured and
analyzed, before and after the magnet realignments.
One way is to compare theoretical to measured orbit
response matrices. Another way is to analyze the
measured response matrix itself, by comparing the
measured effects at identical optical positions. To
evaluate the effects of the sextupoles on the optical
asymmetries, the measurements have been performed
with the sextupoles ON and OFF. The impact of a
partial realignment is also analyzed both by varying the
quadrupole excitations as well as by performing
dispersion and coupling measurements. The results are
presented in this paper.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
19-757 - Lattice for CELLS
Marc Munoz, Dieter Einfeld (CELLS, Bellaterra
(Cerdanyola del Vallès))
The CELLS is an approved project to build a national
synchrotron light source in Spain. The main goals of
the project are to provide a medium energy machine (3
GeV) with low emittance and top up operation, a
circumference of ~280 m and at least 12 straight
sections available for experiments. At present, two
lattices are being considered. The first one is based in
QBA optics and provides and emittance of 5 nm-rad,
using existing technologies. The second one is a TBA
one, with an emittance of 2 nm, where physical
aperture are reduced by at least a factor 2 and gradients in
the bending magnets are up to 10 T/m. We present the
selected lattice, and review the main beam dynamics (energy
acceptance, errors) issues.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
20-786 - Beam Optical Design of a Multi Charge Ion
Recirculator for Charge Breeders
Rainer Cee, Wolfgang Mittig, Antonio Carlos Villari
(GANIL, Caen)
Ions of high charge states as required for both stable and
radioactive beams in order to optimally profit from the
existing accelerating voltage can be produced by means of a
charge breeder. However, the energy increase obtained is
accompanied by an intensity decrease due to the low
efficiency of the charge breeding process. With respect to
the production of radioactive beams an enhancement of the
breeding efficiency would be most desirable to avoid a high
power primary beam as yet inevitable to counteract the loss
in intensity. For this purpose the beam optics of an ion
recirculation capable to separate the desired charge state and
to reinject the remaining charge spectrum has been
designed. The ions extracted from both sides of the charge
breeder are focused by electrostatic quadrupole doublets and
bent by two 180 dipole magnets. After one revolution the
optics realises horizontally a (1:1) and vertically a (1:-1)
point-to-point image independent from the charge state of
the ions. The second order geometric aberrations as well as
most of the chromatic aberrations vanish.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
21-792 - Effect of Measured Multipole Field Errors on
the SNS Accumulator RingBeam Dynamics
Sarah M. Cousineau (ORNL/ASD, Oak Ridge, Tennessee),
Alexei V. Fedotov, Animesh Kumar Jain, Yong Yung Lee,
Deepak Raparia (BNL, Upton, Long Island, New York),
Stuart Henderson, Jeffrey Alan Holmes, Michael Plum
(ORNL/SNS, Oak Ridge, Tennessee)
Field surveys performed on all of the SNS accumulator ring
quadrupole and dipole magnets have resulted in a complete
set of magnet multipole errors. A significant sextupole
component has been observed in one family of quadrupole
magnets. The impact of the measured multipole errors on
the beam dynamics and the tunability of the SNS
accumulator ring is studied using the ORBIT and UAL
particle tracking codes.
Additionally, a quadrupole
placement scheme that minimizes the effect of the sextupole
field error is examined.
SNS is managed by UT-Battelle, LLC, under contract DEAC05-00OR22725 for the U.S. Department of Energy
SNS is a partnership of six national laboratories: Argonne,
Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos
and Oak Ridge
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
22-795 - Beam Dynamics Simulations at the SDALINAC for the Optimal Position of Beam
Energy Monitors
Bastian Steiner, Wolfgang F.O. Müller, Thomas
Weiland (TEMF, Darmstadt), Achim Richter (TU
Darmstadt, Darmstadt)
The S-DALINAC is a 130 MeV superconducting
recirculating electron accelerator serving several
nuclear and radiation physics experiments as well as
driving an infrared free-electron laser. For the
experiments an energy stability of 1E-4 should be
reached. Therefore noninvasive beam position
monitors will be used to measure the beam energy. For
the measurement the different flight time of the
electrons to the ideal particle are compared, that means
in the simulations the longitudinal dispersion of the
beam transport system is used for the energy detection.
The results of the simulations show that it is possible to
detect an energy difference of 1E-4 with this method.
The results are also proven by measurements.
Work supported in part by DFG under contract SFB
634
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
23-810 - COD Measuring And Correction at
SIBERIA-2
Alexandre Valentinov, Iouri Krylov, Yury Yupinov
(RRC Kurchatov Institute, Moscow)
Electron closed orbit distortion (COD) is measured by
24 beam position monitors (BPM) with 10 micron
accuracy at SIBERIA-2 storage ring. A number of
linear mathematical methods for COD correction are
available, such as RMS minimization, MICADO, SVD.
Correction system now allows to achieve rather small
rms values of COD (at azimuths of BPMs) which are
close to 0.2 mm in vertical plane and 0.7 mm in
horizontal one by using 12 correctors in each
transversal direction, though we have less than 4
monitors for one betatron oscillation (working point Qx
= 7.775, Qz = 6.695). In order to get a better COD
control we used gradient correction coils, which are
situated in each quadrupole lens. Change in gradient of
one lens leads to orbit deviation on BPM azimuths if
there is a difference dy between beam position inside
the lens and its magnetic axe. COD measured by BPMs
can be matched with theoretically calculated one using
dy as a parameter. So we can find electron beam
positions in 72 points (number of quadrupoles). This
information can be used for calibration of BPM
positions relative to quadrupoles positions and in
correction schemes. In the report the results of orbit
measurements by both methods are presented with an
indication of the accuracy. The results of COD
corrections at the different energies of Siberia-2 ring
are described.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
24-868 - Transverse Coupling Measurement using SVD
Modes from Beam Histories
Chun-Xi Wang (ANL, Argonne, Illinois), Rama Calaga
(BNL, Upton, Long Island, New York)
In this report we investigate the measurement of local
transverse coupling from turn-by-turn data measured at a
large number of beam position monitors. We focus on a
direct measurement of coupled lattice functions using the
Singular Value Decomposition (SVD) modes and explore
the accuracy of this method. The advantages and
shortcomings of this model-independent method for
coupling measurement will be also discussed.
Work supported by U.S. Department of Energy, Office of
Basic Energy Sciences, under Contract No. W-31-109ENG-38
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
25-869 - Algorithm to Untangle Mixed Modes in Modelindependent Analysis of Rings
Chun-Xi Wang (ANL, Argonne, Illinois)
SVD mode analysis is a basic techinique in ModelIndependent Analysis of beam dynamics. It decomposes the
spatial-temporal variation of a beam centroid into a small set
of orthogonal modes based on statistical analysis. Although
such modes have been proven to be rather informative, each
orthogonal mode may not correspond to an individual
physical source but a mix of several in order to be
orthogonal. Such mixing makes it difficult to quantitatively
understand the SVD modes and thus limits their usefulness.
Here we report a new techinique to untangle the mixed
modes in storage ring analysis based on the fact that most of
the physical modes in a ring have identifiable characteristics
in frequency domain.
Work supported by U.S. Department of Energy, Office of
Basic Energy Sciences, under Contract No. W-31-109ENG-38
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
26-905 - Operational Measurement of Coupling by Skew
Quadrupole Modulation
Yun Luo, Peter Cameron, Al Marusic, Fulvia Caterina Pilat,
Thomas Roser, Dejan Trbojevic (BNL, Upton, Long Island,
New York)
The measurements of betatron coupling via skew
quadrupole modulation is a new diagnostics technique that
has been recently developed and tested at RHIC. By
modulating the current of different skew quadrupole
families with different frequencies and measuring the
resulting eigentunes response with a high resolution phase
lock loop (PLL) system, it is possible to determine the
projections of the residual coupling coefficients. We report
the results of extensive beam studies carried on at RHIC
injection, store energy and on the ramp. The capability of
measuring coupling on the ramp opens the possibility of
continuous coupling corrections during acceleration.
Work performed under the auspices of the US
Department of Energy
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
27-906 - Principle of Skew-quadrupole Modulation
for Transverse Couplingmeasurement
Yun Luo, Thomas Roser, Dejan Trbojevic, Jie Wei
(BNL, Upton, Long Island, New York)
The idea of modulating Skew Qudrupoles to measure
the ring betatron coupling was put forth by T. Roser. In
this paper, analytical solutions for this technique is
given. Simulation are also carried out based on RHIC.
And other relevent issues concerning this technique's
application are also discussed. All of them show this
idea of modulating skew qudrupoles to measure the
betatron coupling are applicable.
Work performed under the auspices of the US
Department of Energy
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
28-921 - Multiple-charge-state Beam Steering in
High-intensity Heavy-ion Linacs
Eliane Schnirman Lessner, Peter Ostroumov
(ANL/Phys, Argonne, Illinois)
An algorithm suitable for correction to steering of
multiple-charge-state beams in heavy-ion linacs
operating at high currents has been developed [*]. It
follows a four-dimensional minimization procedure
that includes coupling of the transverse beam motions.
A major requirement is that it obeys the restricted
lattice design imposed by the acceleration of multiplecharge-state heavy-ion beams [**]. We study the
algorithm efficiency in controlling the beam effective
emittance growth in the presence of random
misalignments of cavities and focusing elements.
Limits on misalignments are determined by quantifying
beam losses and effective steering requirements are
selected by examining several correcting schemes
within the real-state constraints. The algorithm is used
to perform statistically significant simulations to study
beam losses under realistic steering.
Work supported by the U. S. Department of Energy
under contract W-31-109-ENG-38
* E. S. Lessner and P. N. Ostroumov, Proc. Part.
Accel. Conf. (2003)
** P. N. Ostroumov, Phys. Rev. STAB Vol. 5,
0030101 (2002)
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
29-955 - Investigation of Injection through Bending
Magnet Fringe Fields in X-rays Source NESTOR
Andrey Mytsykov, Peter Gladkikh, Alexandr Valerij
Ryezayev, Andrey Yurij Zelinsky (NSC/KIPT, Kharkov)
In paper injection in the X-rays source NESTOR
through fringe fields of a bending magnet is
considered. The simulation of a motion of a beam of
charged particles through 3-d fields of magnetic
devices of the injection channel, which ones is located on a
ring, are performed. The focusing properties of the injection
channel are determined.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
30-959 - The Operation Modes of Kharkov X-ray
Generator based on Compton Scattering NESTOR
Peter Gladkikh, Eugene Victor Bulyak, Ivan Karnaukhov,
Andrey Mytsykov, Alexander Shcherbakov, Andrey Yurij
Zelinsky (NSC/KIPT, Kharkov)
The results of theoretical and numerical considerations of
linear Compton scattering are used to evaluate
characteristics of X-rays produced by collision between a
low emittance electron beam and intensive laser light in an
X-rays generator NESTOR of NSC KIPT. Two main
generation modes have been under consideration at
preliminary NESTOR design. There are the operation mode
for medicine 33.4 keV X-rays production using 43 Mev
electron beam and Nd:YAG laser beam and higher energy
X-rays production mode providing X-rays with energy up to
900 keV with 225 MeV electron beam and Nd:YAG laser
beam. It is supposed to use an optical cavity for laser beam
accumulation of about 2.6 m long and an interaction angle
of about 30 in both operation modes. A few more operation
modes provide possibility to expand operation range of
NESTOR. Using interaction angle 100 and 1500 along with
optical resonator 42 or 21 cm long and the second mode of
laser light it is possible to produce X-rays in energy range
from a few keV till 1.5 MeV. The intensity and spectral
brightness of the X-rays is expected to be ~ 1013 phot/s and
~ 1013 phot/s/mm2/mrad2/0.01%BW respectively.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
31-960 - Lattice of NSC KIPT Compact Intense X-ray
Generator NESTOR
Alexander Shcherbakov, Peter Gladkikh, Ivan Karnaukhov,
Vasilij Markov, Andrey Mytsykov, Vasilij Skirda, Andrey
Yurij Zelinsky (NSC/KIPT, Kharkov)
The new generation of the intense X-rays sources based on
low energy electron storage ring and Compton scattering of
laser beam allows to produce X-rays with intensity up to
1014 phot/s. One of the main traits of a storage ring lattice
for such generator type is using of magnetic elements with
combined focusing functions such as bending magnets with
quadrupole and sextupole field components. In combination
with very low bending radius and dense magnetic elements
setting along ring circumference it leads to increasing of 3D
magnetic field effects on electron beam dynamics and can
decrease generated radiation intensity drastically. For the
reasons of very low electron beam size at the interaction
point and strong focusing in a compact storage ring the
questions of determination of accuracy of bending magnet is
very important too. The paper is devoted to the description
of lattice of NSC KIPT Compact X-ray generator NESTOR.
The results of investigations of the effects of 3D magnetic
field and harmonic compound due to manufacture errors of
bending magnets, bending magnet and lenses edges on
electron beam dynamics are presented.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
32-963 - NESTOR Reference Orbit Correction
Vadim Anatolij Ivashchenko, Peter Gladkikh, Ivan
Karnaukhov, Andrey Mytsykov, Vladimir Trotsenko,
Andrey Yurij Zelinsky (NSC/KIPT, Kharkov)
It is known that intensity of scattered radiation in Xrays generators based on Compton scattering strongly
depends on relative position of electron and laser
beams. For this reason it is very important to have
effective system of reference orbit correction and beam
position control as well along whole ring as at the
interaction point. In the paper the results of design and
development of reference orbit correction system for
compact storage ring NESTOR are presented. The total
reference orbit correction will be carried out in vertical
plane only. Correctors will be disposed on quadrupole
lenses and will be provide reference orbit correction
angle up to 0.10. The local correction at the interaction
point will be provided with four correctors located at
the interaction straight section. In the article results of
calculations, layout of whole system, quadrupole lenses
and pick-up station parameters and schemes are
presented.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
33-999 - Non-destructive Beam Measurements
Mei Bai (BNL, Upton, Long Island, New York)
In high energy accelerators especially storage rings,
non-destructive beam measurements are highly
desirable to minimize the impact on the beam quality.
In principle, the non-destructive tools can be either
passive detectors like Schottky, or active devices which
excite either longitudinal or transverse beam motions
for the corresponding measurements. An example of
such a device is ac dipole, a magnet with oscillating
field, which can be used to achieve large coherent
betatron oscillations. It has been demonstrated in the
Brookhaven AGS that by adiabatically exciting the
beam, the beam emittance growth due to the
filamentation in the phase space can be avoided. This
paper overviews both techniques in general. In
particular, this paper also presents the beam tune
measurement with Schottky detector, phase advance
measurement as well as non-linear resonance
measurements with the ac dipoles in the Brookhaven
RHIC.
This work is performed under the auspices of the US
DOE
Type of presentation requested: This is an Invited
Oral Presentation
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
34-1025 - Efficient Modeling for Beam-beam
Interactions
Michael G. Zeitlin, Antonina N. Fedorova (RAS/IPME, St.
Petersburg)
We consider modeling for strong-strong beam-beam
interactions beyond the standard perturbative methods. In
our approach, based on projection methods and efficient
functional space decomposition in localized bases with
control of convergence for a nonlinear and/or singular
integral operators (Hilbert transform) based models, the full
possible spectrum, partly discovered before (discrete
coherent and possible incoherent oscillations), appears as
the result of the exact multiresolution/multiscale fast
convergent decomposition in the bases of high-localized
nonlinear modes. The constructed solutions represent the
full multiscale spectrum with contributions from all internal
hidden modes from the slow to fast oscillating eigenmodes.
The underlying methods provide some sort of the
algebraical control of the spectrum and the type of
dynamical behaviour.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
35-1087 - Observation of Coupling Resonance in
HIMAC Synchrotron
Tomonori Uesugi, Koji Noda (NIRS, Chiba-shi)
Coupling resonance was observed at operating points near to
Qx-Qy=1. Two-dimensional profile of a beam at its
equilibrium was measured, and it was found that the beam
was inclined in transverse when the operating point is near
to the resonance condition. We will present the detail of the
measurement and the results.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
36-1091 - Combined Beam Dynamics Study of the RFQ
and DTL for PEFP
Ji-ho Jang, Yong-Sub Cho, Hyeok-Jung Kwon (KAERI,
Daejon)
One of the goals of the Proton Engineering Frontier Project
(PEFP) is to get 20 MeV proton beams of 20 mA through a
3 MeV RFQ and a 20 MeV DTL. This work is related to the
combined beam dynamics study of the low energy proton
accelerators in order to test the validity of the connection of
the independently designed structures as well as to study the
MEBT for beam transportation.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
37-1127 - Linear Optics Diagnostics and Vertical
Emittance Optimization at the Pohang Light Source.
Seunghwan Shin, Moohyun Yoon (POSTECH, Pohang,
Kyungbuk), Eun-San Kim (PAL, Pohang)
The vertical emittance increase reduces the brightness of the
machine. The dominant sources of the vertical emittance are
the both of vertical dispersion and x-y orbit coupling in the
ring. A computer code LOCO (Linear Optics from Closed
Orbit) was used to correct the gradient errors of the lattice at
the PLS. (Pohang Light Source) With the corrected
optics and SVD algorithms, Orbit and vertical
dispersion are simultaneously corrected for the vertical
emittance optimization.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
38-1128 - Optimization Studies on BEPCII Future
Pre-injector with Two SHBs
Shilun Pei, Pengda Gu, bo liu, Shu-hong Wang (IHEP
Beijing, Beijing)
The BEPCII future pre-injector consists of a thermionic
gun followed by two subharmonic bunchers (SHB), a
travelling wave prebuncher and a travelling wave
buncher. All components downstream of the gun are
immersed in a solenoid field for transverse focusing.
Beam dynamics simulation and optimization have been
carried out with programs PARMELA and EGUN.
SHBs' bunching voltage and bunching drift distance,
prebuncher and buncher's phase and acceleration
gradient, and solenoid field profile have been studied.
The bunch charge limitation for 10 ps bunch length at
the buncher exit is also investigated.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
39-1159 - Measurement of Linear Lattice Functions
in the ESRF Storage Ring Using Turn-by-turn Data
Yannis Papaphilippou, Laurent Farvacque (ESRF,
Grenoble), Stephanie-Louise Bailey (The College of
William and Mary, Williamsburg)
A model-independent method to measure linear optics
functions has been tested in turn-by-turn data from the
ESRF storage ring. This method does not necessitate
neither the knowledge of the machine's optics model
nor magnetic element manipulation. It uses only the
positions measured in consecutive BPMs of betatron
oscillations issued by small transverse kicks. The phase
advances and tunes necessary to construct the transfer
matrices are issued by refined Fourier analysis. The
method's precision is compared with classical methods
such as response matrix analysis and beam matrix
construction.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
40-1178 - Online Calculation of the Beam
Trajectory in the HERA Interaction Regions
Frank Brinker (DESY, Hamburg)
During the HERA luminosity upgrade the new super
conducting mini beta quadrupoles have been placed
inside the experiments for final focussing and
separation of the lepton and proton beams. The
synchrotron radiation of up to 12 kW produced in these
magnets passes through the detector and is absorbed
behind the experiments. In order to avoid background
events from synchrotron radiation it is a mandatory to
adjust precisely the beam trajectory before and inside
the detector. A procedure has been developed to
calculate the trajectory in the interaction regions. With
a beam-based alignment the offsets of the beam with respect
to the quadrupoles is measured. From this measurement the
offsets of the quadrupoles and of the beam position monitors
are fitted. With the knowledge of these offsets the trajectory
of the beam is calculated with high precision. The display of
the trajectory is online available as an operational tool for
beam steering and background optimization.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
41-1192 - Dispersion Correction in HERA
Joachim Keil, Winfried Decking (DESY, Hamburg)
The electron-proton collider HERA at the DESY laboratory
in Hamburg has been in operation since 1991. After the
luminosity upgrade of HERA in 2001 the control of the
horizontal and vertical dispersion function of the positron
beam became more important than before. Deviations from
the design dispersion in the horizontal plane can change the
emittance of the electron beam significantly thus leading to
a reduction of the luminosity. For optimizing the
polarization of the electron beam the reduction of vertical
orbit and dispersion deviations is important. In this paper the
combined dispersion and orbit correction in HERA is
described and first results are reported.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
42-1195 - Measuring and Adjusting the IP Betafunctions in RHIC.
Walter Wittmer, Frank Zimmermann (CERN, Geneva),
Angelika Drees, Fulvia Caterina Pilat, Johannes Van Zeijts
(BNL, Upton, Long Island, New York)
The beta- functions at the IP can be adjusted without
perturbation of other
optics functions via several
approaches. In this paper we describe a scheme based on a
vector knob, which assigns fixed values to the different
tuning quadrupoles and scales them by a common
multiplier. The values for the knob vector were calculated
for a lattice without any errors using MADX. Previous
studies for the LHC have shown that this approach can meet
the design goals. A specific feature of the RHIC lattice is the
nested power supply system. To cope with the resulting
problems a detailed response matrix analysis has been
carried out and different sets of knobs were calculated and
compared. The knobs are tested at RHIC during the 2004
run
and
preliminary
results
maybe
discussed.
Simultaneously a new approach to measure the beam sizes
of both colliding beams at the IP, based on the tune ability
provided by the knobs, was developed and tested.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
43-1200 - Calculating LHC Tuning Knobs using Various
Methods.
Walter Wittmer, Daniel Schulte (CERN, Geneva)
By measuring and adjusting the beta-functions at the IP the
luminosity is being optimized. In LEP this was done with
the two closest doublet magnets. This approach is not
applicable for the LHC due to the asymmetric lattice and
common beam pipe through the triplet magnets. To control
and change the beta-functions quadrupole groups
situated on both sides further away from the IP have to
be used where the two beams are already separated.
The quadrupoles are excited in specific linear
combinations, forming the so-called tuning knobs for
the IP beta-functions. We compare the performance of
such knobs calculated by different methods: (1)
matching in MAD, (2) inversion of the re-sponse
matrix and singular value decomposition inversion and
conditioning and (3) conditioning the response matrix
by multidimensional minimization using Hessian
method.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
44-1272 - Deflection Element for S-LSR
Masahiro Ikegami, Hicham Fadil, Akira Noda,
Toshiyuki Shirai, Takeshi Takeuchi, Mikio Tanabe
(ICR Kyoto, Kyoto), Hiromu Tongu (ICR/NSRF,
Kyoto), Koji Noda, Hirotsugu Ogawa, Shinji Shibuya
(NIRS, Chiba-shi)
Main lattice of the ion storage and cooler ring, S-LSR
is composed of 6 dipole and 12 quadrupole magnets.
The maximum magnetic field, the radius of curvature
and gap height are 0.95 T, 1050 mm and 70 mm,
respectively. The field measurement of the dipole
magnets has been completed with use of Hall-probe
position controlled by driving mechanism composed of
stepping motors and ball-screws. In order to cancel out
the momentum dispersion, the radial electric field is
superposed with the magnetic field. The radial electric
field is applied by the electrodes installed into the
vacuum vessel set inside the rather limited gap of the
dipole magnet. Good field quality is to be realized
with use of intermediate electrodes. In the present
paper, the results of the magnetic field measurements
are presented together with the design of the
superposed electric field.
Supported financially by Advance Compact
Accelerator Development of
Ministry of Education, Culture, Sports, Science and
Technology
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
45-1315 - Measuring Local Gradient and Skew
Quadrupole Errors in RHIC IRs
Javier Fernando Cardona, Steve Peggs, Fulvia
Caterina Pilat, Vadim Ptitsyn (BNL, Upton, Long
Island, New York)
The measurement of local linear errors at RHIC
interaction regions using an "action and phase" analysis
of difference orbits has already been presented [*].
This paper evaluates the accuracy of this technique
using difference orbits that were taken when known
gradient errors and skew quadrupole errors were
intentionally introduced. It also presents action and
phase analysis of simulated orbits when controlled
errors are intentionally placed in a RHIC simulation
model.
Department of Energy and Colciencias
* J. Cardona, S. Peggs, T. Satogata, F. Pilat and V.
Ptitsyn,"Determination of Linear and Non Linear
Components in RHIC Interaction Regions from difference
Orbit Measurements", EPAC 2002, Paris, 2002, p.311-313.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
46-1351 - LOCO Based Modell Analysis at DELTA
Marc Grewe, Detlev Schirmer, Gerald Schmidt, Klaus Wille
(DELTA, Dortmund)
DELTA is a 1.5 GeV electron storage ring with a complex
but versatile magnet lattice including 3 families of dipoles
and 78 quadrupoles grouped into 25 families. Together with
56 external sextupole yokes, the machine lattice resembles a
rather tight packing. The inherent twofold symmetry breaks
with certain insertion devices turned on. Applying the
LOCO algorithm, the condition number for quadrupole
gradient variation alone typically ranges around 2x10^7 and
above. Previous attempts to match a theoretical model with
experimental data failed to generate a self consistent model.
More elaborate attempts include a careful analysis of
solutions corresponding to small singular values.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
47-1354 - Orbit Stability Issues at the Brazilian
Synchrotron Light Source
Lin Liu, Ruy H.A. Farias, Lucia Cabral Jahnel, Pedro
Tavares (LNLS, Campinas)
In this report we describe orbit stability problems that
appeared in the LNLS electron storage ring after the
installation of a new RF cavity during the last machine
shutdown.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
48-1366 - Design of the Proton Beam Line for the Trade
Experiment
Concetta Ronsivalle, Luigi Picardi (ENEA C.R. Frascati,
Frascati (Roma))
The
TRADE
(Triga
Accelerator
Driven
Experiment)experiment, to be performed in the TRIGA
reactor of the ENEA-Casaccia centre consists in the
coupling of a 140-300 MeV, 0.5 mA proton beam produced
by a cyclotron to a target hosted in the central thimble of the
reactor scrammed to sub-criticality. A 30 m long beamline
has been designed to transfer the beam injecting it from the
top of the pool with special care of having low losses in
TRIGA building where a limited shielding of the line is
possible. A particular attention was paid to reduce the
number and size of elements in the last part of the beamline
that are immersed in the pool's water. The paper presents a
description of the beam line, the design criteria and the
results of beam dynamics calculations.
The work was performed in the frame of an
international working group on the TRADE experiment
including ENEA(Italy), CEA(France),CERN
(Switzerland),ANSALDO(Italy),FZK(Germany),DOE(
USA),CIEMAT(Spain),CNRS(France),JRCITU(EU),PSI(Switzerland),AAA(France),AI
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
49-1368 - Achieving Beam Quality Requirements
for Parity Experiments at Jefferson Lab
Yu-Chiu Chao (Jefferson Lab, Newport News,
Virginia)
Measurement of asymmetry between alternating
opposite electron polarization in electron-nucleon
scattering experiments can answer important questions
about nucleon structures. Such experiments impose
stringent condition on the electron beam quality, and
thus the accelerator used for beam creation and
delivery. Of particular concern to such ?parity?
experiments is the level of correlation between beam
characteristics (orbit, intensity) and electron
polarization that can obscure the real asymmetry. This
can be introduced at the beam forming stage, created
due to scraping, or not damped to desired level due to
defective transport. Suppression of such correlation
thus demands tight control of the beam line from
cathode to target, and requires multi-disciplined
approach with collaboration among nuclear physicists
and accelerator physicists/engineers. The approach
adopted at Jefferson Lab includes reduction of
correlation source, improving low energy beam
handling, and monitoring and correcting global
transport. This paper will discuss methods adopted to
meet the performance criteria imposed by parity
experiments, and ongoing research aimed at going
beyond current performance.
U.S. DOE Contract No DE-AC05-84-ER40150
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
50-1386 - Normal Form Analysis of Linear Beam
Dynamics in a Coupled Storage Ring
Mark Woodley, Tor Raubenheimer (SLAC/NLC, Menlo
Park, California), Andrzej Wolski (LBNL/AFR,
Berkeley, California)
The techniques of normal form analysis, well known in
the literature, can be used to provide a straightforward
characterization of linear betatron dynamics in a
coupled lattice. Here, we consider both the beam
distribution and the betatron oscillations in a storage
ring. We find that the beta functions for uncoupled
motion generalize in a simple way to the coupled case.
Defined in the way that we propose, the beta functions
remain well behaved (positive and finite) under all
circumstances, and have essentially the same physical
significance for the beam size and betatron oscillations
as in the uncoupled case. Application of this analysis to
the online modeling of the PEP-II rings is also
discussed.
Work supported by the U.S. Department of Energy under
contracts DE-AC03-76SF00098 and DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
51-1415 - Simple Analytic Formulae for the Properties of
Nonscaling FFAG Lattices
Shane Rupert Koscielniak (TRIUMF, Vancouver), Michael
Craddock (UBC & TRIUMF, Vancouver, British Columbia)
A hallmark of the "non-scaling" FFAG lattices recently
proposed for neutrino factories and muon colliders is that a
wide range of momentum is compacted into a narrow radial
band; dL/L is of order 10^(-3) for dp/p of order unity. This
property is associated with the use of F0D0 or FDF triplet
lattices in which the F magnet provides a reverse bend. In
this paper simple analytic formulae for key lattice
properties, such as orbit displacement and path length as a
function of momentum, are derived from thin-element
models. These confirm the parabolic dependence of pathlength on momentum observed with standard orbit codes,
reveal the factors which should be adjusted to minimize its
variation, and form a useful starting point for the thickelement design (for which analytic formulae are also
presented). A key result is that optimized doublet, F0D0 and
triplet cells of equal length and phase advance have equal
path-length performance. Finally, in the context of a 10-20
GeV/c muon ring, the thin-element formulae are compared
against lattice optical properties computed for thick-element
systems; the discrepancies are small overall, and most
discernible for the triplet lattices.
TRIUMF receives funding via a contribution agreement
through the National Research Council of Canada
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
52-1420 - Orbit Response Matrix Analysis applied at
PEP-II
Christoph Steier, Andrzej Wolski (LBNL/AFR, Berkeley,
California), Stanley Ecklund, Peter Tenenbaum (SLAC,
Menlo Park, California), Gerald Yocky (SLAC/AD, Menlo
Park, California), James Leslie Turner (SLAC/ARDB,
Menlo Park, California), Tor Raubenheimer (
Beam-based techniques to study lattice properties have
proven to be a very powerful tool to optimize the
performance of storage rings. The analysis of orbit response
matrices has been used very successfully to measure and
correct the gradient and skew gradient distribution in many
accelerators. The first applications were mostly in
synchrotron light sources, but the technique is also used
increasingly at colliders. It allows determination of an
accurately calibrated model of the coupled machine lattice,
which then can be used to calculate the corrections
necessary to improve coupling, dynamic aperture and
ultimately luminosity. At PEP-II, the Matlab version of
LOCO has been used to analyze coupled response matrices
for both the LER and the HER. The large number of
elements in PEP-II and the very complicated interaction
region present unique challenges to the data analysis. The
orbit response matrix analysis will be presented in detail, as
well as results of lattice corrections based on the calibrated
machine model.
This work was supported by the U.S. Department of
Energy, under Contract No. DE-AC03-76SF00098 and
DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
53-1424 - Magnetized Beam Transport in Electron
Coolers with Opposing Solenoid Fields
Jorg Kewisch, Christoph Montag (BNL, Upton, Long
Island, New York)
To improve cooling capability of electron coolers
magnetized beams in strong solenoid fields are used.
Too avoid betatron coupling in the ion coupling
compensation is required. For the RHIC electron cooler
we propose a scheme consisting of two identical
solenoids with opposing fields, connected by a
quadrupole matching section that preserves the electron
beam magnetization. Since the fringe fields of the
individual magnets overlap, the matching section can
not be designed with standard optics codes. We
developed an optimization code based on particle
tracking instead. Input for the program are the
simulated/measured field maps of the magnets. We
demonstrate that the transverse temperature of the
electron beam does not increase.
Work performed under the auspices of the U.S.
Department of Energy
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
54-1453 - Aperture Studies for the AP2 Anti-proton
Line at Fermilab
Ina Reichel (LBNL/CBP, Berkeley, California), Keith
Gollwitzer, Steve Werkema (Fermilab, Batavia,
Illinois), Massimo Placidi, Michael Zisman (LBNL,
Berkeley, California)
The AP2 beamline transports anti-protons from the
production target to the Debuncher ring. In the past the
observed aperture has been smaller than that estimated
from linear, on-energy optics. We have investigated
possible reasons for the aperture limitation and have
identified possible sources, including residual vertical
dispersion from alignment errors and chromatic effects
due to very large chromatic lattice functions. Some
experiments have already been performed to study
these effects. We present results of the experimental
and theoretical studies and possible remedies.
This work was supported by the U.S.Department of
Energy under Contract No. DE-AC03-76SF00098
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
55-1536 - Lattice Design of Large Acceptance
FFAGs for the PRISM Project
Akira Sato (Osaka University, Osaka), Shinji Machida
(KEK, Ibaraki)
In order to realize a super muon beam that combines
high-intensity, low-energy, narrow energy-spread and
high purity, the PRISM project has been proposed. In
this project, a FFAG ring is used as a phase rotator. In
this paper, a method of designing the PRISM-FFAG lattice
will be described. The PRISM-FFAG has to have both of
large transverse acceptance and large momentum acceptance
to achieve high intensity. Furthermore, long straight sections
to install RF cavities are required to obtain a high surviving
ratio of the muon. Therefore, the PRISM-FFAG requires its
magnets to have large aperture and small opening angle. In
such magnets, not only nonlinear effects but also magnetic
fringing field are important to study the beam dynamics of
FFAGs. Although using realistic 3D magnetic field maps
made with programs such as TOSCA is the best solution to
study the FFAG dynamics, it takes long time to make such
field maps. On a design process of the PRISM-FFAG, quasirealistic 3D magnetic field maps, which are calculated
applying spline interpolation to POISSON 2D field, were
used to study the beam dynamics. A program based on
GEANT3.21 was used for particle tracking.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
56-1622 - The Comparison with the Finger Focus and
the Normal Lens by the OPERA-3D
Kazuo Yamamoto, Toshinori Mitsumoto, Masahiro
Okamura (RIKEN, Saitama)
We calculated electric field between drift tubes with fingers
by means of the simulation soft OPERA-3D. There will be
focus field by the fingers like RFQ linac and also have high
acceleration field like DT linac. We compared with the
finger focus and the normal magnetic lens focus and it will
be reported the advantage of the finger focus in some energy
region.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
57-1644 - Synthesis of Beam Lines with Necessary
Properties
Serge Andrianov (St. Petersburg State University, St.
Petersburg)
In this paper an author discusses an approach to the problem
of synthesis of beam lines. Usually this problem can be
overcome by the use of numerical simulation and optimal
control theory methods. But this results in sufficiently great
number of variable parameters and functions. Obviously,
that this degrades quality of modeling procedure. The
suggested approach is demonstrated on a problem of
microprobe design problem. Essence of the problem is that
necessary to design a high precision focusing system which
satisfies the additional conditions. For this purpose we use
an algebraic treatment based on Lie algebraic methods and
computer algebra codes. The used approach allows overlaid
beam properties stultified to enough simple conditions on
control parameters and functions. This allows us to build a
set of desired solutions and show results in the most
favourable form. Moreover, this approach decreases the
number of variable parameters.
Russian Foundation for Basic Research
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices, Correction
Schemes, Transport
58-1742 - Heavy Ion Beam Transport in Plasma
Channels
Stephan Neff, R. Knobloch (TU Darmstadt,
Darmstadt), Christoph Niemann, Dan Penache,
Andreas Tauschwitz (GSI, Darmstadt), Dieter
Hoffmann (GSI, Darmstadt; TU Darmstadt,
Darmstadt), Simon Yu (LBNL, Berkeley, California)
The transport of heavy ion beams in high current
discharge channels is a promising option for the final
beam transport in a heavy ion fusion reactor. The
channel provides space-charge neutralization and an
azimuthal magnetic field of several tesla, thereby
allowing for transporting high current ion beams. The
possibility to heat the hohlraum target with only two
ion beams simplifies the reactor design significantly.
Therefore channel transport is studied as part of the US
fusion reactor study as an alternative to neutralized
ballistic focusing. We have created 1 m long discharge
channels and studied the channel development and
stability. In addition, we have carried out proof-ofprinciple transport experiments using the UNILAC
facility at the Gesellschaft für Schwerionenforschung.
The experiments demonstrate the feasibility of plasma
channel transport. Our transport experiments with low
current beams are supplemented by simulations for
high current beams. These simulations show the
possibility of transporting particle currents of up to 60
kA.
Type of presentation requested: Poster
Classification: [D01] Beam Optics - Lattices,
Correction Schemes, Transport
59-236 - Nonlinear Beam Dynamics Study with
MATLAB
Yuri Lawrent Martirosyan, Michael Ivanyan, Davit
Kalantaryan, Vasili Mkrtich Tsakanov (CANDLE,
Yerevan)
In this paper, we present description of MATLAB
based computer code, which allows tracking of single
particles by numerical integration of Hamilton's
equations. For storage rings the damping time is of the
order of few ms (102 '104 turns) and therefore the
short-term stability time is determinant. For this reason
symplecticity condition of the tracking method for the
electron machines is not as important as in hadron
machines. Applying recently introduced modern tools
for post process analyzing, such as interpolated FFT,
early indicators for long term stability, the
determination of the onset of chaotic behavior using
the maximal Lyapunov exponent, and etc, one can
carry out simulations to evaluate the dynamic aperture,
amplitude dependent tunes, phase space distortions,
nonlinear resonances etc. The proposed code is applied
for beam nonlinear dynamics study in CANDLE
storage ring.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
60-269 - Beam-beam Simulations for the Electron-ion
Collider eRHIC
Christoph Montag (BNL, Upton, Long Island, New York)
The electron-ion collider eRHIC currently under study at
BNL consists of a 10 GeV electron storage ring to be added
to the existing RHIC complex to study collisions of
polarized electrons and relativistic heavy ions or polarized
protons. To achieve high luminosities in the range of several
10^32 cm^-2 sec^-1, beam-beam tuneshift parameters of up
to 0.08 are required for the electron beam. Simulation
studies are performed to study the feasibility of these high
tuneshift parameters. Recent results of these studies are
presented.
Work performed under the auspices of the U.S. Department
of Energy
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
61-275 - A Test Suite of Space-charge Problems for Code
Benchmarking
Andreas Adelmann (PSI, Villigen), Ji Qiang, Robert D Ryne
(LBNL/CBP, Berkeley, California)
A set of problems is presented for benchmarking beam
dynamics codes with space charge. As examples, we show
comparisons using the IMPACT, MaryLie/IMPACT, and
MAD9P codes. The accuracy and convergence of the
solutions as a function of solver algorithms, simulations
parameters such as number of macro particles, grid size, etc.
are studied.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
62-363 - Beam Loss Modeling for the SIS100
Giuliano Franchetti, Ingo Hofmann (GSI, Darmstadt)
In long term storage dynamic aperture is typically regarded
as the quantity which has to be maintained sufficiently large
in order to prevent beam loss. In the SIS100 of the GSI
future project, a beam size occupying a large fraction of the
beam pipe is foreseen. This circumstance requires a careful
description of the lattice magnetic imperfections. The
dynamic aperture is estimated in relation with an
optimization of the SIS100 working point. For a spacecharge-free bunched beam, estimates of beam loss are
computed and compared with dynamic aperture. The impact
of space charge will be discussed, and preliminary results on
its effect on dynamic aperture and beam loss are presented.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
63-429 - Towards DAFNE Nonlinear Model
Mikhail Zobov, David Alesini, Maria Biagini, Caterina
Biscari, Alessandro Drago, Susanna Guiducci, Catia
Milardi, Miro Preger, Pantaleo Raimondi, Cristina
Vaccarezza (INFN/LNF, Frascati (Roma)), Evgeny
Levichev, Pavel Piminov (BINP, Novosibirsk)
Intensive numerical and experimental study of the beam
nonlinear dynamics is continuously pursued in order to
provide a reliable description of the DAFNE rings nonlinear
elements. Localized orbit bumps, beam decoherence and
chromaticity measurements have been performed and
compared to the predictions of the model. The
effectiveness of the second order chromaticity
correction by means of octupoles has been checked by
measuring the tune shift dependence on the RF
frequency. Numerical simulations based on the updated
model have been used for the dynamic aperture
optimization.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
64-431 - Beam Loading in the RF Deflector of the
CTF3 Delay Loop
David Alesini, Fabio Marcellini (INFN/LNF, Frascati
(Roma))
In this paper we describe the impact of the beam
loading in the RF deflectors on the transverse beam
dynamics of the CTF3 Delay Loop. The general
expression for the single passage wake field is
obtained. A dedicated tracking code has been written to
study the multi-bunch multi-turn effects on the
transverse beam dynamics. A complete analysis for
different machine parameters and injection errors is
presented and discussed. The numerical simulations
show that the beam emittance growth due to the wake
field in the RF deflectors is small.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
65-471 - Beam-Beam Effects Measured Using Gated
Monitors at KEKB
Takao Ieiri, Yoshihiro Funakoshi, Takashi Kawamoto,
Mika Masuzawa, Masafumi Tawada, Makoto
Tobiyama, Su Su Win (KEK, Ibaraki)
KEKB is a multi-bunch, high-current, electron/positron
collider for B meson physics. The two beams collide at
one interaction point (IP) with a finite horizontal
crossing angle and with a bunch-space of 6 to 8 ns. The
luminosity of KEKB is the best in the world. The
collision is performed by carefully adjusting a
horizontal orbit bump of the electron beam at IP, which
results in a horizontal offset to obtain the best
luminosity. In order to investigate the asymmetric
beam-beam effects, beam parameters of collision and
non-collision bunches were compared using beam
monitors capable of selecting a specific bunch in a
bunch train. The beam-beam kick and the beam-beam
tune-shift were obtained by the gated beam-position
monitor and by the gated tune monitor. It was found
that the horizontal offset was negligibly small in the
case of a wide bunch-space of 48 ns. This result
suggests that the horizontal offset is related to wake
fields including electron-cloud effects.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
66-476 - Numerical Studies of the Impact of the
Separation Dipoles and Insertion Quadrupoles Field
Quality on the Dynamic Aperture of the CERN LHC
Massimo Giovannozzi, Oliver Sim Bruning, Stephane David
Fartoukh, Thys Risselada, Frank Schmidt (CERN, Geneva)
A wide range of magnets, both warm and superconducting,
will be used in the LHC. In addition to main dipoles,
quadrupoles are used to focus the beam in regular arcs.
Special dipoles separate or merge the two beams in insertion
regions. A few very strong superconducting quadrupoles
squeeze the beam to achieve the required luminosity, while
warm quadrupoles are used in the collimation insertions. At
injection the main dipoles largely dominate beam dynamics,
but contributions from smaller classes of magnets should not
be neglected. Peculiar optical configurations may
dramatically enhance beam dynamics effects of few
magnetic elements. This paper will focus on the effect of
insertion quadrupoles, e.g. wide-aperture, and warm
quadrupoles, as well as separation dipoles presenting on the
dynamic aperture of the LHC machine.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
67-480 - Advances on Measurements on Multi-turn
Extraction Based on Trapping in Stable Islands at
CERN Proton Synchrotron
Massimo Giovannozzi, Roberto Cappi, Michel Martini,
Elias Metral, Akira Sakumi, Rende Richard Steerenberg
(CERN, Geneva), Anke-Susanne Müller (FZK-ISSANKA, Karlsruhe)
Recently a novel approach to perform multi-turn extraction
was proposed based on beam splitting in the transverse
phase space by means of trapping inside stable islands.
During the year 2002 run, preliminary measurements at the
CERN Proton Synchrotron with a low-intensity, singlebunch, proton beam, confirmed the possibility of generating
various beamlets starting from a single Gaussian beam. The
experimental campaign continued also in the year 2003 run
to assess a number of key issues, such as feasibility of
trapping with high-intensity beam, capture efficiency, and
multi-turn extraction proper. The experimental results are
presented and discussed in detail in this paper.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
68-483 - Nonlinear Dynamics Studies at the CERN
Proton Synchrotron: Precise Measurements of Islands
Parameters for the Novel Multi-turn Extraction
Massimo Giovannozzi, Paolo Scaramuzzi (CERN, Geneva)
Recently, a novel approach to perform multi-turn extraction
from a circular accelerator was proposed. It is based on
adiabatic capture of particles into islands of transverse phase
space generated by nonlinear resonances. Sextupole and
octupole magnets are used to generate these islands, while
an appropriate slow variation of the linear tune allows
particles to be trapped inside the islands. Intense
experimental efforts showed that the approach is indeed
performing rather well. However, good knowledge of the
islands properties is a key ingredient for the success of this
extraction type. In this paper, a series of measurements are
presented dealing with the study of islands' parameters for
the fourth-order resonance, such as detuning with
amplitude, fixed points' position, betatron frequency, as
well as detuning with amplitude inside the islands.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
Work supported by CNPq, Brazil
* R. Pakter and F. B. Rizzato, Phys. Rev. Lett., 87, 044801
(2001)
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
69-531 - Betatron Resonance Studies at the CERN
PS Booster by Harmonic Analysis of Turn-by-turn
Data
Peter Urschütz, Michael Benedikt, Christian
Carli, Michel Chanel, Frank Schmidt (CERN, Geneva)
High brightness and high intensity beams are required
from the PS Booster for LHC, CNGS and ISOLDE
operation. The large space charge tune spreads
associated with these beams, especially at injection,
require an optimized resonance compensation scheme
to avoid beam blow-up and subsequent beam losses.
For this a detailed knowledge on strength and phase of
resonance driving terms is needed. A new
measurement system has been installed to determine
resonance driving terms from turn-by-turn bpm data
using fast Fourier transform. The multi-turn acquisition
system as well as the specific measurement conditions
at the PS Booster are discussed. As an example, the
measurement and compensation of the linear coupling
resonance driving term is presented. Excellent
agreement between measurement and simulation for
resonance phase and strength was found.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
71-538 - Measurement and Compensation of Second and
Third Order Resonances at the CERN PS Booster
Peter Urschütz (CERN, Geneva)
Space charge effects at injection are the most limiting factor
for the production of high brightness beams in the CERN PS
Booster. The beams for LHC, CNGS and ISOLDE feature
incoherent tune spreads exceeding 0.5 at injection energy
and thus cover a large area in the tune diagram.
Consequently these beams experience the effects of
transverse betatron resonances and efficient compensation is
required. Several measurements have been performed at the
PS Booster in 2003, aiming at a detailed analysis of all
relevant second and third order resonances and an
optimisation of the compensation scheme. Special attention
was paid to the systematic 3Qy=16 resonance. To avoid this
particularly dangerous resonance an alternative working
point was tested. A comparison of resonance driving terms
and compensation settings for both working points was
made and important differences in the strengths of the
resonances were found. The peculiarities when measuring
third order coupling resonance driving terms are also
mentioned.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
70-534 - Parameter Depedence of the New Regions
of Stability for Periodically Focused Particle Beams
Renato Pakter, Jorge da Silva Moraes, Felipe Rizzato
(IF-UFRGS, Porto Alegre), Chiping Chen (MIT/PSFC,
Cambridge, Massachusetts)
The understanding of the physics of intense beams in
periodically focusing systems is crucial for the
development of several advanced particle accelerator
applications, as well as applications in basic science. In
this paper we perform a comprehensive analysis of the
transport of periodically focused particle beams within
the new regions of stability recently found [*] for
focusing fields strengths corresponding to vacuum
phase advances well above the 90 degrees threshold.
We investigate the stability as a function of the relevant
parameters of the system, namely, the beam intensity
and the focusing field profile. An analytic model is
developed to show the existence of gap bifurcations in
the system, which may leave the beam envelope phasespace absent of closed orbits. Stability of the beam
transport against both axisymmetric and non
axisymmetric perturbations is considered. Selfconsistent numerical simulations are used to verify the
findings.
72-562 - Nonolinear Evolution of the Beam in Phase
Space at Elettra
Simone Di Mitri, Lidia Tosi (ELETTRA, Basovizza, Trieste)
Phase space in the Elettra storage ring has been investigated.
The beam is kicked and the coordinates of the bunch
centroid are acquired for at least 1000 turns. A Hilbert
transform has been used to deduce the evolution of beam
phase space from position coordinates. Several nonlinear
effects have been detected, such as the amplitude
dependence of the betatron tune, the presence of high order
and coupling resonances. Fixed points have been evidenced
as well as the behaviour of the beam in their neighbourhood.
Scans in lifetime versus tune confirm the limiting effect of
the observed resonances on the region of regular motion.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
73-592 - Measurement of Multipole Strengths from
RHIC BPM Data
Rogelio Tomas, Mei Bai, Wolfram Fischer (BNL, Upton,
Long Island, New York), Andrea Franchi, Giovanni Rumolo
(GSI, Darmstadt)
Recently resonance driving terms were successfully
measured in the CERN SPS and the BNL RHIC from the
Fourier spectrum of BPM data. Based on these
measurements a new analysis has been derived to extract
multipole strengths.In this paper we present experimental
measurements of sextupolar and skew quadrupolar strengths
carried out at RHIC. Also discussed is the possibility of
a non-destructive measurement using an AC dipole.
Work performed under the auspices of the US
Department of Energy
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
74-599 - Separatrix Formalism for Superconducting Linear Accelerators
Yurij Senichev, Alexander Bogdanov, Rudolf Maier
(FZJ/IKP, Jülich)
Super-conducting cavities provide high accelerating
gradient in linear accelerators. However, it is desirable
to have a constant geometry of the accelerating cells in
order to simplify manufacturing. Such geometry leads
to a non-synchronism. A separatrix formalism has been
developed for a super-conducting linear accelerator
based on a model of stationary separatrixes
overlapping, and an effective separatrix, moving
together with a quasi-synchronous particle. This
formalism is applied to two cases: either the phase
velocity changes from cavity to cavity, or the phase
velocity is constant for cavities, belonging to one
family. Solving Hamiltonian equations, it is shown
qualitatively and quantitatively, how the quasisynchronous phase velocity has to be adjusted either by
a stepped phase velocity, or by a stepped RF phasing in
order to minimize the effect of non-synchronism in the
first or the second case.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
75-618 - Experiments on LHC Long-range Beambeam Compensation in the CERN SPS
Frank Zimmermann, Jean-Pierre Koutchouk, Jorg
Wenninger (CERN, Geneva)
Long-range beam-beam collisions may limit the
dynamic aperture and the beam lifetime in storage-ring
colliders. Their effect can be compensated by a currentcarrying wire mounted parallel to the beam. A
compensation scheme based on this principle has been
proposed for the Large Hadron Collider (LHC). To
demonstrate its viability, a prototype wire was installed
at the CERN SPS in 2002. First successful machine
experiments explored the dependence of beam loss,
beam size, and beam lifetime on the beam-wire
distance and on the wire excitation. They appear to
confirm the predicted effect of the long-range
collisions on the beam dynamics. In 2004, two further
wires will become available, by which we can
explicitly demonstrate the compensation, study
pertinent tolerances, and also compare the respective
merits of different beam-beam crossing schemes for
several interaction points.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
76-650 - Frequency Map Measurements at BESSY
Peter Kuske, Olaf Dressler (BESSY GmbH, Berlin)
With two dedicated diagnostic kicker magnets and a turnby-turn, bunch-by-bunch beam position monitor frequency
maps were measured under various operating conditions of
the BESSY storage ring. Depending on the number and type
of insertion devices in operation additional resonances show
up. Details of the experimental setup as well as the data
analysis are presented. The results will be compared with
theoretical calculations which are based on the linear model
of the storage ring lattice extracted from measured response
matrices. Non-linear elements are added to the model in
order to describe the effect of the strong sextupole magnets,
the horizontal corrector magnets installed in these magnets,
and of some of the insertion devices.
Work funded by the BMBF and the Land Berlin
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
77-671 - Non-linear RF Bucket of NewSUBARU due to
the Higher order Momentum Compaction Factor
Yoshihiko Shoji (JASRI/SPring-8, Hyogo)
Linear and higher order terms of the momentum compaction
factor of NewSUBARU were estimated from the
measurements. The linear term was estimated from the shift
of horizontal COD to the RF frequency. Higher order terms
were estimated from the shift of synchrotron oscillation
frequency to the RF frequency. The RF bucket in the user
operation, calculated from these data, was not symmetric for
dE/E>0 and dE/E<0 because of the higher order momentum
compaction factor. It disabled the use of full physical
acceptance of the ring. We will report an improvement of
Touschek beam lifetime by reducing the higher order
momentum compaction factor.
Hyogo prefecture
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
78-674 - Nonlinear field Effects in the JPARC Main Ring
Alexander Yu. Molodojentsev, Shinji Machida, Yoshiharu
Mori (KEK, Ibaraki)
Main Ring (MR) of the Japanese Particle Accelerator
Research Complex (JPARC) should provide acceleration of
the high-intensity proton beam from the energy of 3GeV to
50 GeV. The expected beam intensity is 3.3e14 ppp and the
repetition rate is about 0.3 Hz. The imaginary transition
lattice of the ring was adopted, which has the natural linear
chromaticity about (-30) for both transverse phase planes.
The expected momentum spread of the captured particles
before the acceleration is less than 0.007. Two independent
families of the chromatic sextupole magnets are use to
eliminate the linear chromatic tune shift. This chromatic
sextupole field nonlinearity will excite the normal 'octupole'
resonances and will lead to the amplitude dependent tune
shifts in both transverse phase planes. Additional sextupole
magnets are planed to excite the third-order horizontal
resonance, which will be used for the slow extraction.
Incoherent tune shift of the low-energy proton beam is about
(-0.16) so that some particles could cross nearest low-order
resonances. Optimization of the 'bare' working point of MR
at the injection energy has been performed to minimize the
influence of the linear coupling and high-order
coupling resonances. Excitation of the linear coupling
resonance has been introduced by the realistic
misalignment errors adopted for MR. The 'bare'
working point during the slow extraction has been
analyzed. The influence of the normal sextupole
resonances on the large amplitude particle behavior at
the scraper location has been studied including random
sextupole field component of the MR bending magnets.
Realistic distortion of the ideal ring super-periodicity
by the injection kicker magnets has been included in
the tracking procedure for the on- and off-momentum
particles. Finally, correction schemes have been
considered for most dangerous resonances around the
optimized 'bare' working point. The space-charge
effects of the proton beam have not been included in
this study.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
79-691 - Computer Simulation of Equilibrium
Electron Beam Distribution in the Proximity of 4th
Order Single Nonlinear Resonance
Tzong-Shyan Ueng, Chin-Cheng Kuo (NSRRC,
Hsinchu), Alex Chao (SLAC, Menlo Park, California)
The beam distribution of particles in an electron
storage ring is distorted in the presence of nonlinear
resonances. A computer simulation is used to study the
equilibrium distribution of an electron beam in the
presence of 4th order single nonlinear resonance. The
results are compared with that obtained using an
analytical approach by solving the Fokker-Planck
equation to first order in the resonance strength. The
effect of resonance on the quantum lifetime of electron
beam is also compared and investigated.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
80-706 - Beam Dynamics Study for PETRA III
Including Damping Wigglers
Winfried Decking, Yongjun Li (DESY, Hamburg)
Damping wigglers will be installed in the storage ring
PETRA III to control the beam emittance to 1 nmrad.
These wigglers will produce linear and nonlinear
perturbations on beam dynamics. A new expanded
transport matrix method is developed to solve linear
dynamics, and used to match linear lattice functions.
The symplectic method is adopted to track particle
through the whole ring including the damping
wigglers. Halbach?s formulae are used to describe the
wiggler field. The main parameters of the wigglers are
derived from field calculations. In order to avoid
dangerous resonances, tune scanning is implemented to
find suitable working points. According to presently
known field quality, the nonlinear effects of damping
wigglers will not degrade the performance of PETRA
III and the dynamic aperture is still larger than the
physical aperture.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
81-732 - Dynamic Aperture Reduction from the
Dodecapole Component in the LHC Main Quadrupoles
and its Mechanism.
Alessandra Maria Lombardi, Oliver Sim Bruning, Stephane
David Fartoukh, Thys Risselada, Frank Schmidt, Andre
Verdier (CERN, Geneva)
The systematic dodecapole component in the Main
Quadrupoles of the LHC lattice has a strong influence on
the machine dynamic aperture at injection. In this paper we
quantify this effect with the help of tracking studies, explain
the mechanism for the loss in dynamic aperture and look
into potential correction schemes. Finally, we provide an
estimate for the maximum allowed systematic dodecapole
component in the MQ
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
82-737 - Measurement of Skew Quadrupole Strengths
from BPM Data at GSI SIS-18
Andrea Franchi, Markus Kirk, Peter Moritz, Giovanni
Rumolo (GSI, Darmstadt), Rogelio Tomas (BNL, Upton,
Long Island, New York)
In the SIS-18 of GSI a new set of skew quadrupoles has
been installed to improve the multi-turn-injection. A new
method based on the measurement of the resonance driving
terms has been proposed to cross-check the nominal values
and polarities of their gradients. Once a beam is transversely
kicked, it experiences oscillations whose spectrum contains
both the betatron tune line and secondary lines. The
amplitude of each line is proportional to the strength of the
multipoles, such as skew quadrupoles and sextupoles,
present in the lattice. In this paper a recursive algorithm to
derive the magnet strength from the spectral lines and the
application of this method to the eight skew quadrupoles in
the SIS-18 are presented.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
83-747 - Optimization of Beam Dynamics in Discrete
Systems
Elena Dmitrievna Kotina (St. Petersburg State University,
St. Petersburg)
In this paper new approach to optimization of beam
dynamics in discrete systems is considered. Dynamics of
synchronous particle and dynamics of ensembles of charged
particles are optimized simultaneously. We consider this
problem as the non-standart problem of the theory of
optimal control in discrete systems. This problem of control
of particular trajectory and ensembles of trajectories (beams
of trajectories)had been investigated under various criteria
of quality. The method of solving of this problem is
proposed. This method is applied to optimization of the
motion of charged particles in the drift-tube linear
accelerator.
This work was supported by the Russian Fund of
Fundamental Research, project 03-01-00726
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
84-753 - Longitudinal Resonances and Emittance
Growth Using QWR/HWR Cavities in a Linac
Patrick Bertrand (GANIL, Caen)
In the frame of the SPIRAL II project at GANIL, we
present an analytical approach allowing us to
understand in a simple way the longitudinal behaviour
of a beam , transmitted in bunching mode or
accelerated in a Linac designed with QWR or HWR
cavities. In particular, we make appear the strong
relationship with the Henon map properties.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
85-764 - Influence of Beam Tube Obstacles on the
Emittance of the PITZ Photoinjector
Stefan Setzer, Wolfgang Ackermann, Thomas Weiland
(TEMF, Darmstadt)
For detailed analysis of space charge dominated beams
inside an RF Photoinjector PIC-Codes like MAFIA
TS2/3 can be used. While the interaction of particles
with the sourrounding geometries are taken into
account, the applicability of such codes is restricted
due to simulation time and memory consumption as
well as by numercial noise. Therefore only smaller
sections of the whole injector can be calculated. On the
other hand codes like ASTRA can be used to simulate
the whole injector but no interaction between bunch
and geometry is included. To make use of the
individual advantages of each code discribed above an
interface for bidirectional bunch exchange between the
two programs has been implemented. This approach
allows for applying the right simulation method
depending on the physical effects under investigation.
To demonstrate the importance of such an approach the
results of detailed numerical studies of the impact of
beam tube obstacles like the laser mirror on the
achievable emittance of the PITZ RF Photoinjector
further downstream will be presented.
S.Setzer: Work supported by DFG under contract GRK
410/3
W. Ackermann: Work supported by DESY Hamburg
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
86-767 - On Beam Dynamics Optimization
Dimitri Ovsyannikov (St. Petersburg State University,
St. Petersburg)
Mathematical optimization methods are widely used in
designing and construction of charged particle
accelerators. In this paper new approach to beam
dynamics optimization is considered. Suggested
approach to the problem is based on the analytical
representation for variation of examined functionals via
solutions of special partial differentional equations.
The problem of optimization is considered as a
problem of mutual optimization chosen synchronous particle
motion and charged particles beam at whole. This approach
was applied to the beam dynamics optimization for RFQ
structures.
This work was supported by the Russian Foundation for
Fundamental Researhes, project 03-01-00726
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
87-787 - Performance of the TU/e 2.6 Cell Rf-photogun
in the 'Pancake' Regime
Bas van der Geer, Jom Luiten (TUE, Eindhoven), Marieke
de Loos (PP, Soest), Gisela P&#246;plau (Rostock
University, Rostock)
The 2.6 cell rf-photogun currently in operation at Eindhoven
University of Technology has been designed as a booster for
a 2 MeV semi-DC accelerator with a field of 1 GV/m. In
this paper we present GPT simulation results of the TU/e
gun, operated without its pre-accelerator, in the low-charge
short-pulse regime. The main part of the paper describes
detailed calculations of bunch lengthening due to pathlength differences and space-charge effects, making use of
high-precision field-maps and the newly developed 3D
mesh-based space-charge model of GPT. It is shown that
with the present set-up bunches can be produced that are
well suited for injection into a planned experiment for
controlled acceleration in a plasma-wakefield accelerator.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
88-797 - New Vortices in Axisymmetric Beams in
Nonuniform Magnetic Field
Yurii Golub (MRTI RAS, Moscow)
We analyzed localized vortices in non-neutral
inhomogeneous by density and velocity electron beams
propagating in vacuum along the nonuniform external
magnetic field. These vortices distinguish from vortices,
which investigated in [*,**], because of nonuniform
external magnetic field. Also new types of vortex are
obtained by new solution method of nonlinear equations*.
The new method is development of a method described in
[**]. That method distinguish from standard LarichevReznik or Reznik method, which used in [*]. It has been
found new expression for electric field potential of vortex in
a wave frame. The expression is axisymmetric in a wave
frame. New vortices are new solitons in the nonuniform
external magnetic field.
* Golub Yu.Ya., Nikulin M.G., Rozanov N.E. In: Nonlinear
world: IV Intern. Workshop on Nonlin. and Turbul. Proc.
in Phys., (ed. by V.G. Bar'yakhtar et all) World Scientific
Publishing Co. Pte. Ltd., Singapore, 1990, vol. 2, p.857
** Golub Yu.Ya., Proc
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
89-821 - Symplectic Renormalization Group
Reduction of Maps
Stephan Ivanov Tzenov (Universita' degli Studi di
Salerno, Baronissi)
Based on the Renormalization Group (RG) method, a
reduction procedure preserving the symplecticity of
originally symplectic maps is proposed. It utilizes the
method of canonical transformations applied to discrete
dynamical systems, which automatically assures the
symplecticity of the reduced RG map. A few important
examples such as the Henon map and polynomial maps
of higher order are worked out in detail.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
90-852 - Stochastic Behaviour of Nonlinear Maps
Stephan Ivanov Tzenov (Universita' degli Studi di
Salerno, Baronissi)
The Frobenius-Perron operator is used to study the
evolution of the density distribution for nonlinear
symplectic maps. An evolution operator map is derived
in explicit form, which is further applied to calculate
the diffusion coefficient for a general nonlinear twodimensional map. As an example a few important cases
are analyzed in detail.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
91-865 - Beam Loss Studies in High-intensity
Heavy-ion Linacs
Peter Ostroumov, Vladislav Aseev, Eliane Schnirman
Lessner, Brahim Mustapha (ANL/Phys, Argonne,
Illinois)
A low beam-loss budget is an essential requirement for
high-intensity machines and represents one of their
major design challenges. In a high-intensity heavy-ion
machine, losses are required to be below 1 W/m for
hands-on-maintenance. The driver linac of the Rare
Isotope Accelerator (RIA) is designed to accelerate
beams of any ion to energies from 400 MeV per
nucleon for uranium up to 950 MeV for protons with a
beam power of up to 400 kW. The high intensity of the
heaviest ions is achieved by acceleration of multiplecharge-state beams, which requires a careful beam
dynamics optimization to minimize effective emittance
growth and beam halo formation. For beam loss
simulation purposes, large number of particles must be
tracked through the linac. Therefore the computer code
TRACK [P.N. Ostroumov and K.W. Shepard, PRST
AB 11, 030101 (2001)] has been parallelized and
calculations is being performed on the JAZZ cluster [*]
recently inaugurated at ANL. This paper discusses how
this powerful tool is being used for simulations for the
RIA project to help decide on the high-performance
and cost-effective design of the driver linac.
Work supported by the U. S. Department of Energy under
contract
W-31-109-ENG-38
* The Jazz Cluster, http://www.lcrc.anl.gov/jazz
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
92-889 - Higher Order Hard Edge End Field Effects
J. Scott Berg (BNL, Upton, Long Island, New York)
In most cases, nonlinearities from magnets must be properly
included in tracking and analysis to properly compute
quantities of interest, in particular chromatic properties and
dynamic aperture. One source of nonlinearities in magnets
that is often important and cannot be avoided is the
nonlinearity arising at the end of a magnet due to the
longitudinal variation of the field at the end of the magnet.
Part of this effect is independent of the shape of the end. It
is lowest order in the body field of the magnet, and is the
result of taking a limit as the length over which the field at
the end varies approaches zero. This is referred to as a hard
edge" end field. This effect has been computed previously
to lowest order in the transverse variables. This paper
describes a method to compute this effect to arbitrary order
in the transverse variables, under certain constraints. The
results of using this hard edge model are compared with
performing the computation with finite-length end fields, as
well as to the lowest-order hard-edge end field model.
This research has been supported by the U.S. Department of
Energy under contract no. DE-AC02-98CH10886
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
93-891 - Magnetic Field Expansions
J. Scott Berg (BNL, Upton, Long Island, New York)
In many simulation and analysis applications, it is necessary
to have magnetic fields which satisfy Maxwell's equations
over some finite volume. This is achieved by specifying
some subset of the field information, and using Maxwell's
equations to find an expression for the fields everywhere in
some volume. Two possible expansions are known as a
midplane expansion and a multipole expansion. This paper
specifies these expansions precisely and demonstrates the
differences between them. In particular, a precise definition
of a multipole expansion in a curvilinear coordinate system
is given.
This research has been supported by the U.S. Department of
Energy under contract no. DE-AC02-98CH10886
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
94-892 - Momentum Compaction Factor and Nonlinear
Dispersion at the ANKA Storage Ring
Anke-Susanne M&#252;ller, Asem BenKalefa, Ingrid Birkel,
Erhard Huttel, Francisco Perez, Montserrat Pont (FZK-ISSANKA, Karlsruhe)
The ANKA electron storage ring operates in the energy
range from 0.5 to 2.5 GeV. In order to improve machine
performance a precise modelling of linear and nonlinear
optics is mandatory. Apart from higher order chromaticity
also momentum compaction factor and dispersion have
to be controlled. In this framework, the higher order
momentum compaction factor has been determined
exploiting the extraordinary precision of the resonant
spin depolarisation method. Furthermore the nonlinear
horizontal dispersion was measured as a function of the
momentum deviation for different chromaticities. This
paper discusses the experimental results and compares
the findings to different simulations.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
95-954 - Specific Beam Dynamics in Super-bunch
Acceleration
Yoshito Shimosaki, Yoshio Arakida, Eiji Nakamura,
Ken Takayama, Masayoshi Wake (KEK, Ibaraki),
Kunio Koseki (GUAS/AS, Ibaraki), Kota Torikai
(Kyushu University, Fukuoka), Masao Watanabe
(RIKEN, Saitama), Kazuhiko Horioka, Mitsuo
Nakajima (TIT, Yokohama)
Proof-of-principle experiments on the induction
synchrotron concept using the KEK 12-GeV PS makes
progress, in which RF bunches and a super-bunch will
be accelerated with a long step voltage generated in the
induction accelerating gaps. In order to give a guide
for super-bunch acceleration, the beam stabilities
against a droop and a fluctuation of the accelerating
voltage have been examined by using a simulation.
The droop voltage gives an additional focusing or
defocusing force in the longitudinal direction, which
leads the mismatching beyond the transition energy.
Furthermore, the extremely slow fluctuation of the
accelerating voltage causes a lowest-order resonance
near the transition. These induce a serious emittance
blow-up in the longitudinal, so that the compensating
manners will be presented. Moreover, the other issues
such as head-tail instability and intra beam scattering
will be discussed.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
96-983 - Performance of the Non-linear Interaction
Region Correction in RHIC
Fulvia Caterina Pilat, Severino Binello, Peter
Cameron, Wolfram Fischer, Yun Luo, Vadim Ptitsyn,
Rogelio Tomas (BNL, Upton, Long Island, New York)
The non-linear corrector layers in the triplets next to
the high luminosity interaction points in RHIC have
been used in RHIC operations. Local sextupoles and
octupoles were set by minimizing the tune shifts versus
IR bump amplitude, using a dedicated control room
application, which includes order-by-order fitting and
plotting. The operational corrections are compared to
dead-reckoned predictions derived from measured field
harmonics in the IR triplets. The RHIC offline model
has been used to evaluate the effect of operational and
dead-reckoned corrections, and to compare beam
quantities to experimental observations. Measurable
quantities that we used to assess the non-linear
performance of the machine are tune shifts versus IR
bump amplitude, beam lifetime, dynamic aperture, and tune
spread.
Work supported by U.S. DOE under contract No DE-AC0298CH10886
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
97-984 - Dynamic Aperture Predictions and
Measurements in RHIC
Fulvia Caterina Pilat, Nikolay Malitsky, Vadim Ptitsyn,
Steven Tepikian (BNL, Upton, Long Island, New York)
With RHIC achieving now operational maturity, more
attention has been devoted in 2004 to beam experiments
characterizing the machine non-linear behavior. A method
of measuring dynamic aperture by increasing the transverse
emittance with continuous tune meter kicks has been
developed and tested. The ionization profile monitor (IPM)
capability of bunch-by-bunch measurement allows us to
effectively use different bunches for measurements in
different machine configurations. We present dynamic
aperture measurements for the blue and yellow rings at store
energy and for the high luminosity optics (b*=1m) and
compare results at different working points, momentum
deviation, and interaction region corrector configurations.
The 2004 b*=1m data are compared to dynamic aperture
results from 2003 with b*=2m. The experimental results are
also compared with recent dynamic aperture prediction for
the 2004 optics configuration from the RHIC offline model
to assess our present understanding of the machine model
itself.
Work supported by U.S. DOE under contract No DE-AC0298CH10886
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
98-993 - Lattice Studies for CIRCE (Coherent InfraRed
CEnter) at the ALS
Hiroshi Nishimura, David Robin, Fernando Sannibale,
Weishi Wan (LBNL, Berkeley, California)
CIRCE (Coherent InfraRed Center) at the Advanced Light
Source is a proposal for a new electron storage ring
optimized for the generation of coherent synchrotron
radiation (CSR) in the terahertz frequency range. One of the
main requirement for this special mode of operation is the
capability of the ring of operating at very small momentum
compaction values. In this regime, the longitudinal
dynamics becomes strongly nonlinear and an accurate
control of the higher order energy dependent terms of the
momentum compaction is necessary. The lattice for CIRCE
allows controlling these terms up to the third order. The
paper describes the lattice and presents the calculated
performances in terms of momentum acceptance, dynamic
aperture, lifetime and momentum compaction tune
capabilities.
Work supported by the U.S. Department of Energy under
Contract No. DE-AC03-76SF00098
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
99-1041 - Fast Methods for Vlasov-Poisson
Dynamics
Michael G. Zeitlin, Antonina N. Fedorova (RAS/IPME,
St. Petersburg)
A fast and efficient numerical-analytical approach is
proposed for modeling the complex nonlinear
collective behaviour in the various forms of the
generalized Vlasov-Poisson systems. We compare our
approach with previous ones, e.g. nonlinear delta F
simulation and PIC modeling and demonstrate its
advantages. As the particular limiting cases of our
construction we have standard KV and Klimontovich
distributions. The solutions are represented via the
multiscale decomposition in nonlinear high-localized
eigenmodes (generalized Gluckstern modes), which
corresponds to the full multiresolution expansion in all
underlying hidden phase space scales. In contrast with
different approaches we do not use perturbation
technique
or
linearization
procedures.
Fast
scalar/parallel modeling demonstrates the appearance
of the high-localized (asymptotically stable) coherent
structures/patterns (waveletons) in these spatiallyextended stochastic systems with complex collective
behaviour.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
100-1045 - Zoo of Patterns in Complex VlasovMaxwell Dynamics
Michael G. Zeitlin, Antonina N. Fedorova (RAS/IPME,
St. Petersburg)
An exact variational/projection approach is proposed
for modeling the complex collective behaviour and the
propagation of the intense charged particle beams
described by different forms of Vlasov-Maxwell
equations. We give representations for distribution
functions and fields via the multiscale/multiresolution
decomposition corresponding to exact expansions into
the slow and fast nonlinear high-localized eigenmodes
providing the full information about stochastic
dynamical process. Numerical modeling shows the
creation of different internal structures from localized
modes, which are related to stable/unstable type of
behaviour and the corresponding patterns (waveletons)
formation. Reduced algebraical structure provides the
pure algebraical control of stability/unstability
scenario. Various types of patterns (chaotic and
localized) are controlled in space of parameters.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
101-1098 - Field Measurements in the AGS Warm
Snake
Junpei Takano, Toshiyuki Hattori, Masahiro Okamura
(RIKEN, Saitama), Rodulfo Alforque, Richard Belkin,
George Ganetis, Animesh Kumar Jain, Waldo MacKay,
Thomas Roser, Richard Thomas, Joseph Tuozzolo
(BNL, Upton, Long Island, New York)
A new warm snake has been produced for avoiding the
transverse coupling resonance in the Alternating
Gradient Synchrotron (AGS) at Brookhaven National
Laboratory (BNL). The warm snake is the world?s first
normal conducting helical dipole partial snake which has a
double pitch structure to allow spin rotation with no net
beam offset or deflection with a single magnet. The warm
snake is 2.6m long, and has a field of 1.5 Tesla for a 9
degrees spin rotation. The pitches, current density, and
shims were optimized by using OPERA_3D / TOSCA. The
magnetic field harmonics have been measured using a
system of 51 mm long, 34 mm radius tangential coils. The
axial variation of the dipole field angle agrees very well
with the calculations, indicating no significant construction
errors. However, the measured transfer function shows a
discrepancy of 4% which may be caused by BH-curve
differences, deformation of the iron and packing factor of
the laminations. To correct the beam trajectory the operating
current was adjusted and shims were installed on the end
plates. These optimization studies, and comparison with
measurements, will be shown.
RIKEN
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
102-1104 - Frequency Map Analysis with the Insertion
Devices at ELETTRA
Lidia Tosi, Simone Di Mitri (Sincrotrone Trieste S.C.p.A.,
Basovizza, Trieste), Guimin Liu (SSRF, Shanghai)
Frequency map analysis is a very efficient technique for the
understanding of the resonances which may affect the
stability of the electrons. Measurements correlated to
simulations can provide a method to improve beam lifetime
and injection efficiency that is particulary important in the
case of top up operation. In this paper, the results of
frequency map measurements and simulations for the
ELETTRA storage ring are presented both for the bare
lattice as well as for the case in which insertion devices are
operational.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
103-1154 - Experimental Frequency Maps for the ESRF
Storage Ring
Yannis Papaphilippou, Laurent Farvacque, Eric Plouviez
(ESRF, Grenoble), Charalampos Skokos (Academy of
Athens, Athens), Jacques Laskar (IMCCE, Paris)
Experimental frequency maps have already revealed many
unknown characteristics of the ESRF storage ring non-linear
dynamics. In the past year, several efforts were undertaken
in order to establish this technique as an operational on-line
tool. The acquisition time was significantly reduced by
collecting data from a dedicated fast BPM system. The
problem of beam decoherence was limited by establishing a
method for accurate tune determination in a small number of
turns, using the information from all the BPMs around the
ring. The possibility to explore the off-momentum dynamics
by exciting the beam, with synchronous transverse and
longitudinal kicks was also investigated. Finally,
measurements of resonance driving term amplitudes and
phase advances were used to identify the efficiency of
resonance corrections.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
104-1157 - A Study of Transverse Resonance
Crossing in FFAG
Masamitsu Aiba (University of Tokyo, Tokyo), Shinji
Machida, Yoshiharu Mori (KEK, Ibaraki)
A study of "resonance crossing" in FFAG accelerator is
described in this paper. A deviation of FFAG guiding
field in actual magnet breaks zero chromaticity
condition, and tunes cross resonance while
acceleration. In order to avoid a critical beam loss or
emittance growth, nominal tune should be chosen so as
not to cross low-order resonances. However, crossing
higher order resonance can be critical and that depends
on the parameters such as crossing speed, excitation
magnitude and initial beam emittance. We will present
analytical model and simulation study in various
parameter space.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
105-1168 - Status Report on the Beam Dynamics
Developments for the SPIRAL 2 Project
Romuald Duperrier, Didier Uriot
(CEA/DSM/DAPNIA, Gif-sur-Yvette), Nicolas Pichoff
(CEA/DAM, Bruyères-le-Châtel), Patrick Bertrand,
Franck Varenne (GANIL, Caen), Jean-Luc Biarrotte
(IPN, Orsay), Jean-Marie De Conto (ISN, Grenoble),
Emmanuel Froidefond (LPS
The driver for the SPIRAL 2 project aims to accelerate
a 5 mA D+ beam up to 20 A.MeV and a 1 mA beam
for Q/A=1/3 up to 14.5 A.MeV. It operates in a
continuous wave regime (cw), is designed for a
maximum efficiency in the transmission of intense
beams. Recent studies have led to change the reference
design. The current design consists in an injector (ECR
sources + LEBTs with the possibility to inject from
several sources + a Radio Frequency Quadrupole)
followed by a superconducting section based on an
array of independently phased cavities where the
transverse focalisation is performed by warm
quadrupoles. This paper presents the beam dynamics
studies associated to these new choices, the HEBT
design and the fast chopping in the MEBT.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
106-1170 - The IFMIF High Energy Beam
Transport Line
Didier Uriot, Romuald Duperrier
(CEA/DSM/DAPNIA, Gif-sur-Yvette), Jacques Payet
(CEA/CEN, Gif-sur-Yvette)
The IFMIF project (International Fusion Materials
Irradiation Facility) requests two linacs designed to
accelerate 125 mA deuteron beams up to 40 MeV. The
linac has to work in CW mode and uses one RFQ and
10 DTL tanks. After extraction and transport, the
deuteron beams with strong internal space charge
forces have to be bunched, accelerated and transported
to target for the production of high neutron flux. This paper
presents the high energy beam transport line which provides
a flat rectangular beam profile on the liquid lithium target.
Transverse uniformisation is obtained by using non-linear
mutipole lenses (octupoles and duodecapoles). Beam
dynamics with and without errors has been study.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
107-1179 - 2-nd Order Sextupole Effects on the Dynamic
Aperture in HERA-e
Mathias Vogt (DESY, Hamburg)
During the first year after the luminosity upgrade HERA-e
was operated in a mode for which the accessible area in
transverse tune space was determined by resonances driven
by sextupoles in 2-nd order. It turned out that with typical
total incoherent beam beam tune shifts (.05,.08) for 2 IPs
this space was too small for stable operation. We have used
2-nd order canonical perturbation theory to analyze the
impact of the increased sextupole strengths in the upgraded
lattice on the relevant resonance strengths and the detuning.
Moreover, we have studied whether it is possible to
compensate the resonances with localized octupole schemes
(6 or 9 independent magnets) to 1-st and 2-nd order,
computed the resulting detuning and compared the results
with 6D tracking.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
108-1185 - Lattice Studies For The MAX-IV Storage
Rings
Hamed Tarawneh, Mikael Eriksson, Lars-Johan Lindgren,
Sverker Werin (MAX-lab, Lund), Bengt Anderberg
(AMACC, Uppsala), Erik Jan Wall&#233;n (ESRF,
Grenoble; MAX-lab, Lund)
The lattice for the future MAX-IV storage rings at MAXLab has been studied, The MAX IV facility consists of two
similar rings operated at 1.5 GeV and 3 GeV electron
energies, The ring consists of 12 supercells each built up by
5 unit cells and matching sections. The high periodicity of
the lattice combined with the high gradients in the small gap
dipole magnets yield a small emittance of 1 nm.rad, good
dynamic aperture and momentum acceptance. In the
matching section, a soft end dipole magnet is introduced to
reduce the synchrotron radiation power hitting the upstream
straight section.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
109-1204 - Non Linear Beam Dynamics and Lifetime on
the SOLEIL Storage Ring
Pascale Brunelle, Alexandre Loulergue, Amor Nadji,
Laurent Stanislas Nadolski (SOLEIL, Gif-sur-Yvette)
The incidence of several non-linear effects on the energy
acceptance and beam lifetime has been investigated, using
the BETA and TRACY II tracking codes. The effect of all
magnets multipolar components has been checked on the
working point (18.20; 10.30), especially the decapolar
component induced by the H-corrector. The dipolar field,
which is created by additional coils in the sextupoles,
generates a significant decapolar component which,
associated to the distributed dispersion, can reduce
significantly the dynamic acceptance at large energy
deviations. This effect depends on the natural closed
orbit to be corrected: corrector strengths and cross talk
between the different decapolar components.
Moreover, the sensitivity to the number of correctors,
used for correction, has been evaluated. The effect of
insertions devices has also been studied, integrating
field maps generated by the RADIA code into the
tracking codes. With undulators, such as an in-vacuum
U20 and an Apple II type HU80 (with different
polarization modes), it was shown that the transverse
field in-homogeneity and the focusing effects
generating beta-beat can affect severely the energy
acceptance and the beam lifetime because of resonance
excitation.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
110-1207 - General Performances of the Injection
Scheme into the SOLEIL Storage Ring
Marie-Agn&#232;s Tordeux (SOLEIL, Gif-sur-Yvette)
The injection scheme of the electron beam into the
Storage Ring of the SOLEIL synchrotron is presented.
It corresponds to the new SOLEIL optics : 12 meter
long straight section, 2.75 GeV energy, with in addition
the requirement for top-up injection mode. Pulsed
magnets are described, and in particular the passive
septum magnet, the transverse position of which can be
adjusted so as to optimise the Touschek beam Lifetime.
Tracking of particles has been performed over a large
number of turns, taking into account the magnet errors,
the high chromaticities and the physical apertures all
along the machine (limited vertical apertures due to
low gap undulators). Statistical efficiency of the
injection has been deduced. Specific requirements for
top-up injection have been examined, such as the
closure of the injection bump, the residual vertical field
and the leakage fields from septa.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
111-1263 - Optimal Control Theory for Solving the
Vlasov-Maxwell Equations
Vladimir Fotievich Zadorozhny (NASU/IOC, Kiev)
A new approach to a nonlinear bunched beam
dynamics based on the Vlasov-Maxwell equations and
optimal control systems. First of all, it?s necessary to
point out the fundamental property of Maxwell
equation which is essential for us. It?s establish that
there exist electric and magnetic fields which can
realized any motion beam is given beforehand. Thus
we resolved the problem of the self-focused and
acceleration particle beam as some mathematical aspect
of optimal control theory with given criterion. This
approach can be regards as a development of the
known algorithm of R. Davidson. This reasoning
yields the following main steps: 1.We have Vlasov
distribution function so that the conditions for the
given transport are satisfies. The one may be the
acceleration, density of current, value of focus, so on. 2. The
idea is to look at as the optimal control problem here we
find distribution function and dispersion waves. Now we
can construct a beam density and current density thus there
exist such fields E and H which provide of a beam according
the low of a fixed motion.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
112-1311 - Building Truncated Taylor Maps with
Mathematica with Applications to FFAG
Dobrin Kaltchev (TRIUMF, Vancouver)
Lie algebra tools coded directly in Mathematica have been
used to compute the off-momentum closed orbit and
momentum compaction of Fixed Field Alternating Gradient
(FFAG) lattices proposed for muon acceleration. The
sample FFAG cell considered consists of quadrupoles and
alternating gradient magnets. A high order Taylor map is
needed, valid over a wide momentum range. This paper
emphasizes on the Mathematica operators needed to create
and concatenate individual element maps (presented as Lie
exponential operators). The speed achieved is inferior to the
differential algebra method (COSY). One benefit is that
Mathematica allows all results to be tested by direct
numerical integration of the equations of motion.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
113-1323 - Non-linear Modeling of the RHIC Interaction
Regions
Rogelio Tomas, Wolfram Fischer, Animesh Kumar Jain, Yun
Luo, Fulvia Caterina Pilat (BNL, Upton, Long Island, New
York)
For RHIC's collision lattices the dominant sources of
transverse non-linearities are located in the interaction
regions. The field quality is available for most of the
magnets in the interaction regions from the magnetic
measurements, or from extrapolations of these
measurements. We discuss the implementation of these
measurements on the MADX models of the Blue and the
Yellow rings and their impact on beam stability.
Work performed under the auspices of the US
Department of Energy
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
114-1358 - Non Linear Error Analysis from Orbit
Measurements in SPS and RHIC
Javier Fernando Cardona, Rogelio Tomas (BNL, Upton,
Long Island, New York)
Recently, an "action and phase" analysis of SPS orbits
measurements proved to be sensitive to sextupole
components intentionally activated at specific locations in
the ring. In this paper we attempt to determine the strenght
of such sextupoles from the measured orbits and compare
them with the set values. Action and phase analysis of orbit
trayectories generated by RHIC models with non linearities
will also be presented and compare with RHIC experiments.
Department of Energy and Colciencias
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
115-1450 - Dynamical Maps for Combined Solenoid,
Dipole and Quadrupole Fields
Andrzej Wolski (LBNL/AFR, Berkeley, California),
Marco Venturini (LBNL, Berkeley, California)
The interaction regions of colliders invariably include
strong solenoid fields. Where quadrupoles and dipoles
are embedded in the solenoid, the beam dynamics in
the combined fields can be complicated to model using
the traditional approach of interleaving slices of
different fields. The complexity increases if the design
trajectory is offset from the magnetic axis; this is the
case, for example, in PEP-II. In this paper, we present
maps for combined solenoid, dipole and quadrupole
fields that provide a much simpler alternative to the
traditional approach, and show that the deviation of the
design trajectory from the magnetic axis can be
handled in a straightforward manner. We illustrate the
techniques presented by reference to the PEP-II
interaction region.
DOE contract no. DE-AC03-76SF00098
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
116-1473 - Single Particle Linear and Non-linear
Dynamics
Yunhai Cai (SLAC, Menlo Park, California)
I will give a comprehensive review of existing particle
tracking tools to assess long-term particle stability for
small and large accelerators in the presence of realistic
magnetic imperfections and machine misalignments.
The emphasis will be given to the tracking and analysis
tools based upon the differential algebra, Lie operator,
and "polymorphism". Using these tools, a uniform
linear and non-linear analysis will be outlined as an
application to the normal form. Finally I will compare
simulation results with observations in existing circular
accelerators. "Model independent analysis" will be
treated as an example for measuring machine optics.
This work was supported by the Department of Energy
under Contract No. DE-AC03-76SF00515
Type of presentation requested: This is an Invited
Oral Presentation
Classification: [D02] Non-linear Dynamics Resonances, Tracking, Higher Order
117-1522 - Installation Strategy for the LHC Main
Dipoles
Stephane David Fartoukh (CERN, Geneva)
All positions in the LHC machine are not equivalent in
terms of beam requirements on the geometry and the
field quality of the main dipoles. In the presence of
slightly or strongly out-of tolerance magnets, a welldefined installation strategy will therefore contribute to
preserve or even optimize the performance of the
machine. In view of present state of the production, we
have anticipated a list of potential issues (geometry,
transfer function, field direction and random b3) which,
combined by order of priority, have been taken into account
to define a robust installation algorithm for the LHC main
dipoles. Among the different possible strategies, the
proposed one has been optimised in terms of simplicity and
flexibility in order not to slow down and complicate the
installation process. Its output is a prescription for installing
the available dipoles in sequence while reducing to an
absolute minimum the number of holes required by
geometry or field quality issues.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
118-1643 - Problems of Conservative Integration in
Beam Physics
Serge Andrianov (St. Petersburg State University, St.
Petersburg)
In this paper some approaches to conservative integration
methods development are discussed. This problem is very
important for beam physics: from beam line synthesis up to
long time evolution simulation. This approach is based on
consistent usage of invariants and symmetries information.
For this purpose on the first level we find or apply
dynamical invariants and symmetries, which should
guarantee the necessary properties. A researcher receives as
a result some set of special conditions for system parameters
(including in symbolic forms). Then these conditions are
included to integration scheme. This procedure looks like to
symplectification procedure for numerical schemes (e.g. the
well known Runge-Kutta
scheme). In this way an
investigator uses the so called kinematic invariants and
symmetries ideology. In our case one obtain a possibility
taking into account the dynamical properties which inhere
(or should inhere) to the system under study. The suggested
approach is demonstrated on some practical problems of
beam physics.
Type of presentation requested: Poster
Classification: [D02] Non-linear Dynamics - Resonances,
Tracking, Higher Order
119-125 - Experimental Results of the Small Isochronous
Ring
Jose Alberto Rodriguez, Felix Marti, Richard York (NSCL,
East Lansing, Michigan), Eduard Pozdeyev (Jefferson Lab,
Newport News, Virginia)
The Small Isochronous Ring (SIR) has been in operation
since December 2003. The main purpose of this ring,
developed and built at the National Superconducting
Cyclotron Laboratory (NSCL) at Michigan State University
(MSU), is to simulate the dynamics of intense beams in
large accelerators. To observe the same effects, the beam
power needed in SIR is orders of magnitude lower and the
time scale is much longer than in the full scale machines.
These differences simplify the design and operation of the
accelerator. The ring measurements can be used to validate
the results of space charge codes. After a variable number of
turns, the injected hydrogen bunch (with energies up to 30
keV) is extracted and its longitudinal profile is measured
using a fast Faraday cup. We present a summary of the
design, the results of the first six months of operation and
the comparison with selected space charge codes.
Work supported by NSF Grant # PHY-0110253
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
120-149 - Clearing of Electron Cloud in SNS with
Solenoid and Electrode
Lanfa Wang, Deepak Raparia, Jie Wei, S.Y. Zhang
(BNL, Upton, Long Island, New York)
In this paper we describe a mechanism using the
clearing electrodes to remove the electron cloud in the
Spallation Neutron Source (SNS) accumulator ring,
where strong multipacting could happen at median
clearing fields. A similar phenomenon was reported in
an experimental study at Los Alamos laboratory's
Proton Synchrotron Ring (PSR). We also investigated
the effectiveness of the solenoid's clearing mechanism
in the SNS, which differs from the short bunch case,
such as in B-factories.
work performed under the auspices of the U.S
Deparment Energy
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
121-151 - Nonlinear Density Waves and Density
Condensates in Space-Charge Dominated Beams
Stephan Ivanov Tzenov, Salvatore De Martino,
Mariarosaria Falanga (Universita' degli Studi di
Salerno, Baronissi)
Based on the Vlasov-Maxwell equations describing the
self-consistent nonlinear beam dynamics and collective
processes, the evolution of an intense sheet beam
propagating through a periodic focusing field has been
studied. In a previous paper, it has been shown that in
the case of a beam with uniform phase space density
the Vlasov-Maxwell equations can be replaced exactly
by the hydrodynamic equations with a triple adiabatic
pressure law coupled to the Maxwell equations. We
further demonstrate that starting from the system of
hydrodynamic and Maxwell equations a set of coupled
nonlinear Schrodinger equations for the slowly varying
amplitudes of density waves can be derived. In the case
where a parametric resonance between a certain mode
of density waves and the external focusing occurs, the
slow evolution of the resonant amplitudes in the coldbeam limit is shown to be governed by a system of
coupled Gross-Pitaevskii equations. Properties of the
nonlinear Schrodinger equation as well as properties of
the Gross-Pitaevskii equation are discussed, together
with soliton and condensate formation in intense
particle beams.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
122-240 - Non Gaussien Transverse Distributions in
a Stochastic Model for Beam Halos
Nicola Cufaro Petroni (INFN-Bari, Bari), Salvatore
De Martino, Silvio De Siena, Fabrizio Illuminati
(Universita' degli Studi di Salerno, Baronissi)
The formation of the beam halo in charged particle
accelerators is studied in a dynamical stochastic model
for the collective motion of the particle beam. The density
and the phase of the charged beam obey a set of coupled
nonlinear hydrodynamic equations with time-reversal
invariance. The linearized theory for this collective
dynamics is given in terms of a classical Schroedinger
equation. Self-consistent solutions with space-charge effects
lead to quasi-stationary beam configurations with enhanced
transverse dispersion and transverse emittance growth. In
the limit of a frozen space-charge core it is possible to
determine and study the properties of stationary, stable coreplus-halo beam distributions. We explore the effect of nonGaussian transverse distributions. In this case the underling
stochastic process is allowed to jump, and the transverse
distribution tails are heavier than in the Gaussian case giving
rise to a halo effect. The stationary transverse distribution
plays the role of an attractor for every other distribution, and
we give an estimation of the time needed by a non
stationary, halo-free distribution to relax toward the
stationary distribution with a halo.
Financial support: INFN (Istituto Nazionale di Fisica
Nucleare) exp. HALODYST
INFM (Istituto Nazionale per la Fisica della Materia)
MIUR (Ministero dell'Istruzione, dell'Universita' e della
Ricerca)
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
123-248 - Optical Stochastic Cooling for RHIC
Vitaly Yakimenko, Ilan Ben-Zvi (BNL, Upton, Long Island,
New York), Alexander Zholents (LBNL/AFR, Berkeley,
California)
We propose the use of an optical parametric amplifier, with
a ~12-micron wavelength for optical-stochastic cooling of
gold ions in the Relativistic Heavy Ion Collider (RHIC).
While this amplifier has a bandwidth comparable to a
Ti:Sapphire laser, it has a higher average output power. Its
12- micron wavelength is longer than that of the laser
amplifiers previously considered for such an application.
The longer wavelength permits a longer undulator period
and higher magnetic field, thereby providing a larger signal
from the pick-up undulator and ensuring a higher efficiency
interaction in the kicker undulator, both essential elements
in cooling moderately relativistic ions. The transition to
longer wavelength also relaxes the requirements for stability
of the path length during ion-beam transport between pickup undulator and kicker undulator. Experimental results of
the optical amplifier test will be discussed.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
124-273 - Collective Effects and Instabilities in Space
Charge Dominated Beams
Jeffrey Alan Holmes (ORNL/SNS, Oak Ridge, Tennessee)
Significant progress in the detailed computational study of
collective beam dynamics is being driven by the spectacular
increase in computer power. To take advantage of this,
sophisticated physics models are being applied to ever more
realistic and detailed situations, so that it is no longer
necessary to restrict computer studies to highly idealized
depictions of beam dynamics questions. This presentation
will illustrate the application of a number of collective beam
dynamics models to a range of accelerator physics
problems in high intensity proton rings. In particular,
we will consider the effects of space charge, transverse
and longitudinal impedances, and electron cloud
formation on beam parameters, stability, halo
formation, collimation and losses, and possible
equilibrium configurations. Examples will be taken
from PSR, the CERN PS Ring, and SNS.
SNS is managed by UT-Battelle, LLC, under contract
DE-AC05-00OR22725 for the U.S. Department of
Energy. SNS is a partnership of six national
laboratories: Argonne, Brookhaven, Jefferson,
Lawrence Berkeley, Los Alamos, and Oak Ridge
Type of presentation requested: This is an Invited
Oral Presentation
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
127-362 - Fast Space Charge Algorithm for an
Ellipsoidal Bunch with Arbitrary Beam Sizes and
Particle Distribution
Giuliano Franchetti, Anna Orzhekovska (GSI, Darmstadt)
For the GSI future project beam loss control of a high
intensity bunched beam stored in SIS100 for 10^6 turns is
an important issue. In a recent study (G. Franchetti et al.,
Phys. Rev. ST Accel. Beams 6, 124201 (2003)) an analytical
space charge algorithm was proposed, which allowed noisefree calculations over a large number of turns. Here we
present a generalization of this algorithm to arbitrary 3D
dimensions and arbitrary distributions observing ellipsoidal
symmetry. Applications to long-term tracking with space
charge are presented
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
125-283 - Beam Dynamics Simulation in High
Energy Electron Cooler
Andrey Ivanov, Vitalij Panasyuk, Vasily Parkhomchuk,
Vladimir Borisovich Reva (BINP, Novosibirsk)
The article deals with electron beam dynamics in
projected high energy electron cooler. Classical
electrostatic scheme with several MeV electron energy
is considered. The increase of transversal energy of
electrons in an accelerating section, in bends and at the
matching point of magnetic fields is calculated. In
order to calculate beam behavior in bends with
electrostatic compensation of centripetal drift new
ELEC3D electro- and magnitostatic 3D code is
developed. BEAM code is used for simulation of
dynamics in an accelerating section. The methods of
keeping low transversal energy are estimated.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
128-364 - Linear Coupling Theory of High Intensity
Beams Applied to the SIS18
Giuliano Franchetti, Morteza Aslaninejad, Ingo Hofmann
(GSI, Darmstadt), Alexander Bolshakov, Pavel Zenkevich
(ITEP, Moscow)
It is planned to use linear coupling in the SIS18 in order to
fully or partially equilibrate the transverse emittances before
transfer to the projected SIS100 synchrotron. In this paper
we show that space charge significantly modifies the
coupling mechanism. In particular the width of the stopband is dominated by the space charge tune shift for weak
skew strength. The conditions are discussed, under which
slow crossing of the coupling resonance leads to the desired
goal of equalizing emittances while maintaining a sufficient
matching of the beam to the ring and extraction optics.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
126-288 - Beam Dynamic Studies of the 72 MeV
Beamline with a 'Super Buncher'
Andreas Adelmann, Stefan Adam, Marco Pedrozzi,
Jean-Yves Raguin, Pierre A Schmelzbach (PSI,
Villigen)
A significant increase of the beam intensity increase of
the PSI 590 MeV proton accelerator facility above 2
mA requires a higher accelerating voltage in the main
RF cavities. A corresponding increase of the voltage in
the flattop cavity would result in a complete rebuild of
this device. As an alternative, a scheme with a strong
buncher in the 72 MeV beam transfer line is being
studied. The goal is to restore the narrow phase width
(~ 2 deg/RF at 50 MHz) of the beam bunches observed
at extraction from Injector 2 at injection into the Ring
Cyclotron. If we can find and inject a stable particle
distribution, as done in the Injector 2, the flat-top
cavity might eventually be decommissioned. First
results of multi particle tracking in full 6 dimensional
phase space with space charge are presented.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
129-403 - Beam Optic Transformation in a High Current
Electron Cooling System
Marina Dolinska, Nataliya Doroshko, Vladislav
Olkchovskiy, Alexander Valkov (NASU/INR, Kiev), Alexei
Dolinskii (GSI, Darmstadt; NASU/INR, Kiev)
A ion beam optic transformation in a high energy electron
cooling system with high electron current density
is
considered. An electron cooling section in a ring is treated
as an additional focusing element deforming the beam optic
functions due to space charge forces The transfer matrix,
which can be implemented in different codes (such as MAD,
MIRKO, SixTrack et al.) for precise calculation of the beam
optic and dynamic aperture in storage rings, is derived. As
an example, an optic of the High Energy Storage Ring
(HESR) calculated by MAD code with derived matrix is
given. The HESR is part of the GSI future project and
planned for internal experiments with antiprotons at a
maximum kinetic energy of 14.5 GeV. In this ring a high
energy electron cooling system will be used to reach the
high luminosity and energy resolutions. Knowing the
focusing properties of the electron cooling section one can
properly match the ring optic function with a cooling section
keeping the stable beam properties in a ring.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
130-405 - UAL Implementation of a String-based
Space Charge Formulation
Richard Michael Talman (LEPP, Ithaca, New York),
Nikolay Malitsky (BNL, Upton, Long Island, New York)
By reformulating the force between point charges as
the force on a point charge due to a co-moving line
charge (or "string",) space charge calculations can be
reformulated as intrabeam scattering, with no
intermediate, particle-in-cell step required.[*] This
approach is expected to be especially useful for
calculating emittance dilution of ultrashort bunches in
magnetic fields, where coherent radiative effects are
important. This paper describes the partial
implementation of this approach within UAL (Unified
Accelerator Libraries.) The interparticle force is
calculated and applied to the dynamics of a bunch
represented by just two superparticles in an idealized
lattice, with emphasis on the head-tail effect. Gridding
of the interparticle force, as needed for realistic
multiparticle simulation, is also described.
U.S. National Science Foundation and U.S.
Department of Energy
* R. Talman, "String Formulation of Space Charge
Forces in a Deflected Bunch". Submitted to PRSTAB,
January, 2004
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
131-425 - Laser Cooling of Electron Bunches in
Compton Storage Rings
Eugene Victor Bulyak (NSC/KIPT, Kharkov)
Self-consistent dynamics of a bunch circulating in the
Compton storage ring has been studied analytically.
Disturbances from both the synchrotron and Compton
radiations were taken into account. The emittances in
laser-dominated rings (where the synchrotron energy
losses are much smaller then the Compton ones) were
evaluated. The resultant emittances (synchrotrons plus
Comptons) were compared with the synchrotrons. As
were shown, the longitudinal degree of freedom is
heated up due to Compton scattering. Almost the same
conclusion is valid for the vertical uncoupled betatron
emittance. Since it is impossible in principle to get zero
dispersion in the banding magnets, the radial emittance
almost always cooling down by laser. Therefore in
practical cases of coupled transverse oscillations with
the horizontal emittance determining the vertical one,
the laser will cool down the transverse degrees of
freedom.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
132-438 - Dynamical Effects of the Montague Resonance
Ingo Hofmann, Giuliano Franchetti (GSI, Darmstadt), Ji
Qiang, Robert D Ryne (LBNL/CBP, Berkeley, California)
In high-intensity accelerators emittance coupling, known as
Montague resonance, may be an issue if the tune split is
small. For static tunes within the stop-band of this fourth
order space charge driven coupling the final emittances may
become equal (equipartition). Using 2D computer
simulation we show, however, that slow crossing of the
resonance leads to merely an exchange of emittances. In 3D
this is similar, if the crossing occurs over a time-scale
shorter or comparable with a synchrotron period. For much
slower crossing we find, instead, that the exchange may be
suppressed by synchrotron motion. We explain this effect in
terms of the mixing caused by the synchrotron motion.
GSI Darmstadt
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
133-442 - Planar Electron Sources and the Electron Trap
ELTRAP
Marco Cavenago (INFN/LNL, Legnaro, Padova), Giovanni
Bettega, Francesco Cavaliere, A. Illiberi, Roberto Pozzoli,
Massimiliano Rome, Luca Serafini (INFN-Milano, Milano)
Filamentation and other space charge effects (both
transverse and longitudinal) of intense electron beams,
found for example in rf photoinjectors (beam energy 1 MeV,
current 100 A), are easily studied in small voltage traps and
drift channels (0.01-10 kV), keeping the same perveance
order. A suitable Malmberg-Penning trap, named ELTRAP,
installed and operated at the University of Milan, is briefly
described; trap length ranges from 10 cm to 1 m; an uniform
magnetic field confines electron radially.
Several
experimental regimes were investigated with the internal
CW planar electron source: plasma, beam-plasma, beam,
depending on the injection/extraction method chosen.
Evolution of electron vortices and virtual cathode formation
is documented; analogy with meteorologic and
astrophysical plasma is discussed. Upgrading with an
external laser pulsed electron source is in course. Larger
planar sources are also under construction. (Main
classification 4: Beam Dynamics and Electro-magnetic
Fields; D03 High Intensity, Incoherent Instabilities, Space
Charge, Halos, Cooling; Other classification 8: Low and
Intermediate Energy Accelerators and Sources; T12 Beam
Injection/Extraction and Transport; T02 Lepton sources)
INFM, MURST, Univ. Milano, INFN
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
134-482 - Space Charge Problem in Low Energy Superconducting Accelerator
Nikita Vasyukhin, Yurij Senichev (FZJ/IKP, Jülich)
At present the super-conducting option of linear accelerators
is considered for low energy, and new type of RF cavities is
considered for this purpose. However, together with
electrodynamics problems we should solve the transverse
stability problem, since in structures with external focusing
elements the focusing period is longer, and in higher
accelerating field the defocusing factor increases as well. In
this paper we consider the transverse stability problem,
taking into account the non-linear space charge
problem. The fundamental mechanism of hallo creation
in super-conducting linear accelerators is investigated
to minimize the particle losses. The theoretical results
are supported by numerical simulation.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
135-528 - High-intensity and High-density Chargeexchange Injection Studies into the CERN PS
Booster at Intermediate Energies
Michel Martini (CERN, Geneva), Christopher Prior
(CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon)
For the high brilliance LHC ultimate beam and the high
intensity CNGS beam, single batch injections into the
CERN Proton Synchrotron (PS) will be used to
increase the overall machine intensity compared with
the present double batch injections. Charge-exchange
injection into the PS Booster with a new linac at
intermediate energies is thus examined. A key
parameter to consider is the energy dependence of
beam incoherent tune shifts at injection. Increasing the
linac energy from the present 50 MeV to 160 MeV
should yield a safer tune shift. For each PS Booster
ring, a charge-exchange injection scheme is envisaged
inside a proper straight section, redesigned with new
bends to make a local bump and using the existing fast
bump magnets for horizontal phase-space painting.
ACCSIM simulations for charge-exchange injection at
160 MeV have been investigated for both LHC and
CNGS beams. After optimizing the parameters that are
used for the space charge tracking routines, the results
of the simulations agree well with expectations,
signifying that the LHC ultimate and CNGS beams
may be provided with single PS Booster batches within
the required emittances. For assessment, simulation of
injection at 50 MeV for the current LHC beam has
been performed, yielding a fairly good agreement with
measured performance. Concurrently, similar chargeexchange injection simulations have been carried out
using an alternative programme developed at the
Rutherford Appleton Laboratory.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
136-546 - Beam Dynamics Challenges for Future
Circular Colliders
Frank Zimmermann (CERN, Geneva)
The luminosity of circular colliders rises with the beam
intensity, until some limit is encountered, mostly due to
head-on and long-range beam-beam interaction, due to
electron cloud, or due to conventional impedance
sources. These limitations can be alleviated, if not
overcome, by a proper choice of beam parameters and
by dedicated compensation schemes. Examples include
the alternating crossing at several interaction points,
electromagnetic wires, super-bunches, electron lenses,
clearing electrodes, and nonlinear collimation. I
illustrate the benefit from such mitigating measures for
the Tevatron, the LHC, the LHC Upgrade, the VLHC,
the super e+e- factories, or other projects, and I
describe related research efforts at FNAL, KEK, BNL and
CERN.
Type of presentation requested: This is an Invited Oral
Presentation
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
137-568 - Capture Loss of the LHC Beam in the CERN
SPS
Elena Shaposhnikova, Thomas Bohl, Trevor Paul Linnecar,
Joachim Tuckmantel (CERN, Geneva)
The matched voltage of the LHC beam at injection into the
SPS is 750 kV. However, even with RF feedback and feed
forward systems in operation, the relative particle losses on
the flat bottom for nominal LHC parameters with this
capture voltage can reach the 30% level. With voltages as
high as 2 MV these losses are still around 15% pushing the
intensity in the SPS injectors to the limit to obtain nominal
intensity beam for the LHC. Beam losses grow with
intensity and are always asymmetric in energy (lost particles
are seen main in front of the batch). The asymmetry can be
explained by the energy loss of particles due to the SPS
impedance which is also responsible for a non-zero
synchronous phase on the flat bottom leading to large gaps
between buckets. In this paper the measurements of the
dependence of particles loss on the beam and machine
parameters are presented and discussed together with
possible loss mechanisms.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
138-652 - Injection Schemes for Self Consistent Space
Charge Distributions
Viatcheslav V. Danilov, Stuart Henderson, Jeffrey Alan
Holmes, Michael Plum (ORNL/SNS, Oak Ridge, Tennessee),
Sarah M. Cousineau (ORNL/ASD, Oak Ridge, Tennessee)
This paper is based on recently found sets of self-consistent
2D and 3D time-dependent space charge distributions. A
subset of these distributions can be injection-painted into an
accumulator ring, such as Spallation Neutron Source Ring,
to produce periodic space charge conditions. The periodic
condition guarantees zero space-charge-induced halo growth
and beam loss during injection. Practical aspects of such
schemes are discussed, and simulations of a few specific
cases are presented.
Research sponsored by UT-Batelle, LLC, under contract no.
DE-AC05-00OR22725 for the U.S. Department of Energy
SNS is a partnership of six national laboratories: Argonne,
Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos,
and Oak Ridge
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
139-654 - Rotating Electromagnetic Field Trap for High
Temperature Plasma and Charge Confinement
Viatcheslav V. Danilov (ORNL/SNS, Oak Ridge, Tennessee)
This paper demonstrates that there exists a special
combination of oscillating electromagnetic fields capable of
trapping ultra high charge densities. Trapped particles
undergo stable motion when their frequencies of oscillation
are much higher than that of the ocillating field. Contrary to
conventional electromagnetic traps, the motion in this
dynamic trap is stable for arbitrarily high
electromagnetic field amplitudes. This, in turn, leads to
the possibility of using enormous electric and magnetic
fields from RF or laser sources to confine dense
ultrahigh temperature plasmas and particle beams.
Research sponsored by UT-Batelle, LLC, under
contract no. DE-AC05-00OR22725 for the U.S.
Department of Energy
SNS is a partnership of six national laboratories:
Argonne, Brookhaven, Jefferson, Lawrence Berkeley,
Los Alamos, and Oak Ridge
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
spread of 100 keV or better. According to computer
simulations the required cooling rates can be achieved by
electron cooling with an electron current of 1 A. The
conceptual design of an electron beam device which is based
on electrostatic acceleration of the electrons and their
transport in longitudinal magnetic fields into a cooling
section with a strong magnetic field of up to 0.5 T will be
presented. This design will allow cooling in the magnetized
regime in order to reach the required high cooling rates.
Some novel features for the generation and regulation of the
accelerating voltage and for the beam transport are
proposed.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
140-733 - Observation of Ultracold Heavy Ion
Beams with Micrometer Size Detected by Beam
Scraping
Markus Steck, Karl Beckert, Peter Beller, Bernhard
Franzke, Fritz Nolden (GSI, Darmstadt)
The existence of an ordered beam state for low
intensity, electron cooled heavy ion beams has been
evidenced by a sudden reduction of the momentum
spread. The detection of a similar effect in the
transverse degree of freedom by non-destructive
diagnostics is ruled out by the limited resolution of
beam profile detectors. A method to probe the
horizontal beam size of an electron cooled beam in a
dispersive section has been developed. It is based on
beam scraping and allows a resolution on the order of
micrometers. This good transverse resolution for the
cooled ion beam is achieved by precise changes of the
ion energy which is varied by changes of the electron
beam energy. The lower resolution limit due to power
supply ripple is estimated to be below 1 micrometer.
This method evidenced that the reduction of the
momentum spread by one order of magnitude coincides
with a reduction of the transverse beam emittance by 23 orders of magnitude, at least. A horizontal beam
radius of a few micrometer could be demonstrated for
electron cooled heavy ion beams with less than 1000
particles. This gives new evidence for the formation of
an ordered beam arranged as a linear string of ions.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
142-791 - ORBIT Benchmark of Space-charge-induced
Emittance Growth in the CERN PS
Sarah M. Cousineau (ORNL/ASD, Oak Ridge, Tennessee),
Elias Metral (CERN, Geneva), Jeffrey Alan Holmes
(ORNL/SNS, Oak Ridge, Tennessee)
Particle tracking codes provide an invaluable tool in the
design and operation of high intensity machines. An
important task in the development of these codes is the
validation of the space charge models through benchmark
with experimental data. Presented here are benchmarks of
the ORBIT particle tracking code with recent measurements
of space-charge-induced transverse emittance growth in the
CERN PS machine. Benchmarks of two experimental data
sets are performed: Integer resonance crossing, and
Montague resonance crossing.
SNS is managed by UT-Battelle, LLC, under contract DEAC05-00OR22725 for the U.S. Department of Energy
SNS is a partnership of six national laboratories: Argonne,
Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos
and Oak Ridge
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
141-734 - An Electron Cooling System for the
Proposed HESR Antiproton Storage Ring
Markus Steck, Karl Beckert, Peter Beller, Alexei
Dolinskii, Bernhard Franzke, Fritz Nolden (GSI,
Darmstadt), Vasily Parkhomchuk, Vladimir Borisovich
Reva, Alexander Skrinsky (BINP, Novosibirsk)
The HESR storage ring in the proposed new
international accelerator facility will provide high
quality antiproton beams for experiments with an
internal target. In order to achieve the design
luminosity for collisions with a hydrogen target
powerful beam cooling is required. For dedicated
experiments ultimate resolution is demanded.
Therefore it is foreseen to provide cooled antiproton
beams in the energy range 0.8-14 GeV with an energy
143-826 - Dynamics of the Electron Pinch and
Incoherent Tune Shift Induced by Electron Cloud
Elena Benedetto, Frank Zimmermann (CERN, Geneva)
When a proton bunch passes through an electron cloud, the
cloud electrons are attracted by the beam electric field; their
density strongly increases near the beam centre. This gives
rise to an incoherent proton tune shift, which depends on the
longitudinal and radial position within the bunch. We
present an analytical description of the 'electron pinch' and
the resulting proton tune shift, for a circular symmetry and a
Gaussian cloud. Benchmarking and extending the results by
computer simulations, we explore the effects of different
longitudinal beam profiles and of the nonlinear transverse
force.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
144-837 - Halo Budget and Beam Loss in the SNS
Accumulator Ring
Alexei V. Fedotov, Jie Wei (BNL, Upton, Long Island,
New York)
Beam loss becomes a serious issue for the highintensity operation of the SNS accumulator ring.
Understanding of various contributionsto beam halo
formation thus becomes very important. We review
major mechanisms of halo formation which contribute
to the halo budget. The necessary steps to reduce this
halo budget to an acceptable limit are discussed.
Work supported by the SNS through UT-Battelle, LLC,
under contract DE-AC05-00OR22725 for the U.S.
Department of Energy
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
145-844 - Studies of the Cooling Force in Various
Regimes
Alexei V. Fedotov, Ilan Ben-Zvi, Vladimir N Litvinenko
(BNL, Upton, Long Island, New York), Dan Abell,
David Bruhwiler, Richard Busby (Tech-X, Boulder,
Colorado)
The cooling times at high energy are significantly
longer than in conventional low-energy coolers. This
sets a very strict requirement on the accuracy of
cooling calculations. The first step toward an accurate
description of the cooling dynamics is obtaining a
reliable estimate of the friction force experienced by
ions during their interaction with the electron beam.
The magnetized cooling force was calculated from first
principles using direct numerical implementation of
Coulomb's law with the VORPAL code. Such an
approach allows benchmarking of various analytic
expressions for the friction force typically used in
cooling dynamics studies. The dependence of the
friction force on various parameters, such as magnetic
field strength in the cooling solenoid, electron and ion
beam temperatures, etc., was explored. Different
regimes were studied, including one where the force is
near its maximum, and another where the Coulomb
logarithm for cooling is small, limiting the applicability
of existing formulas.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
146-850 - High Energy Electron Cooling Dynamics
at RHIC
Alexei V. Fedotov, Ilan Ben-Zvi, Yury Eidelman,
Vladimir N Litvinenko (BNL, Upton, Long Island, New
York), Igor Meshkov, Anatoly Olegovich Sidorin,
Alexander Smirnov, Grigory Troubnikov (JINR,
Dubna, Moscow Region)
The project of high-energy electron cooling for RHIC
is presently underway at Brookhaven National
Laboratory. In such a regime, electron cooling has
many unique features and challenges. In addition to
some new aspects of cooling dynamics at high-energy,
required cooling times must be estimated with a
relatively higher degree of accuracy, compared to
present low-energy coolers. To address these issues, a
detailed study program of cooling dynamics based on
computer codes, specifically developed do address highenergy cooling issues, was launched at BNL. Here, we
present progress update of the high-energy cooling
dynamics studies. Some special features and aspects of
electron cooling relevant for colliders, such as effects of
rapid cooling of a beam core and accurate treatment of
intrabeam scattering for such cooled ion distributions are
also discussed.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
147-851 - Intensity Dependent Emittance Transfer
Studies at the CERN Proton Synchrotron
Elias Metral, Christian Carli, Massimo Giovannozzi, Michel
Martini, Rende Richard Steerenberg (CERN, Geneva),
Giuliano Franchetti, Ingo Hofmann (GSI, Darmstadt), Ji
Qiang (LBNL, Berkeley, California), Robert D Ryne
(LBNL/CBP, Berkeley, California)
An intensive study has been undertaken since the year 2002
to understand better the various high-intensity bottlenecks of
the CERN Proton Synchrotron machine. One of these
limitations comes from the so-called Montague resonance.
High-intensity proton synchrotrons, having larger horizontal
than vertical emittance, may suffer from this fourth-order
coupling resonance driven by space charge only. In
particular, such resonance may lead to emittance sharing
and, possibly, beam loss due to vertical acceptance
limitation. Experimental observations made in the 2002 and
2003 runs on the Montague resonance are presented in this
paper and compared with 3D particle-in-cell simulation
results and theoretical predictions.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
148-866 - THZ Emission Characteristics of BESSY II
Operated in a Dedicated Optics of a Positive and
Negative Momentum
Godehard Wustefeld, Joerg Feikes, Karsten Holldack, Peter
Kuske (BESSY GmbH, Berlin)
The electron storage ring BESSY II can be operated with a
strongly reduced momentum compaction factor (alpha). In
this dedicated optics mode the bunches become
longitudinally compressed and emit strongly enhanced,
coherent THz radiation (CSR)[*]. Different thresholds and
emission characteristics depending on the sign of alpha are
expected for the interaction of the bunch with the CSR and
the vacuum chamber. Bunch current dependend THz
intensity thresholds and THz power spectra for small alpha
values of equal magnitude but opposite sign are presented.
Funded by the Bundesministerium fuer Bildung und
Forschung and by the Land Berlin
* M. Abo-Bakr et al., Phys. Rev. Lett. 88, 254801 (2002).
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
149-933 - Oscillations of Mismatched Beams in
FODO Channels
Oscar A. Anderson (LBNL, Berkeley, California)
Strong space charge challenges the designers of
modern accelerators such as those used in Heavy Ion
Inertial Fusion. Simple, accurate design tools are useful
for predicting beam behavior, such as phase advances
and envelope oscillation periods, given the beam
emittance and charge and the lattice parameters. Along
with the KV beam model, the smooth approximation
[*] is often used. It is simple but not very accurate in
many cases. Although Struckmieir and Reiser [**]
showed that the stable envelope oscillations of
unbalanced beams could be obtained accurately, they
used a hybrid approach where the phase advances
sigma0 and sigma were already known precisely.
When starting instead with basic quantities-quadrupole dimensions, field strength, beam line
charge and emittance--the smooth approximation
formulas give substantial errors (10% or more). We
previously described an integration method [***] for
matched beams that yields fairly simple third-order
formulas for sigma0, sigma, beam radius and ripple.
Here we extend the method to include small-amplitude
mismatch oscillations. We derive a simple modification
of the smooth approximation formulas and show that it
improves the accuracy of the predicted envelope
frequencies significantly--for example, by a factor of
five when sigma0 is 83 degrees.
In part by Office of Fusion Energy, US DOE under
contract No. DE-AC03-76SF00098
* M. Reiser, Particle Accelerators 8, 167 (1978)
** J. Struckmeier and M. Reiser, Particle Accelerators
14, 227 (1984)
*** O. A. Anderson, Particle Accelerators 52, 133
(1996)
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
150-953 - New Abilities of Computer Code DeCA
Peter Gladkikh, Andrey Yurij Zelinsky (NSC/KIPT,
Kharkov)
In the paper the status and new abilities of computer
code package DeCA (Design of Cyclic Acclerators) are
described. The main effort of the code developers were
made to creation of software capable to simulate
intrabeam scattering effect and Compton scattering. In
addition modules for calculation of the second order
dispersion and momentum compaction factor were
developed.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
151-961 - An Interaction of Stored Ions with
Electron Target in Low Energy Electrostatic Ring
Evgeny Syresin (JINR, Dubna, Moscow Region),
Tetsumi Tanabe (KEK, Ibaraki), Koji Noda (NIRS,
Chiba-shi)
The KEK electrostatic ring is used for investigations of
molecular, bimolecular and DNA ions. The electron
target installed in this ring has same construction as
usual electron cooler. The interaction of stored ions with the
electrons increases the ion lifetime at electron cooling
caused by a suppression of the ion scattering on the residual
gas atoms. The proton lifetime of 2 s was increased in the
experiments by factor 2 at the electron cooling with the
electron beam current of 0.2 mA, the proton energy of 20
keV and the residual gas pressure of 0.04 nTorr. However
the electron-ion interaction can decrease the ion lifetime
caused by an excitation of the transverse instability
produced by an intensive electron beam. So in the KEK
electrostatic ring the proton lifetime is reduced to 1.7 s at
detuning of electron acceleration voltage from nominal
cooler value on 0.4 V. The simulation of electron cooling
and transverse instability of the light and DNA ions are
discussed in this report.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
152-968 - Beam Loss and Space Charge Effects in
JPARC Synchrotrons
Shinji Machida (KEK, Ibaraki)
High intensity synchrotrons such as JPARC rapid cycling
synchrotron (RCS) and main ring (MR) do have a stringent
beam loss specification. Collective effects due to space
charge is one of sources to create beam halo and eventually
beam loss. Mainly thanks to high computation power in last
few years, high performance simulations such as a whole
cycle tracking of 20 ms RCS acceleration become feasible.
Although it is still not clear if there is a dominant
mechanism that explains halo formation quantitatively,
collection of simulation results in various parameter space
gives a guideline to an operation of high intensity
sychrotrons. We will discuss simulation results up to date
and try to derive generalized features.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
153-1007 - Space Charge Effects in the Cooling Ion
Beam
Vladimir Vostrikov (BINP, Novosibirsk)
Design of particle accelerators with intense ion beams and
cooling requires careful control of space charge problems.
During the cooling of ion beam the betatron tune shifts are
increased. It can lead to resonance perturbations of particle
oscillation thus, limiting the achievable charge densities.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
154-1039 - Nonlinear Models for Dynamics of Highbrightness Beams
Michael G. Zeitlin, Antonina N. Fedorova (RAS/IPME, St.
Petersburg)
We consider a few reductions from nonlinear Vlasov-like
equations to rms/rate equations for second moments related
quantities (with or without additional equations or/and
constraints for energy and emittance). Our analysis is based
on variational--wavelet approach to rational (in dynamical
variables) approximations with possible related constraint
equations. It allows to control contributions to spectrum
from each scale of underlying multiscales and represent
solutions via multiscale nonlinear eigenmodes
expansions. Our approach provides the best
convergence properties of the corresponding exact
representations and does not use perturbations or/and
linearization procedures. Reduced algebraical structure
provides
the
pure
algebraical
control
of
stability/unstability scenario and appearance of
different type of behaviour (chaotic vs. localized
patterns) in space of parameters.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
155-1042 - Investigation of Parameters of an
Electron Beam from the Powerful High-voltage
Magnetron Guns with a Secondary-emission
Cathode.
Anatoly Nikolayevich Dovbnya, Nikolay Aizatsky,
Victor Boriskin, Nikolay Reshetnyak, Victor
Romas&#8217;ko, Tamara Semenets, Yury
Volkolupov, Valery Zakutin (NSC/KIPT, Kharkov)
The paper is devoted to investigations into the
development of a cathode unit for the 3 cm klystron
applied in medical therapeutic accelerators. The
investigations were carried out using a gun comprising
a copper cathode (40 mm in diameter, 70 mm length),
and a cylindrical anode (70 mm in diameter, 140 mm
length). The measurement of beam parameters was
performed by means of a sectionalized 8-channel
Faraday cup and a multichannel computer-aided
measuring system. The experiments have shown that
the beam generation is stable. The current instability of
beams falling at eight segments of the Faraday cup
during 16 voltage pulses following one after another
was ranging from ~2 to 3%. At a cathode voltage
amplitude of 50 kV and a magnetic field strength of
~1500 Oe this source forms a tubular beam with an
external diameter of 50 mm, an internal diameter of 44
mm and a beam current of ~50 A. The measured beam
charge distribution in azimuth has the nonuniformity
from 7 to 10%. The beam current pulse duration is
~8µs, the beam pulse power is ~2.5 MW.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
156-1068 - Study of Diffusion Process caused by
Beam-beam Interactions
Kazuhito Ohmi, Katsunobu Oide, Masafumi Tawada
(KEK, Ibaraki)
A system of colliding two beams is strong nonlinear in
multi-dimension. In such a system, a symplectic
diffusion called Arnold diffusion occurs, with the result
that the beams are enlarged and the luminosity is
degraded in circular colliders. We discuss the diffusion
seen in beam-beam inetraction at a circular accelerator,
especially finite crossing angle and/or x-y coupling
errors enhance the diffusion.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
157-1074 - Dissipation and Chaotic Mixing in Intense
Beams in the Presence of Skew Quadrupole Errors
Rami Alfred Kishek, Irving Haber, Hui Li (IREAP, College
Park, Maryland), Patrick G. O'Shea (IREAP, College Park,
Maryland; Maryland University, College Park, Maryland)
Skew quadrupole (rotational) errors introduce a high level of
complexity into the dynamics of intense charged particle
beams. For instance the standard x, y envelope equations
need be replaced by 10 moment equations that include the
cross-moments. Envelope mismatch oscillation frequencies
similarly bifurcate into a larger number of allowable modes.
Individual test particles trapped in such a potential are likely
to experience complicated orbits, and to resonate with the
rotational modes as well as the envelope modes. In order to
illuminate the complex dynamics taking place in skew
quadrupole systems, particles are tracked through linear as
well as self-consistent nonlinear potential wells with
quadrupole rotation errors. The implications of the study on
halo formation and equilibration mechanisms are discussed.
This work is funded by US Dept. of Energy under contracts
No. DE-FG02-94ER40855 and DE-FG02-92ER54178
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
158-1089 - Electron Cooling Experiments at HIMAC
Synchrotron
Koji Noda, Shinji Shibuya, Tomonori Uesugi (NIRS, Chibashi), Evgeny Syresin (JINR, Dubna, Moscow Region), Shiro
Ninomiya (RCNP, Osaka)
In the HIMAC synchrotron, the electron cooling
experiments have been carried out since 2000 in order to
develop new technologies in heavy-ion therapy and related
research. Among of them, especially, the cool-stacking
method has been studied to increase the intensity of heavy
ions such as Fe and Ni in order to study the risk estimation
of the radiation exposure in space. The simulation was
carried out in order to optimize the stacking intensity under
various the injection periods. In addition, the beam heating
by the RF-KO and the clearing the secondary ion in the
cooler were applied to avoid the instability occurred when
the beam density became high. We will report the
experiment results.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
159-1222 - Dynamics and Cooling of Modulated Bunches
in the Bend
Raphael Tumanyan (YerPhI, Yerevan)
The influence of the space charge field on the dynamics of
the particles of the bunch, which is moved in the bend
magnet, is calculated. It is shown, that such influence on the
energy of the particles of the modulated bunch cause in the
decreasing of the bunch energy spread, i.e. in the bunch
cooling. The conditions of the maximum cooling are found.
The attainable ordering of the bunch is investigated.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
160-1238 - Expected Performance and Beam-based
Optimization of the LHC Collimation System
Ralph Assmann, Eva Barbara Holzer, Jean-Bernard
Jeanneret, Verena Kain, Stefano Redaelli, Guillaume
Robert-Demolaize, Jorg Wenninger (CERN, Geneva),
Dobrin Kaltchev (TRIUMF, Vancouver)
The cleaning efficiency requirements in the LHC are 23 orders of magnitude beyond the requirements at other
super-conducting circular colliders. The achievable
ideal cleaning efficiency in the LHC is presented and
the deteriorating effects of various physics processes
and imperfections are discussed in detail for the
improved LHC collimation system. The longitudinal
distribution of proton losses downstream of the
betatron cleaning system are evaluated with a realistic
aperture model of the LHC. The results from simplified
tracking studies are compared to simulations with
complete physics and error models. Possibilities for
beam-based optimization of collimator settings are
described.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
161-1286 - Observation of a Fast Single Bunch
Transverse Instability on Protons in the SPS
Helmut Burkhardt, Gianluigi Arduini, Elena Benedetto,
Elias Metral (CERN, Geneva), Giovanni Rumolo (GSI,
Darmstadt)
The longitudinal impedance of the SPS has been
reduced significantly by hardware modifications over
the last years and the threshold for longitudinal
instabilities increased accordingly. We now observe a
fast transverse instability on high intensity single
bunches of low longitudinal emittance. The main
observed signature and the threshold dependence on
beam parameters is described and compared with
theoretical expectations and simulations.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
162-1287 - Investigation of Space Charge Effects
and Intrabeam Scattering for Lead Ions in the SPS
Helmut Burkhardt, Django Manglunki, Michel Martini,
Federico Roncarolo (CERN, Geneva), Giovanni
Rumolo (GSI, Darmstadt)
Space charge effects and intrabeam scattering usually
play a minor role in high energy machines like the SPS.
They can potentially become a limitation for the heavy
ion beams needed for the LHC at the injection plateau
in the SPS. Experimental studies on space charge
limitations performed on low energy proton beams in
the SPS will be described. Theoretical studies have
been performed to predict emittance growth times due
to intrabeam scattering using several different codes.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
163-1302 - Simulation Results on Cooling Times and
Equilibrium Parameters for Antiproton Beams at the
HESR
Alexei Dolinskii, Oliver Boine-Frankenheim, Bernhard
Franzke, Markus Steck (GSI, Darmstadt), Alexander
Bolshakov, Pavel Zenkevich (ITEP, Moscow), Anatoly
Olegovich Sidorin, Grigory Troubnikov (JINR, Dubna,
Moscow Region)
The High Energy Storage Ring HESR is part of the
"International Accelerator Facility for Ion and Antiproton
Beams" proposed at GSI. For internal target experiments
with antiproton beams in the energy range 0.8 GeV to 14.5
GeV a maximum luminosity of 5 inverse nbarn per second
and a momentum resolution on the order of 10 ppm have to
be attained. Electron cooling is assumed to be the most
effective way to counteract beam heating due to target
effects and intra-beam scattering. Cooling times and
equilibrium parameters have been determined by means of
three different computer codes: BETACOOL, MOCAC, and
PTARGET. The results reveal that the development of fast,
"magnetized" electron cooling with beam currents of up to 1
A and variable electron energies of up to 8 MeV in an
extremely homogeneous longitudinal magnetic field of up to
0.5 T is crucial to achieve the required equilibrium beam
parameters over the envisaged range of antiproton energies.
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
164-1312 - Lattice Design and Cooling Simulation at SLSR
Toshiyuki Shirai, Hicham Fadil, Shinji Fujimoto, Masahiro
Ikegami, Akira Noda, Takeshi Takeuchi, Hiromu Tongu
(ICR Kyoto, Kyoto), Hiromi Okamoto, Yosuke Yuri
(HU/AdSM, Higashi-Hiroshima), Evgeny Syresin (JINR,
Dubna, Moscow Region), Manfred Grieser (MPI-K
A compact ion cooler ring, S-LSR is under construction in
Kyoto University. The circumference is 22.557 m and the
maximum magnetic rigidity is 1 Tm. One of the important
roles of S-LSR is a test bed to examine the lowest
temperature limit of the ion beams using cooling techniques.
The ultimate case is a crystalline one. The ring optics of SLSR has a high super periodicity and a low phase advance to
reduce the beam heating from the lattice structure. S-LSR
has an electron beam cooling device and a laser cooling
system for Mg. The simulation results show the possible
limit of the ion beam temperature and the dependence on the
operating betatron tunes.
Advanced Compact Accelerator Development of Ministry of
Education, Culture, Sports, Science and Technology
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
165-1327 - Image-charge Effects on the Beam Halo
Formation and Beam Loss in a Small-aperture
Alternating-gradient Focusing System
Jing Zhou, Chiping Chen (MIT/PSFC, Cambridge,
Massachusetts)
The image-charge effects on an intense charged-particle
beam propagating through an alternating-gradient focusing
channel with a small aperture, circular, perfectly conducting
pipe are studied using a test-particle model. For a well-
matched elliptical beam with the KapchinskijVladimirskij (KV) distribution, it is found that halo
formation and beam loss is induced by nonlinear fields
due to image charges on the wall. The halo formation
and chaotic particle motion dependent sensitively on
the system parameters: filling factor of the quadrupole
focusing field, vacuum phase advance, beam
perveance, and the ratio of the beam size to the
aperture. Furthermore, the percentage of beam loss to
the conductor wall is calculated as a function of
propagating distance and aperture. The theoretical
results are compared with PIC code simulation results.
Work supported by the U.S. Department of Energy and
Air Force Office of Scientific Research
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
166-1399 - New Ideas for Muon Beam Cooling
Yaroslav Derbenev (Jefferson Lab, Newport News,
Virginia), Rolland Johnson (Muons, Inc, Batavia)
We report on new concepts for ionization cooling of
muon beams in a Neutrino Factory (NF) or Muon
Collider (MC). First, we achieve longitudinal
compression and cooling of the initial muon beam in
the helical channel using energy loss without RF reacceleration and then we achieve exceptional sixdimensional cooling with a continuous hydrogen gas
absorber. There are three more ideas on achieving an
additional MC cooling to make the transverse beam
emittances so small that fewer muons are needed to
achieve high luminosity. These concepts involve
transverse and longitudinal phase cooling using
parametric resonances in transport optics correlated
with absorber plates, and, finally repartition the
emittances using fast reverse emittance exchange with
large angle wedge absorbers to increase luminosity.
We estimate that these ideas imply MC transverse
emittances one or even two orders of magnitude
smaller than conventionally thought attainable with IC.
Conceptual schemes and numerical evaluations will be
presented.
U.S. Department of Energy Contract DE-AC0584ER40150
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
167-1407 - New Conceptds for High Energy
Electron Coling
Yaroslav Derbenev (Jefferson Lab, Newport News,
Virginia), Vadim Dudnikov (BTG, New York),
Viatcheslav V. Danilov (ORNL/SNS, Oak Ridge,
Tennessee)
We report on progress in conceptual development of
the proposed high luminosity (up to 1035/cm2s) and
efficient spin manipulation (using figure 8 boosters and
collider rings) Electron-Ion Collider at CEBAF based
on use of polarized 5-7 GeV electrons in
superconducting energy recovering linac (ERL with
circulator ring, kicker-operated) and 30-150 GeV ion
storage ring (polarized p, d, He3, Li and unpolarized
nuclei up to Ar, all totally stripped). Ultra-high
luminosity is envisioned to be achievable with short ion
bunches and crab-crossing at 1.5 GHz bunch collision rate
interaction points. Our recent studies concentrated on
characterization and simulation of beam-beam interaction,
preventing the electron cloud instability, calculating
luminosity lifetime due to Touschek effect in ion beam and
background scattering of ions, experiments on energy
recovery at CEBAF, and other. These studies have been
incorporated in the development of the luminosity calculator
and in formulating minimum requirements to the polarized
electron and ion sources.
This work was supported by the US Department of Energy
under Contract No DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
168-1409 - Concepts for Stacking Ion Beams
Overcoming Space Charge Limit on Emittance
Yaroslav Derbenev (Jefferson Lab, Newport News, Virginia)
We investigate ideas to accumulate and accelerate high
current low emittance proton and ion beams in boosters or
accumulator rings while overcoming the space charge
limitations. During injection to a ring, the beam is painted
(or transformed by other methods) into a large radius narrow
ring shape in phase space of each of the two planes while
keeping the phase space volume, i.e. true emittances, small.
The beam can be stacked to a high current value in such
state using stripping injection in booster or hollow beam
electron cooling in a small accumulator ring. After stacking
and accelerating to relativistic energies, the beam can be
returned to a normal spot shape using a special
transformation in the next transport line or in a booster with
RF resonance dipoles. Such techniques could be
incorporated with an ion facility of high luminosity electronproton or proton-proton collider with electron cooling.
Particles redistributions in phase space of betatron and
synchrotron oscillations can also be used for increase of the
threshold intensity of the electron cloud and transverse twostream instability.
This work was supported by the US Department of Energy
under Contract No DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [D03] High Intensity - Incoherent
Instabilities, Space Charge, Halos, Cooling
169-235 - Initial-Value Approach to the Theories of
Resonances and Collective Effects
Toshio Suzuki (KEK, Ibaraki)
Initial-value approach by computers is a modern method of
analyzing non-linear problems. Since we can obtain
analytical solutions in linear cases and in perturbation
theories, we study similarities between resonace effects and
and collective beam instabilities.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
170-416 - Single-bunch Electron Cloud Effects in
the GLC/NLC and US-cold Beam Deliver Systems
and Bunch Compressor System
Mauro Torino Francesco Pivi, Tor Raubenheimer
(SLAC/NLC, Menlo Park, California), Daniel Bates,
Arthur Chang, David Chen (SLAC, Menlo Park,
California)
In the beam pipe of the Beam Delivery System (BDS)
and Bunch Compressor system (BCS) of a linear
collider, ionization of residual gasses and secondary
emission may lead to amplification of an initial
electron signal during the bunch train passage and
ultimately give rise to an electron-cloud. A positron
beam passing through the linear collider beam delivery
may experience unwanted additional focusing due to
interaction with the electron cloud. This typically leads
to an increase in the beam size at the interaction point
(IP) when the cloud density is high. Interaction with
the electron cloud in the bunch compressor could also
potentially cause an instability. This paper examines
the severity of the electron cloud effects in the BCS
and BDS of both the GLC/NLC and US-Cold linear
collider design through the use of specially developed
simulation codes. An estimate of the critical cloud
density is given for the BDS and BCS of both designs.
Work supported by Department of Energy contract DEAC03-76SF00515
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
171-455 - Electron Cloud Build up in Coasting
Beams
Giovanni Rumolo (GSI, Darmstadt), Giulia Bellodi
(CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon), Frank
Zimmermann (CERN, Geneva), Kazuhito Ohmi (KEK,
Ibaraki)
Electrons could in principle accumulate in the potential
of coasting beams of positively charged particles until
a balance between the beam force and space charge
force from the electrons is reached. But the continuous
interaction between a non-ideal perturbed coasting
beam and the cloud of electrons being trapped by it,
together with the reflection and secondary emission
processes at the inner pipe wall, can alter this picture
and cause a combined cloud or beam transverse
instability long before the concentration of electrons
reaches the theoretical equilibrium value. The issue is
addressed in this paper by means of combined build-up
and instability simulations carried out with the
HEADTAIL code.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
172-472 - Beam Instabilitiy Studies of BEPC and
BEPCII
Jiuqing Wang, Zhiyuan Guo, Yudong Liu, Qing Qin,
zheng zhao, Demin Zhou (IHEP Beijing, Beijing)
BEPC has been well operated for more then 10 years,
and it will be upgraded to a double ring electron
positron collider using the existing tunnel, namely
BEPCII. This paper describes the recent studies on
beam instabilities in BEPC for the improvement of its
performance as well as for BEPCII. The instabilities caused
by impedance and two-stream effect are investigated. The
experimental and simulation results are reported.
Work supported by the Chinese National Foundation of
Natural Sciences, contracts 10275079-a050501 and
10375076-a050501
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
173-530 - A Cure for Multipass Beam Breakup in
Recirculating Linacs
Byung Chel Yunn (Jefferson Lab, Newport News, Virginia)
We investigate a method to control the multipass dipole
beam breakup instability in a recirculating linac including
energy recovery. Effectiveness of an external feedback
system for such a goal is shown clearly in a simplified
model. We also verify the theoretical result with a
simulation study.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
174-564 - Electron-cloud Build-up Simulations and
Experiments at CERN
Frank Zimmermann, Gianluigi Arduini, Vincent Baglin,
Thomas Bohl, Berthold Jenninger, Jos&#233; Miguel
Jimenez, Jean-Michel Laurent, Francesco Ruggiero, Daniel
Schulte (CERN, Geneva)
We compare the predications of electron-cloud build-up
simulations with measurements at the CERN SPS.
Specifically, we compare the electron flux at the wall,
electron-energy spectra, heat loads, and the spatial
distribution of the electrons for two different bunch
spacings, with variable magnetic fields, and for several
chamber temperatures and associated surface conditions.
The simulations employ a modified, improved version of the
ECLOUD code. The main changes are briefly described. We
finally present updated simulation results for the heat load in
the cold LHC arcs.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
175-576 - Energy Loss of a Single Bunch in the CERN
SPS
Elena Shaposhnikova, Thomas Bohl, Trevor Paul Linnecar,
Joachim Tuckmantel (CERN, Geneva)
The dependence of energy loss on bunch length was
determined experimentally for a single proton bunch in the
SPS at 26 GeV/c. This was done from measurements of the
synchronous phase as a function of intensity for different
capture voltages. The results are compared with the
expected dependence calculated from the resistive part of
the SPS impedance below 1 GHz. Two impedance sources,
the cavities of the 200 MHz RF system and the extraction
kickers, give the main contributions to particle energy loss
in very good agreement with experiment. The results
obtained allow a better understanding of some mechanisms
leading to capture loss of the high intensity LHC beam in
the SPS.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
176-578 - Resistive Wall Impedance and
Wakefunction with Inductive Bypass
Alexander Koschik, Elias Metral, Luc Vos (CERN,
Geneva)
We analyze the resistive wall impedance with an
"inductive bypass" due to alternate current paths in the
outer vacuum chamber proper. Also the corresponding
wake function has been obtained which is useful for the
simulation of beam stability in the time domain.
Results are presented for the LHC.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
177-583 - Wakefield Calculations for TTF-II
Igor Zagorodnov, Thomas Weiland (TEMF,
Darmstadt), Martin Dohlus (DESY, Hamburg)
In this paper we estimate long- and short-range wake
functions for new elements to be used in TESLA Test
Facility (TTF) - II. The wake potentials of the LOLAIV structure and the 3rd harmonic section are
calculated numerically for very short bunches and
analytical approximations for wake functions in short
and long ranges are obtained by fitting procedures
based on analytical estimations. The numerical results
are obtained with code ECHO for high relativistic
Gaussian bunches with RMS deviation up to 0.015
mm. The calculations are carried out for the complete
structures (including bellows, rounding of the irises
and the different end cell geometries) supplied with
ingoing and outgoing pipes. The low frequency spectra
of the wake potentials is calculated using the PronyPisarenko method.
work supported in part by the Deutsche
Forschungsgemeinschaft under contract WE1239/22
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
178-605 - Equilibrium Longitudinal Distribution for
Localized Regularized Inductive Wake
Stefania Petracca, Theo Demma (U. Sannio,
Benevento), Kohji Hirata (GUAS, Kanagawa)
In a recent paper [*] we have shown that a localized
wake assumption and the Gaussian approximation for
the longitudinal beam distribution function can be used
to understand the nature of the stationary solutions for
the inductive wake, by comparison between the
resulting map and the Haissinski equation, which rules
the (less realistic) case of a uniformly distributed
wake. In particular we showed the non-existence of
solutions of Haissinski's equation when the inductive
wake strength exceeds a certain threshold [**] to
correspond to the onset of chaos in the map evolving
the moments of the beam distribution from turn to
turn. In this paper we use the same formalism to
confirm that as noted in [**] for Haissinski's equation,
a steady state solution for the longitudinal phase space
distribution function always exists if a physically
regularized inductive wake, which satisfies an obvious
causality condition, is used.
* S. Petracca and Th. Demma, Proc. of the 2003 PAC,
IEEE Press, New York, 2003, ISBN 0-7803-7739-9, p.2996.
** Y. Shobuda and K. Hirata, Part. Accel. vol. 62, 165
(1999).
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
179-610 - Ectromagnetic Fields in the Beam Liner for a
Coaxial LHC-like Ring
Stefania Petracca, Rocco Paolo Croce, Theo Demma (U.
Sannio, Benevento)
We use the general solution [*] describing the
electromagnetic field in the toroidal region between the
beam liner and the cold bore to compute consistently the
field in the liner for an LHC-like ring.
* S. Petracca and Th. Demma, Proc. of the 2003 PAC, IEEE
Press, New York, 2003, ISBN 0-7803-7739-9, p.2999
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
180-612 - Electromagnetic Fields of an Off-axis Bunch in
a Circular Pipe with Finite Conductivity and Thickness
Stefania Petracca, Rocco Paolo Croce, Theo Demma (U.
Sannio, Benevento)
The electromagnetic field produced by a bunched beam in a
circular pipe is usually computed under the assumption that
the field penetration(skin depth) is far less than the wall
thickness. Chao [*] gave a formula which exploits the wall
thickness, but his result is restricted to the monopole term.
Piwinski [**] treated the case of a metal coated ceramic
wall, when the coating thickness is much smaller than the
skin-depth, but his analysis is also limited to the monopole
term.In this paper we solve the problem in full generality, by
providing an exact (Green's functions) solution for the field
of an off-axis point particle running at constant velocity in a
circular pipe with finite wall conductivity and thickness.
* A.W. Chao, Phys. of Collective Beam Instab. in High En.
Accel., Wiley,1993
** S. Piwinski, DESY 1972/72
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
181-613 - Wake Fields of Bunched Beam in Rings with
Lossy Walls of Finite Thickness
Stefania Petracca, Rocco Paolo Croce, Theo Demma (U.
Sannio, Benevento)
The general exact solution exploited [*] is applied,
introducing suitable dimensionless parameters, and using
appropriate asymptotic limiting forms, to compute the wake
field multipoles for the different paradigm cases of LHC and
DAPHNE.
* R. P. Croce, Th. Demma, S. Petracca "Electromagnetic
Fields of an Off-axis Bunch in a Circular Pipe with Finite
Conductivity and Thickness", these proceedings
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
182-615 - Modified Polarizabilities and Wall
Impedance for Perforated Beam Pipe
Stefania Petracca, Theo Demma (U. Sannio,
Benevento)
We extend previous results [*] concerning the modified
polarizability of (electrically small) holes/slots in the
wall of a circular beam liner surrounded by a coaxial
circular tube to the most general liner and cold bore
geometries. We obtain an equivalent wall impedance to
describe the electromagnetic boundary conditions at
perforated walls for this most general case, and use a
general perturbational approach [**] for computing the
pertinent longitudinal and transverse coupling
impedances.
* R.L. Gluckstern, CERN SL 92-06 (AP), 1992,
CERN SL 92-31 (AP), 1992; R.L. Gluckstern, B.
Zotter, CERN SL 96-56 (AP), 1996.
** S. Petracca, Part. Acc., {\bf 50}, 211, 1995; id.,
Phys. Rev. E, 60 (3),1999.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
183-616 - Localizing Impedance Sources from
Betatron-phase Beating in the CERN SPS
Frank Zimmermann, Gianluigi Arduini, Christian Carli
(CERN, Geneva)
Multi-turn beam-position data recorded after beam
excitation can be used to extract the betatron-phase
advance between adjacent beam position monitors
(BPMs) by a harmonic analysis. Performing this
treatment for different beam intensities yields the
change in phase advance with current. A local
impedance contributes to the average tune shift with
current, but, more importantly, it also causes a
mismatch and phase beating. We describe an attempt to
determine the localized impedance around the SPS ring
by fitting the measured betatron phase shift with
current at all BPMs to the expected impedance
response matrix.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
184-621 - Coherent and Incoherent Effects of the
Impedance Modelisation of the ESRF-Ring
Compared to Single Bunch Tune-shifts
Thomas Friedrich Guenzel (ESRF, Grenoble)
In single bunch the detuning of the transverse modes
m=0 and m=-1 are calculated on the base of a common
impedance model obtained from element-wise
wakefield calculation. As the vacuum chambers of the
ESRF storage ring have notably flat cross sections
incoherent effects have an impact on the tune shifts as
well as coherent effects. The results are compared to
measurements and discussed.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
185-626 - A Review of Collective Effects in the LHC
Francesco Ruggiero, Elena Benedetto, Werner Herr,
Alexander Koschik, Elias Metral, Daniel Schulte, Elmar
Vogel, Luc Vos, Frank Zimmermann (CERN, Geneva),
Hiroshi Tsutsui (SHI, Tokyo)
We present a revised impedance budget for the LHC,
including a significant resistive wall contribution from the
collimation system, and review transverse instabilities
driven by conventional wakefields and by the electron
cloud. We then discuss stabilisation strategies based on
chromaticity control, feedback system, and Landau damping
by the incoherent tune spread associated with lattice
octupoles and long range beam-beam encounters. Finally we
address beam-beam limitations, heat loads, emittance
preservation, and machine performance.
CERN, Geneva, Switzerland
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
186-687 - Investigation of Microwave Instability on
Electron Storage Ring TLS
Min-Huey Wang (NSRRC, Hsinchu), Alex Chao (SLAC,
Menlo Park, California)
With the planned installation of a superconducting rf
system, the new operation mode of TLS, the electron storage
ring at NSRRC, is expected to double the beam intensity.
Several accelerator physics topics need to be examined. One
of these topics concerns the beam instability of single-bunch
longitudinal microwave instability. We consider different
approaches to measure the effective broad band impedance.
We compare these measurement results with each other and
to the old data [*]. The new measurements of effective
broad band impedance are higher than the old measurement
since between these two sets of measurements several
narrow gap insertion devices were installed into the storage
ring. We calculate the threshold current of microwave
instability with a mode-mixing analysis code written by Dr.
K. Oide of KEK [**]. We also develop a multi-particle
tracking code to simulate the instability. The results of
simulation and measurement are compared and discussed.
We conclude that the doubling of beam current will not
onset the microwave instability even without a Landau
cavity to lengthen the bunch.
* M.H. Wang, et al.,"Longitudinal Beam Instability
Observation with streak Camera at SRRC", proceeding of
1996 European Particle Accelerator Conference, pp. 1120
** K. Oide, "Longitudinal Single-Bunch Instability in
Electron Storage Rings", KEK Preprint
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
187-723 - Simulation Calculations of Stochastic
Precooling
Inna Nesmiyan (National Taras Shevchenko University of
Kyiv, Kiev), Fritz Nolden (GSI, Darmstadt)
The process of longitudinal stochastic cooling is simulated
using a Fokker-Planck model. The model includes the
sensitivities of pick-up and kicker electrodes as calculated
from field theoretical models. The effect of feedback
through the beam is taken into account. Intra beam
scattering is treated as an additional diffusive effect. The
calculations cover the existing system of the ESR
storage ring at GSI as well as the cooling system for
secondary heavy ion and antiproton beams at the
proposed new accelerator facility. The paper discusses
the resulting cooling times. Requirements on the
system layout as amplification factors and electrical
power can be derived from the simulations.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
188-778 - Proposal for the Creation and Storage of
Long Bunches in the LHC
Heiko Damerau, Roland Garoby (CERN, Geneva)
Long bunches with a uniform longitudinal line density
held by barrier buckets are considered for a future
luminosity upgrade of the Large Hadron Collider
(LHC). With such bunches, the luminosity is
maximised for a fixed number of particles. Instead of
conventional barrier buckets, periodic barriers are
proposed. These are generated with multiple RF
harmonics (e.g. multiples of 40 MHz). A possible
scheme to create and hold long flat bunches in the LHC
is described, and the resulting gain in luminosity is
estimated.
Gesellschaft fuer Schwerionenforschung mbH (GSI),
Darmstadt, Germany
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
189-780 - Investigation of Cavity Induced
Longitudinal Coupled Bunch Mode Instability
Behaviour and Mechanisms
Robert Gerd Heine, Peter Hartmann, Arndt Haselhoff,
Holger Huck, Gerald Schmidt, Sebastian Strecker,
Thomas Weis (DELTA, Dortmund)
The narrowband impedances of RF-resonators in a
circular accelerator can drive coupled bunch mode CBI - instabilities which might spoil the overall beam
quality. Often, as in synchrotron radiation light sources
e.g. the instability does not lead to beam loss but to a
severe degradation of the source brilliance.
Investigations of longitudinal CBIs have been
performed at the DELTA storage ring with a single
DORIS-type cavity for future comparision with the
behaviour of a HOM-damped cavity to be tested at
DELTA. This resonator is presently developed and
built within an EU-collaboration. The beam was
deliberately driven into instability using the beam
current as well as the cavity temperature as individual
parameters. The instability characterisations at low
(542 MeV) and high (1,5 GeV) energy exhibit a
complex behaviour. The strength of the instability
measured by the bunch excursions in the case of
longitudinal CBIs, but also the spreading of the
instability across neighbouring modes depends on
parameters such as beam energy, resonant impedance
but also on counteracting mechanisms like synchrotron
radiation and Landau damping. The paper will cover
the experimental results together with estimations of
the influence and mechanism of Landau damping.
work partly supported by the EU under contract no. HPRICT-1999-50011
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
190-816 - The Effect of Inhomogeneous Magnetic Field
on Budker-Chirikov Instability
Yurii Golub (MRTI RAS, Moscow)
The two-beams electron - ion system consists of a
nonrelativistic ion beam propagating co-axially with a highcurrent relativistic electron beam in a longitudinal
inhomogeneous magnetic field. The effect of the
longitudinal inhomogeneous magnetic field on instability
Budker-Chirikov (BCI) in the system is investigated by the
method of a numerical simulation in terms of the kinetic
description of both beams. The investigations are
development of investigations in [*,**]. Is shown, when the
inhomogeneity magnetic field results in the decreasing of an
increment of instability Budker-Chirikov and the increasing
of length of propagation of a electron beam. Also is shown,
when take place the opposite result.
* Yu.Ya. Golub, N.E.Rozanov, Nuclear Instruments and
Methods in Physics Research, A358 (1995) 479
** Yu.Ya. Golub, Proceedings of EPAC 2002, Paris,
France, p.1497
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
191-820 - Simulated Emittance Growth due to Electron
Cloud for SPS and LHC Proton Beams.
Elena Benedetto, Daniel Schulte, Frank Zimmermann
(CERN, Geneva), Giovanni Rumolo (GSI, Darmstadt)
The emittance growth caused by an electron cloud is
simulated by the HEADTAIL code. The simulation result
depends on the number of beam-cloud "interaction
points"(IPs), the phase advance between the IPs, the number
of macro-particles used to represent beam and cloud, and on
the betatron tune. Simulations include a transverse feedback
system and, optionally, a large chromaticity, as employed in
actual SPS operation. Simulation results for the SPS are
compared with observations, and the emittance growth in
the LHC is computed as a function of the average electron
density.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
192-834 - RF Amplitude Modulation to Suppress
Longitudinal Coupled Bunch Instabilities in the SPS
Elmar Vogel, Thomas Bohl, Urs Wehrle (CERN, Geneva)
In the SPS, even after a considerable impedance reduction
including the removal of all RF cavities used for lepton
acceleration in the past, longitudinal coupled bunch
instabilities develop with an LHC beam of about one fifth of
the nominal bunch intensity. The nominal LHC beam is
stabilised using both, the 800 MHz Landau damping
cavities, in bunch shortening mode, and pre-emptive
emittance blow-up. An alternative method to increase the
synchrotron frequency spread and thus stabilise the beam is
amplitude modulation of the accelerating RF voltage. This
method might be especially suitable in accelerators without
a higher harmonic RF system, as will be the case in
LHC. The main results of recent studies using this
method in the SPS and considerations about its use in
LHC are presented.
CERN, Geneva, Switzerland
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
193-857 - Stability Diagrams for Landau Damping
with Two-dimensional Betatron Tune Spread from
Both Octupoles and Non-linear Space Charge
applied to the LHC at Injection
Elias Metral, Francesco Ruggiero (CERN, Geneva)
The joint effect of space-charge non-linearities and
octupole lenses is discussed for the case of a quasiparabolic transverse distribution of a monochromatic
beam. The self-consistent non-linear space-charge tune
shift corresponding to the above distribution function is
first derived analytically. The exact dispersion relation
is also given but not solved. Instead, noting that a good
approximation of the non-linear space-charge tune shift
is obtained considering only linear terms in the action
variables, the dispersion relation is solved analytically
in this approximate case. As expected, in the absence
of external (octupolar) non-linearities, the result of
Möhl and Schönauer is recovered: there is no stability
region. In the absence of space charge, the stability
diagrams of Berg and Ruggiero are also recovered.
Finally, the new result is applied to the LHC at
injection.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
194-862 - New Characteristics of a Single-bunch
Instability Observed in the APS Storage Ring
Chun-Xi Wang (ANL, Argonne, Illinois), Katherine
Harkay (ANL/APS, Argonne, Illinois)
In the Advanced Photon Source storage ring, a
transverse single-bunch instability has long been
observed that appears unique to this ring. Many of its
features have been previously reported. New results
have recently been obtained using beam centroid
history measurements and analysis. These preliminary
results provide more detailed information regarding the
characteristics of this instability and could provide
insight into the physics mechanism.
Work supported by U.S. Department of Energy, Office
of Basic Energy Sciences, under Contract No. W-31109-ENG-38
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
195-885 - Analysis of Electron Cloud at RHIC
Ubaldo Iriso, Michael Blaskiewicz, Angelika Drees,
Wolfram Fischer, Justin Gullotta, Ping He, HsiaoChaun Hseuh, Haixin Huang, Roger Lee, Loralie
Smart, Dejan Trbojevic, S.Y. Zhang (BNL, Upton, Long
Island, New York), Giovanni Rumolo (GSI, Darmstadt)
Pressure rises with high intense beams are becoming
the main luminosity limitation at RHIC. Observations
during the latest runs show beam induced electron
multipacting as one of the causes for these pressure rises.
Experimental studies are carried out at RHIC using devoted
instrumentation to understand the mechanism leading to
electron clouds. Possible cures using NEG coated beam
pipes and solenoids are experimentally tested. In the
following, we report the experimental electron cloud data
and analyzed the results using computer simulation codes.
Work supported by U.S. DOE under contract No DE-AC0298CH10886
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
196-898 - Studies of Current Dependent Effects at
ANKA
Anke-Susanne M&#252;ller, Ingrid Birkel, Erhard Huttel,
Francisco Perez, Montserrat Pont (FZK-ISS-ANKA,
Karlsruhe), Frank Zimmermann (CERN, Geneva)
The ANKA electron storage ring is operated at energies
between 0.5 and 2.5 GeV. A major requirement for a
synchrotron light source, such as ANKA, is to achieve a
high beam current. A multitude of mostly impedance related
effects depend on either bunch or total beam current. This
paper gives an overview over the various beam studies
performed at ANKA in this context, specifically the
observation of current dependent detuning, the dermination
of the bunch length change with current from a
measurement of the ratio between coherent and incoherent
synchrotron tune and an assessment of the effective
longitudinal loss factor from the current dependent
horizontal closed orbit distortion.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
197-899 - Investigation of Scraper Induced Wake Fields
at ANKA
Anke-Susanne M&#252;ller, Ingrid Birkel, Erhard Huttel,
Francisco Perez, Montserrat Pont (FZK-ISS-ANKA,
Karlsruhe), Frank Zimmermann (CERN, Geneva)
The ANKA synchrotron light source operates in the energy
range from 0.5 to 2.5 GeV. Typical requirements for light
sources include small beam sizes, large lifetimes and high
currents to provide the highest possible photon flux. The
understanding of impedance and instability related issues is
very important in order to improve the machine
performance, in particular when small aperture insertion
devices are installed that require protection by a scraper. In
the framework of an impedance survey the transverse and
longitudinal wake fields induced by a vertical scraper have
been measured and analysed. This paper reports the beam
observations and compares them with the expectation.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
198-918 - Suppression of Microbunching Instability
in the Linac Coherent Light Source
Zhirong Huang, Gennady Stupakov, James Welch,
Juhao Wu (SLAC, Menlo Park, California), Michael
Borland (ANL/APS, Argonne, Illinois), Paul Emma
(SLAC/ARDA, Menlo Park, California), Cecile
Limborg-Deprey (SLAC/SSRL, Menlo Park,
California)
A microbunching instability driven by longitudinal
space charge, coherent synchrotron radiation and linac
wakefields is studied for the linac coherent light source
(LCLS) accelerator system. Since the uncorrelated
(local) energy spread of electron beams generated from
a photocathode rf gun is very small, the microbunching
gain may be large enough to significantly amplify shot
noise fluctuations of the electron beam. The
uncorrelated energy spread can be increased by an
order of magnitude without degrading the free-electron
laser performance to provide strong Landau damping
against the instability. We study different damping
options in the LCLS and discuss an effective laser
heater to minimize the impacts of the instability on the
quality of the electron beam.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
199-937 - Direct Measurement of the Resistive
Wakefield in Tapered Collimators
Peter Tenenbaum (SLAC, Menlo Park, California),
Dmitry Onoprienko (Brunel University, Middlesex)
The transverse wakefield component arising from
surface resistivity is expected to play a major role in
the beam dynamics of future linear colliders. We report
on a series of experiments in which the resistive
wakefield was measured in a series of tapered
collimators, using the Collimator Wakefield beam test
facility at SLAC. In order to separate the contributions
of geometric and resistive wakefields, two sets of
collimators with identical geometries but different
resistivities were measured. The results are in
agreement with the theoretical prediction for the highresistivity (titanium) collimators, but in the case of
low-resistivity (copper) collimators the resistive
deflections appear to be substantially larger than
predicted.
Work supported by the US Department of Energy,
Contract DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
200-949 - Impedance Budget for the LCLS
Photoinjector Beamline
Cecile Limborg-Deprey (SLAC/SSRL, Menlo Park,
California), Karl Leopold Freitag Bane, Stephen
Michael Gierman, Zenghai Li, Cho-Kuen Ng (SLAC,
Menlo Park, California)
The LCLS Photoinjector beamline is now in the Design
and Engineering stage. The fabrication and installation
of this beamline is scheduled for the summer 2006. An
impedance budget has been computed to prevent
deterioration of the beam quality by wakefields and RF
effects while making engineering as simple and cost
effective as possible. For a perfect tuning, with ideal fields
and component alignment, the 80%-emittance at the end of
the injector beamline will be close to 0.9 mm.mrad. No
more than 0.1 mm.mrad emittance growth from field and
alignment errors will be tolerable in order to meet beam
quality requirements. The emittance growth will come from
static field errors for a maximum of 0.08 mm.mrad leaving a
margin of only 0.02 mm.mrad induced by wakefields and
RF perturbations. Transverse wakefields from bellows,
flanges, transition pieces and diagnostics tanks were
computed using ABCI and MAFIA. Results were compared
to analytical formulae when possible. RF perturbations in
the gun and in the accelerating structures were computed
using S3P. The perturbations were then integrated into
PARMELA computations to calculate emittance growth.
This work was supported by US Department of Energy,
contract No. DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
201-1033 - Confinement / Fusion of States in Plasma
Kinetics
Michael G. Zeitlin, Antonina N. Fedorova (RAS/IPME, St.
Petersburg)
An efficient numerical-analytical approach is proposed for
analysis
of
complex
collective
dynamics
in
accelerator/plasma physics models based on the full
hierarchy of kinetic equations (BBGKY-like systems of
equations). Our calculations are based on variational and
multiresolution approaches in the basis of polynomial tensor
algebras of various localized bases. We construct the
representation for hierarchy of distribution functions and
dynamical variables via the exact multiscale decomposition
in high-localized nonlinear eigenmodes. The corresponding
cut-off of infinite hierarchy, reductions to finite dimensional
subsets and accuracy of calculations are based on the new
multiscale metric structure of the whole Fock-like space of
all distribution functions. We demonstrate the possibility of
the existence of energy confinement/fusion in the small
regions of the phase space (waveleton configurations).
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
202-1037 - Multi-pass Beam-breakup: Theory and
Calculation
Ivan Bazarov (Cornell University, Ithaca, New York), Georg
Hoffstaetter (LEPP, Ithaca, New York)
Multi-pass, multi-bunch beam-breakup (BBU) has been long
known to be a potential limiting factor for the current in
linac-based recirculating accelerators. New understanding of
theoretical and computational aspects of the phenomenon
are presented here. We also describe a detailed simulation
study of BBU in the proposed 5 GeV Energy Recovery
Linac light source at Cornell University which is presented
in a separate contribution to this conference.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
203-1070 - Ep Instability in a Coasting Beam
Kazuhito Ohmi, Takeshi Toyama (KEK, Ibaraki),
Giovanni Rumolo (GSI, Darmstadt)
ep instability is discussed for a coasting beam
operation of J-PARC 50 GeV Main Ring. Our previous
study (PAC2003) was focussed only ionization
electron. We now take into account electrons created at
the chamber wall due to proton loss and secondary
emission with higher yield than ionization.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
204-1117 - Growth and Suppression Time of an Ionrelated Vertical Instability
Tsukasa Miyajima, Yukinori Kobayashi, Shinya
Nagahashi (KEK, Ibaraki)
In the KEK Photon Factory electron storage ring, a
vertical instability has been observed in a multi-bunch
operation mode. The instability can be suppressed by
octupole magnetic field in routine operation. Since the
instability depends on a vacuum condition in the ring,
it seems that it is an ion-related phenomenon. In order
to study this instability, we measured the growth and
the suppression time of it with the pulse octupole
magnet system, which can produce the octupole field
with rise and fall time of around 1.2msec. We obtained
the result that the instability was grown slowly
compared with to suppress it, and the growth time
depended on the fill pattern of the bunch train and the
beam current per bunch.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
205-1151 - Measurement of Vertical Quadrupole
Frequencies in the Photon Factory Storage Ring
Shogo Sakanaka, Toshiyuki Mitsuhashi, Takashi Obina
(KEK, Ibaraki)
We measured the frequencies of vertical quadrupole
oscillations in the 2.5-GeV Photon Factory storage ring
at KEK. The measured vertical quadrupole tunes
showed remarkable dependence of about -7.5E-5/mA
on the bunch current. This contrasts with our previous
result of about +4.8E-5/mA (presented in PAC2003)
for the horizontal quadrupole tune shift. These results
will suggest that the transverse wake forces in a
quadrupolar mode contribute significantly to the
transverse motions of particles in the Photon Factory
storage ring.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
206-1165 - Design of a Third Harmonic
Superconducting RF System at PLS
Eun-San Kim, Myung-Hwan Chun, Hyung-Gyun Kim,
Kyungryul Kim, In-Soo Park, Young-Uk Sohn, Jaeseok
Yang (PAL, Pohang)
A superconducting third harmonic rf system has been
designed in the PLS to raise beam lifetime. Expected
beam lifetimes verse beam emittance and operational
beam current are presented.
A multibunch
multiparticle tracking simulation is performed to investigate
energy spread, bunch-lengthening and beam instabilities due
to the rf cavities. The parameters of the designed rf cavity,
designed cryogenic system and estimation of heat load are
also presented.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
207-1187 - Vertcal Effective Impedance Measurements
at ESRF
Thomas Perron, Laurent Farvacque, Eric Plouviez (ESRF,
Grenoble)
Transverse impedance increase due to installation of low
gap vacuum chambers is a general effect observed in
synchrotron light sources. ESRF has been sensitive to this
increase of impedance, as its single bunch threshold has
dramatically decreased. This paper presents a method based
on closed orbit distortion measurements, witch allows to
measure locally the vertical effective impedance. Results of
measurements performed on low gap vacuum chambers and
in-vacuum ondulators are presented. As an extension to this
experiment, a new global method is discussed. This method,
also based on closed orbit measurement allows measuring
simultaneously all areas of high impedance in the machine
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
208-1194 - Higher Order Modes in the New 100 and 500
MHz Cavities at MAX-lab
Hamed Tarawneh, &#197;ke Andersson, Marlene
Bergqvist, Mathias Brandin, Mikael Eriksson, Lars
Malmgren (MAX-lab, Lund)
The MAX-II electron storage ring operates exclusively in
multi-bunch mode with all buckets filled. Damping of the
longitudinal higher order mode (HOM) instabilities has
successfully been provided by passive third harmonic 1.5
GHz cavities. With a new RF employing three 100 MHz
capacity loaded cavities and a fifth harmonic Landau cavity
installed, a study of the HOM impedances, and related
threshold instability currents, is necessary. Measurements
and calculations so far, are being presented.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
209-1275 - Study of the Impact of Resistive-wall
Impedance on SOLEIL
Ryutaro Nagaoka (SOLEIL, Gif-sur-Yvette)
The presence of low-gap chambers for insertion devices,
along with a relatively small vertical gap of 25 mm chosen
for the standard vacuum chambers, implies a significant
influence of the resistive-wall on the beam in the future
SOLEIL storage ring. A systematic approach was taken to
quantify the net contribution by taking into account all local
variations of the non-circular chamber cross-sections as well
as beta functions. Low multibunch instability thresholds
were found in both transverse planes, indicating the
necessity of cures, by means of transverse feedback and/or
chromaticity shifts. An effort was made to evaluate the
effect of metallic coating, particularly that of NEG, which
was adopted in all straight sections. The dependence on both
resistivity and thickness of NEG was followed. It is
found that, the NEG coating nearly doubles the reactive
part of the impedance in the frequency range seen by
the beam. Implication on the reduction of the
transverse mode-coupling instability threshold is
discussed. Incoherent tune shifts arising from the noncircular chamber cross-section were also evaluated,
including a non-negligible NEG contribution in the
short-range wakes.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
210-1276 - Numerical Evaluation of Geometric
Impedance for SOLEIL
Ryutaro Nagaoka (SOLEIL, Gif-sur-Yvette)
Good knowledge and minimisation of the coupling
impedance is of great importance for the future storage
ring SOLEIL, envisaged to operate in both high current
multibunch and high bunch intensity modes. Threedimensional computations of the geometric impedance
of various vacuum chamber components have been
made with the code GdfidL, which allows parallel
processing with a cluster of computers, rendering the
computation with a small mesh size and a long
integrated distance feasible. Many treated objects were
found to exhibit large asymmetry in the two transverse
planes, as well as resonant behaviour at high
frequencies, both of which being non-straightforward
to follow with the conventional analytical methods and
2-dimensional calculations. In particular, strongly
trapped modes found for the flange impedance resulted
in an unacceptably low vertical multibunch instability
threshold, which urged a modification of the original
cavity-like structure. The dependence of the dipole
chamber impedance on the vertical slot size was
followed to determine the optimal slot opening.
Characteristics of the total broadband impedance
obtained, along with relative contributions are also
presented.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
211-1355 - Curvature-induced Bunch Selfinteraction for an Energy Chirped Bunch in
Magnetic Bends
Rui Li (Jefferson Lab, Newport News, Virginia)
In a linear electron accelerator where high peak current
is required, bunch compression is often achieved by
sending an energy-chirped bunch through a magnetic
chicane. The curvature-induced bunch collective
interaction in a magnetic chicane can be studied using
effective forces in the canonical formulation of the
coherent synchrotron radiation (CSR) effect. In this
paper, the effective CSR forces or impedances are
analyzed for an energy-chirped bunch with high
frequency longitudinal perturbation. The modification
of the behavior of the longitudinal effective CSR
impedance in magnetic bends from its steady-state linebunch counterpart is found as a result of the energychirping induced longitudinal-horizontal correlation of
the bunch distribution in dispersive regions. The
implication of this modification of the effective impedance
on the longitudinal instability of a bunch under compression
is also studied.
This work was supported by the U.S. Dept of Energy under
Contract No. DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
212-1372 - Effect of Dark Currents on the Accelerated
Beam in an X-band Linac
Valery Dolgashev (SLAC/ARDA, Menlo Park, California),
Karl Leopold Freitag Bane, Gennady Stupakov, Juhao Wu
(SLAC, Menlo Park, California), Tor Raubenheimer
(SLAC/NLC, Menlo Park, California)
X-band accelerating structures operate at surface gradients
up to 120-180 MV/m. At these gradients, electron currents
are emitted spontaneously from the structure walls ("dark
currents") and generate additional electromagnetic fields
inside the structure. We estimate the effect of these fields on
the accelerated beam in a linac using two methods: a
particle-in-cell simulation code MAGIC and a particle
tracking code. We use the Fowler-Nordheim dependence of
the emitted current on surface electric field with field
enhancement factor beta. In simulations we consider
geometries of traveling wave structures that have actually
been built for the Next Linear Collider project.
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
213-1373 - Estimation of Electron Cloud in RHIC
Lanfa Wang, Ping He, Jie Wei (BNL, Upton, Long Island,
New York)
Electron cloud due to beam induce multipacting is suspected
to be one of the source of pressure rises in RHIC. This paper
estimates the possible electron cloud in RHIC. Various
parameters related electron multipacting has been
investigated.
work performed under the auspices of the U.S Deparment
Energy
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
214-1379 - Linear Vlasov Analysis for Stability of a
Bunched Beam
Robert Warnock, Gennady Stupakov (SLAC, Menlo Park,
California), Marco Venturini (LBNL, Berkeley, California),
James A. Ellison (UNM, Albuquerque, New Mexico)
We study the linearized Vlasov equation for a bunched
beam subject to an arbitrary wake function. Following Oide
and Yokoya, the equation is reduced to an integral equation
expressed in angle-action coordinates of the distorted
potential well. Numerical solution of the equation as a
formal eigenvalue problem leads to difficulties, because of
singular eigenmodes from the incoherent spectrum. We
rephrase the equation so that it becomes non-singular in the
sense of operator theory, and has only regular solutions for
coherent modes. We report on a code that finds thresholds of
instability by detecting zeros of the determinant of the
system as they enter the upper-half frequency plane, upon
increase of current. Results are compared with a time-
domain integration of the nonlinear Vlasov equation,
and with experiment, for a realistic wake function for
the SLC damping rings.
U. S. Department of Energy constracts DE-AC0376SF00515, DE-AC03-76SF00098, and DE-FG0399ER41104
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
215-1384 - Resistive Wall in the Regime of
Anomalous Skin Effect
Boris Podobedov, Jiunn-Ming Wang (BNL/NSLS,
Upton, Long Island, New York)
Resistive-wall wake functions and impedances have
been extensively studied by many authors. These
treatments are usually limited to the regime of normal
skin effect, and therefore do not describe correctly the
resistive wall contributions of metallic vacuum
chamber components at cryogenic temperatures. With
the recent emergence of small-gap super-conducting
undulators as a possible candidate to generate tunable
hard-x-ray photons, there is a need to accurately
calculate their effects on beam dynamics, as well as to
calculate the resistive-wall generated heat. Starting
with the well-known expressions for the surface
impedance in the extreme anomalous skin effect
regime, we derive most of the resistive wall related
concepts commonly used in accelerators, such as wake
functions, wake potentials, loss factors, etc. We discuss
the short-range and long-range wakefield regimes and
give examples for beam-induced heat, beam-induced
energy spread, and resistive wall instability due to
small-gap
superconducting
undulators
under
consideration for the NSLS-II light source at BNL.
Work supported by US DOE
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
216-1413 - Beam-beam Simulations for an Electronlight Ion Collider
Kevin Beard, Yaroslav Derbenev, Geoffrey Arthur
Krafft, Rui Li, Lia Merminga, Byung Chel Yunn,
Yuhong Zhang (Jefferson Lab, Newport News,
Virginia)
One of the most outstanding issues concerning the
luminosity of a linac-on-ring electron-light ion collider
(ELIC) is the beam-beam effect. A simulation code,
SWARM, previously used to model beam-beam effects
of the e+ e- collisions in a linac-ring collider,[*] was
modified into SWARMC for the beam-beam effects in
the linac-ring electron-ion collider. In this paper we
present simulation results on the stability limits using
recent ELIC design parameters. This study also
includes circulator ring and flat beams for the design.
This work was supported by the U.S. Dept of Energy under
Contract No. DE-AC05-84ER40150
* Strong-strong Simulation on the Beam-Beam Effect in a
Linac-Ring B factory, R. Li and J. J. Bisognano, Phys. Rev.
E 48, 3965-3979 (1993)
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
217-1460 - Emittance Control for very Short Bunches
Karl Leopold Freitag Bane (SLAC, Menlo Park, California)
Many recent accelerator projects call for the production of
high energy bunches of electrons or positrons that are
simultaneously short, intense, and have small emittances.
Two examples of such projects are linear colliders, such as
the GLC/NLC, and Self-Amplified Spontaneous Emission
(SASE) FEL's, such as the Linac Coherent Light Source
(LCLS). A major challenge in such projects is keeping in
check forces that increase short bunch emittances in
accelerator components, such as: wakefields of accelerator
structures, collimators, and surface roughness, and coherent
synchrotron radiation (CSR). We describe such forces and
their control.
Work supported by Department of Energy contract
DE--AC03--76SF00515
Type of presentation requested: This is an Invited Oral
Presentation
Classification: [D04] Instabilities - Processes, Impedances,
Countermeasures
218-1490 - Dipole Mode Study of RDDS1 Accelerating
Structure Using an Off-Axis Wire Measurement
Nicoleta Baboi (SLAC/ARDB, Menlo Park, California),
Gordon B Bowden, Roger Jones, James R. Lewandowski,
Juwen W Wang (SLAC/ARDA, Menlo Park, California)
Wakefields in accelerating structures can cause emittance
dilution in linear colliders. The constituent modes of the
wakefields have been measured with particle beams and
these have been found to be well predicted by a spectral
function method [*]. However, bench-top measurements are
desirable, as they are more efficient and do not require a
particle beam. One such method is the wire method
[**,***], which has been used in the past for measuring the
impedance of many accelerator components. At SLAC a
set-up has been designed and fabricated, which uses a single
wire to investigate dipole modes in accelerating structures
for the NLC (Next Linear Collider). Individual modes can
be isolated and their impedance calculated from fits of
experimental values of S21 as a function of frequency for
each wire position. The frequency of the unperturbed
modes can be obtained in the limit of the centered wire,
where the perturbation is minimal. This technique reveals
important information on alignment of accelerator cells
relative to each other. Experimental results and analysis of
modes of the first dipole band of an X-band accelerator
known as RDDS1 (Rounded Damped Detuned Structure).
Supported by the DOE, grant number DE-AC0376SF00515
[*] R.M. Jones et al, LINAC96, also SLAC-PUB
7287 (1996)
[**] M. Sands and J. Rees, SLAC PEP-95 (1974)
[***] A. Faltens et al., Proc. 8th Int. Conf. HighEnergy Accel., Geneva, p. 338 (1971)
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
219-1493 - Simulations of Wire Measurement of
Wakefields in Accelerating Structures
Nicoleta Baboi (SLAC/ARDB, Menlo Park, California),
Roger Jones (SLAC/ARDA, Menlo Park, California)
The coaxial wire method to measure transverse
wakefield characteristics is a more efficient method
than methods using a beam. The frequency domain
method studies individual modes composing the
wakefields. The method is generally based on
simplified circuit models applicable to particular types
of structures, as for example to short objects or to long
smooth ones, where the impedance is uniformly
distributed. We present an analysis of the wakefield
excited in multi-cell X-band accelerator structures
coupled to a wire. A simulation is made of a full
structure. A direct interpretation of the wakefield and
constituent kick factors is made from a simulation of
the wire measurement. The motivation behind the
modeling is that it will aid the interpretation of wire
measurements of wakefields in multi-cell accelerator
structure coupled to manifolds for the GLC/NLC
(Global Linear Collider/Next Linear Collider).
Supported by the DOE, grant number DE-AC0376SF00515
Type of presentation requested: Poster
Classification: [D04] Instabilities - Processes,
Impedances, Countermeasures
220-241 - Toroidal Cavity Loaded with an Electron
Beam
Edmond David Gazazyan (YerPhI, Yerevan), Davit
Kalantaryan (CANDLE, Yerevan; YSU, Yerevan),
Vitaly Kocharyan (DESY, Hamburg), Taron
Harutyunyan (YSU, Yerevan)
Three problems have been considered in this paper: the
development of Maxwell's equations strict solution
method to define the electromagnetic own values and
own functions of the toroidal cavity; the radiation of
the charged bunch rotating along the average radius,
and, at last, the consideration of the case of a toroid
filled with dielectric medium. The peculiarities of this
radiation have been investigated as well. We suppose
to consider the case when toroid is filled with plasma
like a disperse medium.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
221-322 - Modelling of Accelerating Structures with
Finite-difference Time-domain Method
Eugene V. Pickulin, Victor Malyshev (LETI, SaintPetersburg), Sergey Silaev, Yuri Svistunov (NIIEFA, St.
Petersburg)
A finite-difference time-domain (FDTD) method is very
popular for electromagnetic field modeling. The practical
interest in the method is the ability to calculate fields in time
domain at any time point in the accelerating structure. That
is to say the FDTD method is able to model transient
process taking into account the peculiarity of RF power
input device. A FDTD approach for modeling of alternate
phase focusing structure is presented in this paper. The
modeling of lossy metals is a problem in classical
formulation of FDTD method. This matter is investigated
and one of the solutions is presented in this paper. There are
some problems of signal processing when using timedomain method for resonant structure modeling. The matters
of mode determination are also investigated and presented in
this paper. The simulation results are compared with
experimental data.
D.V. Efremov Scientific Research Institute of
Electrophysical Apparatus
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
222-415 - Instability Thresholds and Generation of the
Electron-cloud in the GLC/NLC and Tesla Damping
Rings
Mauro Torino Francesco Pivi, Tor Raubenheimer
(SLAC/NLC, Menlo Park, California)
In the beam pipe of the Damping Ring (DR) of a linear
collider, an electron cloud may be produced by ionization of
residual gas and secondary emission. This electron cloud
can reach equilibrium after the passage of only a few
bunches. We present recent computer simulation results for
the main features of the electron cloud generation in the
GLC/NLC main DR and for the TESLA DR. Single and
multi-bunch instability thresholds are also calculated for the
NLC main DR. The results are obtained by the computer
simulation codes HEAD-TAIL and POSINST, which were
developed to study the electron cloud effect in particle
accelerators.
Work supported by Department of Energy contract DEAC03-76SF00515
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
223-439 - Comparison of Rate Equation Models for
Equilibrium Beam Parameters
Rainer Hasse, Oliver Boine-Frankenheim (GSI, Darmstadt)
We calculate equilibrium beam parameters from the
counteraction of intrabeam scattering (IBS), electron cooling
(EC) and target interaction for typical beams in the GSI
cooler storge ring ESR and in the proposed HESR. This
work is complementary to kinetic modeling efforts at GSI.
We developed an easy to use simulation tool that includes
various models for the EC rates and the IBS rates, averaged
of the detailed ring lattices. The obtained scaling of the
equilibrium parameters with beam current and energy are
compared with existing experimental data from the
ESR and with kinetic simulation results for the HESR.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
224-465 - Ordered Ion Beam in Storage Rings
Alexander Smirnov, Igor Meshkov, Anatoly Olegovich
Sidorin, Evgeny Syresin, Grigory Troubnikov (JINR,
Dubna, Moscow Region), Takeshi Katayama (CNS,
Saitama), Hiroshi Tsutsui (SHI, Tokyo)
The using of crystalline ion beams can increase of the
luminosity in the collider and in experiments with
targets for investigation of rare radioactive isotopes.
The ordered state of circulating ion beams was
observed experimentally at several storage rings. In
this report a new criteria of the beam orderliness are
derived and verified with BETACOOL code with using
molecular dynamics technique. The sudden reduction
of momentum spread observed on a few rings is
described with this code. The simulation shows a good
agreement with the experimental results. The code has
then been used to calculate characteristics of the
ordered state of ion beams for ion rings which will
have experimental programs for the study of crystalline
beams. A new strategy of the cooling process is
proposed which permits to increase the linear density
of the ordered ion beam.
Work is supported by the RFBR grant #02-02-16911
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
225-473 - MPI Parallel Computation of Wake Fields
by Using Time Domain Boundary Element Method
Kazuhiro Fujita, Hideki Kawaguchi (Muroran Institute
of Technology, Muroran), Thomas Weiland, Igor
Zagorodnov (TEMF, Darmstadt)
This paper presents wake field and wake potential
calculation by using the Time Domain Boundary
Element Method (TDBEM) on the MPI parallel
computation system. The TDBEM is based on the
electric field integral equation (EFIE) and the electric
field integral equation (MFIE) in time domain. In wake
field simulation, an important advantage of these
equations is that electromagnetic fields in an
accelerator cavity are explicitly expressed as a sum of
charged particle self-fields and wake fields in time
domain. On the other hand, the TDBEM has serious
difficulties in practical numerical simulation, such as
numerical instabilities, huge memory requirements, and
heavy calculation cost. However, recent remarkable
progress of computer performance makes the TDBEM
possible to be used in practical simulations. According
to these backgrounds, we apply the TDBEM to wake
field simulation in the MPI parallel computer system.
Simulation results are compared with that of a
conventional method, the Finite Integration Techniques
(FIT), and good agreements are shown.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
226-474 - MATLAB Based TPSA Toolbox for the
Particle Mapping Through Three-dimensional Magnetic
Fields
Ho-Ping Chang, Chin-Cheng Kuo (NSRRC, Hsinchu)
Based on the object-oriented programming of MATLAB, a
truncated power series algebra (TPSA) toolbox has been
developed. The TPSA toolbox as a differential algebra has
been applied to realize the algorithm of particle mapping
through three-dimensional magnetic field configurations.
The capability of symbolic calculation by using this
MATLAB-based TPSA toolbox can be used for the
theoretical simulation and modeling in accelerator physics.
Associated with the use of MATLAB in the control of
machines, one can derive the real machine with a virtual
machine model built in MATLAB. In this paper, the method
of symplectic mapping of three-dimensional magnetic fields
is introduced and the structure of TPSA toolbox is
presented. Applications of TPSA toolbox in the symplectic
mapping of three-dimensional magnetic fields are
demonstrated as well.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
227-536 - Particle-in-cell Based Beam Dynamics
Simulations with the Conformal Finite Integration
Technique and Noise Suppression
Thomas Lau, Erion Gjonaj, Thomas Weiland (TEMF,
Darmstadt)
We describe the application of the Conformal Finite
Integration Technique (CFIT) in the time-domain to beam
dynamics simulations with the Particle-In-Cell (PIC)
method. The conformal method results in a more accurate
field solution for complicated geometries than the traditional
FIT approach. For long-time simulations we investigate
several methods for the suppression of the spurious noise,
typically emerging in PIC simulations. The results are
compared with the analytical solution for a bunch in a semiinfinite waveguide for each of the presented methods. As a
realistic example simulations for the RF-Gun installed at
Photo Injector Test Facility in DESY Zeuthen (PITZ) will
be presented.
T. Lau: Work supported by DESY Hamburg
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
228-548 - Review and Comparison of Simulation Codes
Modeling Electron-Cloud Build Up and Instabilities
Frank Zimmermann, Elena Benedetto, Francesco Ruggiero,
Daniel Schulte (CERN, Geneva), Michael Blaskiewicz,
Lanfa Wang (BNL, Upton, Long Island, New York), Giulia
Bellodi (CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon),
Giovanni Rumolo (GSI, Darmstadt), Kazuhito
Several computer codes written at various laboratories are
employed for
modelling the generation
and the
consequences of an electron cloud. We review the most
popular of these programs, which simulate either the build
of an electron cloud or the instabilities it produces, and we
compare simulation results for identical, or similar, input
parameters obtained from the various codes.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
229-580 - Simulation of Multi-bunch Multi-turn
Instabilities in High Energy Proton Rings:
Algorithms and Results
Alexander Koschik (CERN, Geneva)
A simulation code to study collective effects in multibunch proton machines has been developed and applied
to the CERN SPS and LHC. The 3D simulation
program allows the exploration of long-range effects
due to resistive-wall and HOMs in circular, elliptic and
rectangular vacuum chambers also for uneven filling
schemes. The code has been benchmarked with
measurements in the SPS. Results obtained for LHC,
including beam stability and emittance growth, are
presented and discussed.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
230-643 - Coupling Coefficients in the
Inhomogeneous Cavity Chain
Kateryna Kramarenko, Mykola Ivanovich Ayzatskiy
(NSC/KIPT, Kharkov)
In this paper a mathematical method on the base of a
rigorous electrodynamic approach for description of
inhomogeneous chain of cylindrical cavities is
presented. The form of the obtained for chosen
amplitudes set of equations is similar to the set of
equations that describe the simple coupled circuit
chain. As the cavity have the infinite number of
resonant frequencies, to obtain the coupling
coefficients one have to solve additional infinite set of
linear equations with coefficients that depend on the
frequency. Using the developed method in the case of
inhomogeneous cavity chain we calculated the
dependence of the coupling coefficients on frequency
and geometrical sizes with taking into account the
'long-range' coupling.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
231-645 - Investigation of Numerical Noise in PICCodes
Sascha Schnepp, Stefan Setzer, Thomas Weiland
(TEMF, Darmstadt)
For a detailed analysis of the dynamics of space charge
dominated beams a combination of Particle-in-Cell
methods with efficient FDTD schemes is widely used.
Besides the calculation of the forces acting on the
particles the interaction of the beam itself with the
surrounding geometries is taken into account. A
drawback of this method is its sensitivity to numerical
noise in the spectral range nearby the grid cutoff
frequency. In this paper we will present results of
detailed studies of the impact of the bunch shape on the
level of the numerical noise. Furthermore an a priori
scheme for efficient noise suppression is derived which
does not affect the FDTD update algorithm.
S. Schnepp: Work supported by HGF under contract VHFZ-005;
S. Setzer: Work supported by DFG under contract
GRK410/3
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
232-673 - Reengineering and Refactoring Large-scale
Scientific Programs with the Unified Process: A Case
Study with OSIRIS PIC Program
Jincheol Benjamin Kim (POSTECH, Pohang, Kyungbuk),
Hyyong Suk (KERI, Changwon), In Soo Ko (POSTECH,
Pohang, Kyungbuk; PAL, Pohang)
As science and engineering problems get more complex,
programs which help modelling complicated problems
larger and more sophisticated. This trend makes us
recognize the importance of well-established engineering
disciplines not only in designing large-scale scientific
programs for special purposes in appropriate development
time but also in importing the programs from other research
group and refactor it for conveniences and more advanced
applications. OSIRIS is a large-scale PIC code which was
developed at UCLA for modelling of laser-plasma
interactions. OSIRIS was reengineered and documented in
UML by our group and ported to Linux cluster machine of 8
nodes. We report our current status of developing the
extended version of OSIRIS, which was named as OSIRISX, and how a large-scale scientific programs can be
enhanced efficiently with the Unified Process. Some
guidelines in designing and refactoring large-scale scientific
codes are presented and discussed. A common architecture
model of numerically intensive programs for large-scale
computing is suggested , and it is discussed how we can use
it for rapid development and prototyping of scientific
programs. We also discuss future challenges and prospects
in OSIRIS-X development.
This work was supported by the Korea Research Foundation
Grant(KRF-2003-015-C00121)
J. B. Kim and I. S. Ko also appreciate the financial support
from CHEP at Kyoungpook National University
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
233-727 - Further Results on the Analytic Expression for
the Radial Component of Magnetic Field Produced by a
Finite Length Solenoid
Dan Timus, Scarlat Florin (INFLPR, Bucharest - Magurele)
The magnetic field can be sometimes one of the main
parameters in accelerator design, operation, understanding
or improvement. It influences the beam dynamics in the
generating, forming, accelerating or transporting stages of
the accelerator. As effect to the usefulness of knowledge of
this magnitude, analytical expressions for the radial
magnetic field of the iron-free, finite length solenoid are
given. The radial magnetic field component is presented in
terms of computationally tractable complete elliptic
integrals or related desk computable expressions. Series
expansions are proposed. Recurrence relations and accuracy
of finite series depending on the domain of definition are
commented.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
234-736 - Implementation of Higher Order
Moments for Beam Dynamics Simulation with the
V-Code
Wolfgang Ackermann, Thomas Weiland (TEMF,
Darmstadt)
Based on the moment approach V-Code is
implemented to simulate charged particle beam
dynamics in linear accelerators. Its main aim is to
perform elementary studies in those cases when the
beam can be considered as a whole and thus making
the motion of individual particles negligible in the
overall view. Therefore an ensemble of particles can be
well described by the moments of its phase-space
distribution and the regarded order influences naturally
the achievable accuracy as well as the computational
effort. Since the well known moment equations
generally are not closed, a technique to limit the
number of involved moments has to be applied. So far
all moments up to the second order have been
considered whereas higher order moments are
truncated. As a further step towards higher accuracy
the influence of higher order moments has to be
investigated. For this reason additional third-order
equations are implemented into the V-Code and the
achieved results are compared with previous secondorder-based ones as well as with higher order
approximations.
Work supported by DESY Hamburg
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
235-748 - BCALC - Software for Analysis and
Visualization of the Results of Measured
Isochronous Cyclotrons Magnetic Fields
Ivan Ivanenko, Jozef Franko, Jozef Keniz, Stanislav
Kralik (JINR, Dubna, Moscow Region)
The work is devoted to the development of software
designed to analyze the result of measured isochronous
cyclotrons magnetic fields. Software allows one to
make calculation of basic magnetic field properties and
compare up to six results of analyzed magnetic field.
Obtained results, such as average field, flutter, betatron
frequency, harmonic?s amplitude and phases, are
presented graphically and can be saved as text files for
further processing.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
236-752 - Beam Dynamic Simulation in Spatially
Periodic RFQ Accelerating Structure
Vladimir Pershin, Andrej Kolomiets, Sergey Minaev,
Boris Sharkov (ITEP, Moscow), Stanislav Vinogradov
(MNIRTI, Moscow), Alexander Durkin, Igor Shumakov
(MRTI RAS, Moscow)
A spatially periodic RFQ accelerating structure is
considered for the second stage of the TWAC new
intense injector linac behind of conventional RFQ. The
results of 3D beam dynamic simulation in SP-RFQ are
presented. Special modification of LIDOS code for SP-RFQ
dynamic investigations has been developed. Simulations
validated a possibility to get good performance of the beam
at the SP-RFQ output. LIDOS simulation results
demonstrate good agreement with previous calculation.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
237-878 - Simulation of RF Control of a
Superconducting Linac for Relativistic Particles
Markus Huening (Fermilab, Batavia, Illinois)
We present a code to simulate the rf field and field control
in a superconducting linac for relativistic heavy particles. In
such a linac the field stability is strongly influenced by the
longitudinal beam dynamics. So the code has to simulate
both the field and the beam dynamics with the resulting
varying beam loading. Other effects included in the
simulation are Microphonics and Lorentz force. The code
can simulate both single cavity and vector sum control.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
238-881 - Finding the Circular Magnet Aperture which
Encloses an Arbitrary Number of Midplane-centered
Beam Ellipses
J. Scott Berg (BNL, Upton, Long Island, New York)
In specifying the magnets for an accelerator, one must be
able to determine the aperture required by the beam. In some
machines, in particular FFAGs, there is a significant
variation in the closed orbit and beta functions over the
energy range of the machine. In addition, the closed orbit
and beta functions may vary with the longitudinal position
in the magnet. It is necessary to determine a magnet aperture
which encloses the beam ellipses at all energies and all
positions in the magnet. This paper describes a method of
determining the smallest circular aperture enclosing an
arbitrary number of midplane-centered ellipses.
This research has been supported by the U.S. Department of
Energy under contract no. DE-AC02-98CH10886
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
239-882 - Maps for Fast Electron Cloud Simulations at
RHIC
Ubaldo Iriso, Steve Peggs (BNL, Upton, Long Island, New
York)
Luminosity in several colliders, including RHIC, is limited
by the electron cloud effect. A careful re-distribution of the
bunch pattern around the azimuth of a ring can decrease the
average electron density for a fixed total bunch current,
allowing the luminosity to be increased. In the search for a
bunch pattern that maximizes the luminosity, a fast
computer simulation is a key requirement. We discuss the
use of fast polynomial maps to simulate the bunch to bunch
evolution of the electron density at RHIC. Such maps are
empirically derived from existing conventional slow
simulation codes.
Work supported by U.S. DOE under contract No DEAC02-98CH10886
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
240-973 - The Structure of the High-frequency
Focusing Cells in the Linear Ion Accelerators
Borys Zajtsev, Vasilij Bomko, Olexander Dyachenko,
Anatolij Kobets, Zinaida Ptukhina, Sergej Tishkin
(NSC/KIPT, Kharkov)
The results development version of the high-frequency
quadrupole doublet (RFQD) are presented. Due to
simple design solutions, the RFQD provides radial and
phase stability of high-current ion beams having high
acceleration rate. The RF focusing doublet consists of
two cells 3/2 ?? in length each and includes two
quadrupoles having the opposite direction of the
electric field applied between ?fingers?. Each cell
includes 3 gaps; two of them are axial symmetric and
are located in accelerating half-periods of the RF field.
In the gap with the negative field, the fingers are
located which form a quadrupole along the whole
length ??/2. The distance between fingers and between
finger ends and drift tubes is defined by the aperture
value. Two spacings between the fingers and drift tubes
are also accelerating gaps in each plane of the fingers.
To form such an RFQD accelerating and focusing
structure between drift tubes to which a potential is
applied, two tubes holding quadrupole electrodes are
added. Such a doublet is placed in the sequence of
accelerating cells of the traditional type in different
structures such as interdigital structures being used for
acceleration of heavy ions, and structures for
accelerating high-current proton beams
such as
CCDTL, spoke-cavity, re-entrant-cavity and others.
That spares the bulk magnetic quadrupoles presenting
technologic difficulties.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
241-974 - Numerical Calculation of Fields in the
Structures with High-frequency Quadrupole
Focusing with the Method of Auxiliary Charge
Vasilij Bomko, Zinaida Ptukhina, Sergej Tishkin, Borys
Zajtsev (NSC/KIPT, Kharkov)
A variant of the integral equation method, the method
of auxiliary charges, is used for calculating quasielectrostatic fields in an RF quadrupole. According to
the method, a potential of the electrostatic field is
presented as a superposition of point charge fields, the
point charges being located outside a region studied at
a certain distance from the region. Magnitudes of
charges N was determined from the boundary
conditions in N points.Specifying the point charges is
equivalent to use of a certain charge density on
electrode surfaces. The given algorithm is realized in
the QFLD code.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
242-975 - Dynamics of High-current Ion Beams in the
Accelerator Combining APF and RFQD
Vasilij Bomko, Zinaida Ptukhina, Sergej Tishkin
(NSC/KIPT, Kharkov)
The results of investigations of the high-current bean
dynamics are presented. Acceleration rate and radial and
phase stability are provided by combination of RF focusing
of two types alternating phase focusing (APF) and focusing
with the RF quadrupole doublets (RFQD). This structure of
the accelerating and focusing channel, from one hand,
allows us to increase the limiting current of the beams being
accelerated, and from other hand to achieve a high
acceleration rate. The investigation of the beam dynamics at
different stage of acceleration was performed for the
focusing period where the synchronous phase changes from
a region of negative values to a region of positive phases
which are small in absolute value. With that, the main
focusing effect is by way of RFQD. The optimization of the
accelerating and focusing channel with the sequence of cells
having &#1040;/q=4 with APF and RFQD in the energy
region of 30-100 keV/n has been performed. The efficiency
of the RFQD for accelerating high-current proton beams is
also investigated.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
243-978 - Particle-in-cell Numerical Simulation of the
Particle Dynamics in ECR Source
Grigori Shirkov (JINR, Dubna, Moscow Region), Vladimir
Alexandrov, Vladimir Shevtsov (JINR/PPL, Dubna, Moscow
Region)
A summary of recent development of physical and
mathematical basements and the first version of computer
code library based on the particle-in-cell method are
presented. The code library is aimed for the threedimensional (3D) simulation of the ECR plasma and ion
production in the ECR ion source. The particle-in-cell (finite
particle) method is one of the most powerful methods for the
numerical simulation of multicomponent ECR plasma and
electron-ion beams. This method allows studying the
detailed characteristics of plasma, taking into account the
distribution functions of particles (spatial, velocity and
energy distributions), real self and external fields, particleparticle interactions and many other effects. This technique
promises to provide very precise numerical simulations and
optimizations of ECR ion sources. The first results of
simulations of ECR source plasma are presented. It has been
shown that a complete and adequate description of ECR
plasma requires the full-scale 3D model and computer
codes. This is out of frames of existed project and could be
an aim of some addition investigations.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
244-1023 - Simulation Technique for Study of Transient
Self-consistent Beam Dynamics in RF Linacs
Viktor Mytrochenko, Anatoliy Opanasenko (NSC/KIPT,
Kharkov)
The report describes a simulation technique for study of
unsteady self-consistent dynamics of charged particles in
resonant linacs. The technique allows simulating the linacs
that consist of resonant cavities and traveling wave
sections. The proposed approach is based on unsteady
theories of excitation of resonant cavities and
waveguides by a beam of charged particles and RF
feeders. The theory of waveguide excitation is
generalized to the case of spatially inhomogeneous
traveling wave structures. The system of self-consistent
differential equations for fields and motion of particles
is integrated over time and space. The SUPERFISH
code is used to evaluate characteristics of the axially
symmetrical cavities and traveling wave sections. The
PARMELA code is applied to simulate motion of the
particles at each time step of the integration. In such a
way the fields and beam characteristics in the axially
symmetrical accelerating structures can be obtained for
transient and steady state operation. Description of the
algorithm and results of its validation are presented.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
245-1092 - Upgraded Symplectic 3D Beam Tracking
of the J-PARC 3 GeV RCS
Masashi Shirakata, Hiroshi Fujimori, Yoshiro Irie
(KEK, Ibaraki)
The J-PARC 3 GeV ring is a rapid cycling synchrotron
which consists of the large bore size magnets. The
beam tracking with the 3D distributed magnetic fields
is kept developing in order to investigate the beam
injection process. In the case of the high intensity
hadron accelerator, an accurate beam simulation is
important for the designing because a very small
amount of beam loss can be critical from the
maintenance point of view. In order to improve the
tracking accuracy and to save the calculation time, the
symplectic integration with the fractal decomposition
method has been introduced. The updated simulation
results of the beam injection on the J-PARC 3 GeV
RCS and the improved performance of `GenericSolver'
are presented in this paper. The quadrupole fields are
also treated as the 3D distributed magnetic fields
because they interfered with the bump magnet fields.
The remarkable features on the large bore magnet
system in the ring accelerator are also discussed.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
246-1101 - Simulation Study of the Beam Loading
Effect in an RF Gun
Katsuhiro Shinto, Hiroyuki Hama, Fujio Hinode,
Atsushi Miyamoto, Takumi Tanaka (LNS, Sendai)
Because of simple structure and apparatus, a
thermionic rf gun has been considered to be employed
in a new pre-injector for the future synchrotron
radiation facility at Tohoku University. A 3-D beam
simulation code for the rf gun using a Finite Difference
Time Domain (FDTD) method to solve Maxwell's
equations has been developed. In the rf gun, especially
in case of the high beam current, electromagnetic fields
induced by the electron beam are considered to affect
beam characteristics such as beam emittance and
energy spread. In the FDTD method, because the
Maxwell?s equations are able to be solved including the
term of current density of the charge, the electromagnetic
fields produced by both the external rf power and the
electron beam can be anticipated. Using the simulation code,
beam loading effects on the characteristics of the electron
beam extracted from the rf gun is investigated.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
247-1198 - Parallel Particle in Cell Computations with
GdfidL
Warner Bruns (WBFB, Berlin)
The electromagnetic field solver GdfidL has been extended
to compute with free moving charges. For computing in
parallel, GdfidL partitions the computational volume in
many small subvolumes. Each processor computes the
electromagnetic field in its part of the whole volume. In
addition to the normal field update equations, the movement
of the particles must be computed from the Lorentz-force,
and the convection current due to the moving charges must
be computed and be used to change the electric field near
the particle. For each particle, these computations are
performed by the processor which is responsible for the
volume where the particle is in. Details of the parallel
implementation of the used algorithm, Particle in Cell, are
given.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
248-1209 - Calculation of Electron Beam Dynamics of
Accelerator Lue-200
Vladimir Aleksandrov, Vladimir Shevtsov (JINR/PPL,
Dubna, Moscow Region), Nikolay Kazarinov, Mikhail
Sazonov, Anatoly Sumbaev (JINR, Dubna, Moscow Region)
The results of calculation of focusing and transportation
systems of an electron beam of accelerator LUE-200 - the
driver of a pulse source of resonant neutrons (IREN) JINR
(Dubna) are presented. Calculations of the beam dynamics
in the traweling wave accelerator were carried out with the
help of PARMELA code for a designed configuration:
elements of accelerating system, system of magnetic
focusing of the accelerator from an electron source up to the
end of accelerating structure, the channel of transportation
of the beam from an output of accelerating structure up to a
target. Modelling modes of acceleration and transportation
for various parameters of the focusing magnetic field in the
accelerator and the channel, various currents of the beam
and various initial distributions of electrons is lead.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
249-1210 - Electron Beam Dynamics Simulations for the
Low Emittance Gun
Micha Dehler, Simon Leemann (PSI, Villigen), Arno Candel
(ETH, Zürich)
We report on theoretical simulation performed for the
development of a high brightness, field emitter based
electron gun suitable for an Angstrom wavelength free
electron laser\cite{LEG}. First simulations have been done
with available codes in 2 1/2D and 3D for basic gun
configurations showing the global and local (due to the
granularity of the emitter array) effects on the
emittance dilution.Design and construction started on a
test setup consisting of a 100 keV electron gun with
solenoidal focusing and a diagnostics module. In
addition to solenoid focussing, anode shaping will be
investigated in order to compensate for non-linear
fields leading to space charge blow-up. For advanced
simulations of field emitter based guns allowing to
resolve individual emitters and to capture the influence
of mechanical imperfections, a massive parallel code
for 3D particle-in-cell simulations is in development.
The electromagnetic field solver is fully functional and
the particle tracker has been completed in its basic
structures.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
250-1233 - Modeling of Beam-loading Effect
Vladimir Shevtsov, Vladimir Aleksandrov (JINR/PPL,
Dubna, Moscow Region), Nikolay Kazarinov, Mikhail
Sazonov, Anatoly Sumbaev (JINR, Dubna, Moscow
Region)
Analytical estimations and results of numerical
simulation of beam-loading effect in accelerating
sections of LUE-200 are done. Results of simulation of
electron beam dynamics in linac and transportation line
are presented.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
251-1241 - A more Accurate Approach to
Calculating Proton Bunch Evolution under
Influence of Intra-beam Scattering in a Storage
Ring.
Ilia Agapov, Ferdinand J Willeke (DESY, Hamburg)
Some perturbations of discrete nature are known to
influence the performance of a proton storage ring,
contributing to parasitic background, decay of beam
currents and bunch tail buildup. Such are, for example,
intra-beam scattering and residual gas scattering .These
processes are to a big extent described by existing
analytical theory. The latter, employing a large amount
of averaging, usually neglects effects arising from
system nonlinearity. So, the motion of tail particles in
the presence of a sufficiently nonlinear RF voltage
under influence of intra-beam scattering strongly
deviates from the average across the bunch and the
analytical approach seems inadequate for it. To
overcome this situation we have developed more
accurate numerical methods for calculations of bunch
evolution under influence of a rather broad class of
jump-like perturbations. Here we present the
computational algorithms and their application to
assessment of coasting beam and proton background in
HERA-p.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
252-1270 - A ROOT Interface to the Unified Accelerator
Libraries
Raymond Patrick Fliller III, Nikolay Malitsky (BNL, Upton,
Long Island, New York)
The Unified Accelerator Libraries software is an open
source accelerator simulation environment providing
support for associations between diverse accelerator
algorithms and accelerator components.
Accelerator
algorithms are implemented using C++, connected by
Common Accelerator Objects (such as Element, Bunch,
Twiss, etc.). A PERL interface is provided to simplify the
use and integration of each library in simulations.The ROOT
Object Oriented Data Analysis Framework is a set of C++
classes surrounding a C++ interpreter named CINT. These
classes provide various data analysis, visualization,
programming, and I/O functions useful for the analysis of
simulations and data. A ROOT interface to the UAL
provides the advantages of including analysis of the
simulation in the same program as the simulation code and
easier access to the UAL codes. This paper dicusses the
implementation of a ROOT interface to the UAL. We also
discuss a set of classes based on ROOT that are useful for
the analysis of accelerator simulations and data.
Work performed under the auspices of the U.S. Department
of Energy
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
253-1290 - MADX-UAL Suite for Off-line Accelerator
Design and Simulation
Nikolay Malitsky, Raymond Patrick Fliller III, Fulvia
Caterina Pilat, Vadim Ptitsyn, Steven Tepikian, Jie Wei
(BNL, Upton, Long Island, New York), Frank Schmidt
(CERN, Geneva), Richard Michael Talman (LEPP, Ithaca,
New York)
We present here an accelerator modeling suite that
integrates the capability of MADX and UAL packages,
based on the Standard eXchange Format (SXF) interface.
The resulting environment introduces a one-stop collection
of accelerator applications ranging from the lattice design to
complex beam dynamics studies. The extended capabilities
of the MADX-UAL integrated approach have been tested
and effectively used in two accelerator projects: RHIC,
where direct comparison of operational and simulated data
is possible, and the SNS Accumulator Ring, still in its
design phase.
Work supported by the SNS through UT-Battelle, LLC,
under contract DE-AC05-00OR22725 for the U.S.
Department of Energy
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
254-1305 - Coupled S-Parameter Calculation for the
Computation of RF Properties of Complex Structures
Karsten Rothemund, Hans-Walter Glock, Dirk Hecht,
Ursula Van Rienen (Rostock University, Rostock)
RF properties like eigenfrequencies and eigenmodes of
accelerator components are usually computed by numerical
field solving codes. In case of complex structures where full
3D modelling is required the numerical effort often exceeds
the available capabilities of modern computer hardware. For
these cases a method called "Coupled S-Parameter
Calculation (CSC)" has been developed. This method
is based on the scattering parameter description of the
components of a complex structure found with field
solving codes or analytically for components of special
symmetry. Once calculated the S-parameters of a
component may be reapplied if the component
repeatedly occurs in the complex structure. The paper
presents the formalism of the CSC method and its
application for the calculation of eigenfrequencies and
Q-values of modes in the 3rd harmonic section of the
TTF FEL facility.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
255-1343 - A Fast C++ Library for the Evaluation
of Truncated Taylor Series Using Metaprogramming Methods
Andreas C. Kabel (SLAC/AC, Menlo Park, California)
The fast evaluation of multivariate polynomials plays
an important role in particle tracking studies for
circular accelerators, as the one-turn map of the ring or
the transport maps between elements can be
represented as a truncated Taylor series of relatively
high order in the phase-space variables. Tracking
studies can require 10^11 or more evaluations of such a
map, so clearly, fast algorithms are required. We
present a novel approach using meta-programming
techniques available in the C++ language. Also, our
code utilizes parallel floating-point instructions
available on modern workstation processors. The
performance of our code rivals or exceeds that of
assembly-language codes hand-coded for a particular
dimension and truncation degree, surpassing
conventional algorithms coded in high-level languages
such as Fortran or C by factors of 2...8 in speed. We
provide benchmarking results and describe the
interface of our library to C++, Fortran, and C codes.
Work supported by Department of Energy contract DEAC03-76SF00515
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
256-1375 - Development of a 3D-Gun-Code based
on a Charge Conserving Algorithm
Erion Gjonaj, Thomas Weiland (TEMF, Darmstadt)
Recent efforts in the development of electron sources
are aiming at high intensity electron beams, beyond the
limitations posed by space-charge effects in
conventional guns. Field emitter arrays, multi-beam
and sheet-beam guns are a few examples of emerging
technology, which require an accurate characterization
of the limiting current in complicated 3D-geometry.
The newly developed gun code at the Technische
Universität Darmstadt, implements a novel approach to
the numerical simulation of space-charge-limited
electron emission, which is based on the local
conservation of charge for arbitrary cathode surfaces. It
is shown that, imposing exact charge conservation
using the CAD-data of the geometry eliminates the
spurious oscillations in the charge density, which
typically arise when the piecewise-planar diode
approximation is applied in the simulation. The accuracy of
this approach is demonstrated in the validation study of a
spherical diode and in the large-scale simulation of a
Traveling Wave Tube amplifier.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
257-1388 - Emittance Diluition due to 3D Perturbations
in RF Photoinjectors.
Marcello Quattromini, Luca Giannessi, Concetta Ronsivalle
(ENEA C.R. Frascati, Frascati (Roma))
The predictions from different simulation codes are
compared to investigate the effects of non axis-symmetric
conditions, fluctuations in cathode's quantum efficiency and
other sources of dishomogeneities in the performances of a
typical RF photoinjector. The layout includes a RF gun and
a focusing solenoid in a configuration aimed at minimizing
the emittance growth due to space charge effects.
Ente per le Nuove Tecnologie, l'Energie e l'Ambiente
(ENEA, Sede di Frascati)
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
258-1419 - Comparison of Lattice Tools with Analytic
Formulae for Orbit Functions of a Nonscaling FFAG
Accelerator
Shane Rupert Koscielniak, Dobrin Kaltchev (TRIUMF,
Vancouver), Carol Johnstone (Fermilab, Batavia, Illinois),
Albert A. Garren (LBNL/CBP, Berkeley, California)
Fixed Field Alternating Gradient (FFAG) magnetic lattices
with fixed, possibly high, radio-frequency proposed for
muon acceleration have unusual requirements: relative
momentum swing dp/p of +/- 30% and relative spread of
revolution frequencies < 10^(-3). It is not evident whether
the existing accelerator optical design codes are sufficiently
accurate for such a large momentum range. Analytic
expressions for orbit displacements, tunes and path length
have been derived for thick-element models of doublet,
F0D0 and FDF triplet lattices; it is this paper's purpose to
compare these with values computed by SYNCH and
COSY, and truncated Taylor maps constructed by Lie
algebra. The mutual agreement of results from independent
sources will serve to validate them all. A mathematical
necessity is that one at least of the magnets be of the
combined-function type, and with entrance and exit faces
disposed in a sector layout. It is sufficient to consider the
triplet case because in the limit that the two F quadrupoles
are combined, the cell reduces to the simpler F0D0. We use
as our example a "nonscaling" FFAG ring proposed for
accelerations of muons over the momentum range 10-20
GeV/c.
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
259-1442 - Simulation and Comparison with Beam
Tests of the Digital Bunch-by-bunch Transverse
Damper in the Fermilab Main Injector
Dennis Nicklaus, G. William Foster, Vladimir
Kashikhin (Fermilab, Batavia, Illinois)
The resistive wall instability of the Fermilab Main
Injector accelerator has been simulated using rigid
bunch approximations of a beam signal.
This
simulation
is
compared
with
experimental
measurements acquired with a digital data acquisition
system. Further simulation models the behaviour of
the Main Injector transverse damper system.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
260-1502 - New Discretization Scheme for Wake
Field Computation in Cylindrically Symmetric
Structures
Robert Hampel, Thomas Weiland, Igor Zagorodnov
(TEMF, Darmstadt)
Collective effects due to wake fields are a limiting
factor in almost every new front line accelerator. Since
the early 80's computer codes such as TBCI and
MAFIA have been developed for computing wake
fields in realistic accelerator structures. With the advent
of linear collider studies and small wavelength FEL
projects these codes had to face a severe limitation. For
the very short bunches in these new accelerators
combined with the need for an analysis of very long
sections the discrete dispersion became a serious
drawback. This effect of having only discrete field
values rather than continous ones can be overcome by
special algorithms such as semi-implicit integrators as
used e.g. in the wake field code ECHO. In this paper
we present a new explicit approach which combines
the advantage of explicit algorithms (fast) with the
absence of dispersion in beam direction.
Type of presentation requested: Poster
Classification: [D05] Code Developments and
Simulation Techniques
261-1505 - Progress in 3D Space-charge
Calculations in the GPT Code
Gisela P&#246;plau, Ursula Van Rienen (Rostock
University, Rostock), Marieke de Loos (PP, Soest), Bas
van der Geer (TUE, Eindhoven)
The mesh-based 3D space-charge routine in the GPT
(General Particle Tracer, Pulsar Physics) code scales
linearly with the number of particles in terms of CPU
time and allows a million particles to be tracked on a
normal PC. The crucial ingredient of the routine is a
non-equidistant multi-grid Poisson solver to calculate
the electrostatic potential in the rest frame of the bunch.
The solver has been optimized for very high and very
low aspect ratio bunches present in state-of-the-art
high-brightness electron accelerators. In this paper, we
explore the efficiency and accuracy of the calculations
as function of meshing strategy and boundary
conditions.
supported by DESY, Hamburg
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
262-1527 - End to end simulations of the RX2 beam
transport
Nicolas Pichoff, Jean-Michel Lagniel (CEA/DAM, Bruyèresle-Châtel)
RX2 is a project aiming to produce a high flux of X-rays for
radiography purpose. We proposed an RF linac using a DC
photo-injector producing 20 bunches with 100nC each at
352 MHz. The beam is then injected in 4 RF
superconducting cavities and accelerated to 40 MeV. It is
then focused on a target producing X-rays. Here is presented
the design, the specificities, and the beam simulations from
the cathode to the target by coupling 2 multiparticle codes :
PARMELA and PARTRAN.
CEA/DIF/DPTA/SP2A-France
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques
263-1528 - End to End Multiparticle Simulations of the
AIRIX Linac
Nicolas Pichoff (CEA/DAM, Bruyères-le-Châtel)
AIRIX is a working 3 kA, 20 MeV induction accelerator. It
has been designed with an enveloppe code : ENV. A new set
of multiparticle codes (PBGUNS, MAGIC, PARMELA and
PARTRAN) has been used recently to simulate the beam
transport with an higher accuracy especially taking into
account the field non-linearities. A dedicated space-charge
routine has been written. The calculation results have been
compared to experimental measurements.
CEA-DIF/DPTA/SP2A-France
Type of presentation requested: Poster
Classification: [D05] Code Developments and Simulation
Techniques