Session 7:
Accelerator Technology,
SPC Coordinator: J-M. Lagniel CEA, Paris and C. Pagani, INFN-LASA, Milan
1-123 - Control of the Small Isochronous ring
Jose Alberto Rodriguez, Felix Marti (NSCL, East
Lansing, Michigan), Eduard Pozdeyev (Jefferson Lab,
Newport News, Virginia)
The purpose of this paper is to describe the control
system of the Small Isochronous Ring (SIR) developed
and built at the National Superconducting Cyclotron
Laboratory (NSCL) at Michigan State University
(MSU). SIR is a small-scale experiment that simulates
the dynamics of intense beams in large accelerators. A
20 to 30 keV hydrogen or deuterium ion bunch is
injected in the ring, extracted after a variable number of
turns and its longitudinal profile is studied.
Information about the electronics used and software
written to control different injection line, ring and
extraction line elements is included. Some of these
elements are magnets, electrostatic quadrupoles,
electric and magnetic correctors, scanning wires,
emittance measurement system, chopper and a fast
Faraday cup.
Work supported by NSF Grant # PHY-0110253
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
2-814 - All Digital IQ Servo-system for CERN
Linacs
Anton Rohlev, Johannes Broere, Roland Garoby,
Serrano Javier, Ioan Kozsar (CERN, Geneva)
A VME based control system has been developed and
built at CERN for the servo loops regulating the field
in linac accelerating structures. It is an all-digital
system built on a single VME card, providing digital
detection, processing, and modulation. It is foreseen to
be used, in different versions, for the needs of both
present and future CERN hadron linacs. The first
application will be in the energy ramping RF chain of
the CERN Heavy Ion Linac (linac 3). In addition to
regulating the cavity field, the system incorporates the
measurement and control of the cavity resonance as
well as an imbedded loop stabilizing the gain and the
phase of the final amplifier operating near saturation.
The design principle and the experimental results are
described.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
3-818 - Upgrading the Control System at KCSR.
Iouri Krylov, Vladimir Korchuganov, Lidiya Moseiko,
Nikolai Moseiko, Vadim Novikov, Alexandre
Valentinov, Yury Yupinov (RRC Kurchatov Institute,
Moscow)
Till now Kurchatov Centre of Synchrotron Radiation
facility control system is based on a CAMAC-oriented
computers network. In this paper the project of
upgrading and results of prototyping of the new equipment
is submitted. Upgrading includes two levels. First, it is
possible to create the modern CAMAC crate-controller,
connected with standard network. More advanced variant
will consist in replacement of CAMAC modules with the
embedded controllers of equipment. Second level is a
creation of a local managing network of personal computers,
as consoles of the control system. The control system is
functionally divided into four levels: 1) the controllers
managing in a real-time mode by the executive equipment;
2) the workstations which are supporting the link with
controllers by CAN-network; 3) the server of applications
containing a dynamic database; 4) the PCs network for users
applications. Examples of realisation of the software are
presented.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring Control
Systems
4-895 - Low Cost Magnetic Field Controller
Marcos Martins, Mauricio Lima Lopes, Alexandre Almeida
Malafronte (USP/LAL, Bairro Butantan), Jiro Takahashi
(IFUSP, Sao Paulo)
The Instituto de Física da Universidade de São Paulo
(IFUSP) is building a two-stage 31 MeV continuous wave
(cw) racetrack microtron. This machine has several dipole
magnets, like the first and second stage recirculators, and
other smaller ones in the transport line. These magnets must
produce very stable magnetic fields to allow the beam to
recirculate along very precise orbits and paths. Besides, the
fields must be reproducible with great accuracy to allow an
easier setup of the machine, though the effects of hysteresis
tend to jeopardize the reproducibility. If the magnets are set
up by setting the current of the power supply, temperature
effects over the magnets and power supply tend to change
the field. This work describes an inexpensive magnetic field
controller that allows a direct measure of the field through a
Hall probe. It includes a microcontroller running a feedback
algorithm to control the power supply, to keep the field
stable and reproducible. The controller can also execute
algorithms to ramp up and down the power supply always in
the same way, to minimize hysteresis.
FAPESP, CNPq, USP
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring Control
Systems
5-950 - SPEAR 3 Commissioning Software
Jeff Corbett, Greg Portmann, James A. Safranek, Andrei
Terebilo (SLAC/SSRL, Menlo Park, California)
In order to meet the tight SPEAR 3 accelerator
commissioning schedule, a software package was assembled
to streamline experimental measurements and data analysis.
At the heart of the software is a MATLAB "middle layer"
with an element definition database and channel access link
for fast and easy communication with the EPICS control
system. Originally adapted from work at the ALS, the
middle layer allows direct control from the MATLAB
command line, use in the form of short "scripts" for
specific experiments and integration into high-level
application programs. The revised software is also
machine-independent. This paper outlines the software
architecture and provide examples with results from the
SPEAR 3 accelerator commissioning effort.
Work supported in part by Department of Energy
Contract DE-AC03-76SF00515 and Office of Basic
Energy Sciences, Division of Chemical Sciences
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
6-1188 - Upgrading the LNLS Control System from
a Proprietary to a Commercial Communications
Environment
José Guilherme Ribas Sophia Franco, Rafael
Mortensen Ernits, Michele de Carvalho Fernandes,
Ana Flávia Aparecida Gouveia, James R. Piton,
Marco Antonio Raulik, Felipe Daniel Schiavon
Rodrigues (LNLS, Campinas)
The LNLS Control System was built over a proprietary
technology, due to governmental policy of information
technology in the mid 80's. This made interfacing to
commercial systems difficult, limited the technology
transfer to the private sector, required a staff with
specific knowledge and reduced the possibility of new
implementations on the system. Nowadays, the cost to
move all of our hardware to a commercial one is out of
our budget. This paper describes a proposal, the
viability study and first results to move only the
communication
interfaces
to
a
commercial
environment, keeping most of our hardware unchanged
and opening the way to gradually move the system to
widely accepted standards, when and if necessary. This
solution allows a smooth implementation without long
periods of machine shutdown and keeps the possibility
to operate the machine concurrently between old and
new communication interfaces.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
7-1202 - Reconfigurable Hardware Resources in
Accelerator Control Systems
Dario Giove, Carlo De Martinis, Marco Mauri
(INFN/LASA, Segrate (MI))
The development of modern accelerator control
systems has taken advantage of the possibility to use
standard architecture designs based on the experience
gained in industrial applications. Communication
buses, board formats, operating systems, network
protocols and operator interface software are the main
elements of this new approach. In this paper we will
discuss the way to apply this method also to the design
of electronic boards which call for custom design of
particular circuits and capabilities. The use of FPGA
based standard modules along with the possibility to
customize them using a standard LabVIEW
environment to obtain reconfigurable hardware
resources will be presented.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring Control
Systems
8-1422 - Study of Arc-related RF Faults in the CEBAF
Cryomodules
Edward Daly, Douglas Curry, John Musson, Ganapati
Myneni, Tom Powers, Timothy Whitlatch (Jefferson Lab,
Newport News, Virginia)
A series of measurements has been conducted on two
superconducting radio-frequency cavity pairs, installed in
cryomodules and routinely operated in the Continuous
Electron Beam Accelerator Facility, in order to study the
RF-vacuum interaction during an RF fault. These arcrelated fault rates increase with increasing machine energy,
contribute to system downtime and directly affect the
accelerator?s availability. For this study, the fundamental
power coupler waveguides have been instrumented with
vacuum gauges, additional arc detectors, additional infrared
sensors and temperature sensors in order to measure the
system response during both steady-state operations and RF
fault conditions. Residual gas analyzers have been installed
on the waveguide vacuum manifolds to monitor the gas
species present during cooldown, RF processing and
operation. Simultaneous measurements of the signals are
presented, a comparison with analysis is shown and results
are discussed. The goal of this study is to characterize the
RF-vacuum interaction during normal operations. With a
better understanding of the installed system response,
methods for reducing the fault rate may be devised,
ultimately leading to improvements in availability.
Work supported by the U.S. Department of Energy under
contract DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring Control
Systems
9-1504 - EPICS Based Control System for the KOMAC
RF System
Jong Chel Yoon (PAL, Pohang)
This paper presents the RF control system for Korea Multipurpose Accelerator Complex (KOMAC). KAERI (Korea
Atomic Energy Research Institute) has been performing the
project named KOMAC. As the 3nd phase of the project,
20MeV proton accelerating structure is under development.
The new design is based on the use of VME based Multifunction modules connected to the specific low level RF
Controllers(LLRF) via distributed I/O modules and Serial
communication modules. The control system was based on
EPICS (Experimental Physics and Industrial Control
System) from the end of 2003. Installation and
commissioning of the RF module is scheduled on 2004.
Control system to integrated the RF System to the KOMAC
control system is implemented. Hardware, software and
various applications are developed to support the operation
of RF Control system. This paper EPICS based control
system for KOMAC RF
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring Control
Systems
10-1543 - Test Results of Superconducting Cavities
Produced and Prepared Completely in Industry
Michael Pekeler, Stefan Bauer, Bernd Griep,
Hanspeter Vogel, Peter vom Stein (ACCEL, Bergisch
Gladbach)
Superconducting cavities for a variety of recent
projects are produced and prepared for operation in
industry. We report on test results of those cavities
produced and prepared at ACCEL. The preparation of
the cavities includes chemical treatment (BCP), rinsing
with high pressure water and assembly in a clean room.
The following cavity types were treated: 400 MHz
single cell cavities for LHC, 500 MHz single cell
cavities of the Cornell CESR design for our
superconducting accelerating modules, 1300 MHz
TESLA type cavities, 176 MHz and 160 MHz
halfwave resonators and a 352 MHz CH-mode cavity
for ion accelaration.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
11-1545 - Production of Superconducting
Accelerator Modules for High Current Electron
Storage Rings
Michael Pekeler, Stefan Bauer, Bernd Griep,
Hanspeter Vogel, Peter vom Stein (ACCEL, Bergisch
Gladbach)
For Diamond Light Source, ACCEL was awarded to
produce three more superconducting 500 MHz
accelerator modules of the Cornell CESR design. With
the already 6 modules produced for Cornell, NSRRC
and CLS, this module can now be considered as a kind
of standard product. In this paper we describe the basic
parameters and guaranteed values of this module and
will also report on the performance of delivered
modules.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
12-1784 - New RF Measuring System for Cavity
Characterization
Sergey Stark, Giovanni Bisoffi, Vincenzo Palmieri,
Anna Maria Porcellato (INFN/LNL, Legnaro, Padova)
New computer based mobile measuring system for
laboratory
and
online
characterization
of
superconducting cavities has been put into operation at
LNL. The system covers the frequency range from 80
to 350 MHz and represents a reliable, fast and precise
instrument for cavity testing. The list of automatic and
semiautomatic procedures includes line calibrations,
frequency sweep, decay time measurement, Q(Eacc)
curve acquisition and pulse conditioning.
Type of presentation requested: Poster
Classification: [T04] Accelerator/Storage Ring
Control Systems
13-42 - First Tests of a High Power HOM-Damped
500MHz Cavity
Frank Marhauser, Ernst Weihreter (BESSY GmbH, Berlin)
A prototype high power 500 MHz copper cavity with three
tapered circular waveguides for broadband higher order
mode (HOM) damping has been fabricated especially for the
use in 3rd generation synchrotron radiation sources. Low
power impedance measurements are presented and
compared with theoretical simulations to verify the expected
HOM damping efficiency as well as the fundamental mode
shunt impedance. After a careful cleaning and baking
process to reduce the vacuum pressure the cavity has been
conditioned at high power. All relevant parameters of the
cavity are reported.
Work funded by the EC under contract no. HPRI-CT-199950011 and supported by BMBF, by the Land Berlin and by
DAAD/Germany
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
14-162 - Non-resonant Accelerating System at the KEKPS Booster
Shigeshi Ninomiya (KEK, Ibaraki)
The non-resonant accelerating system for the KEK-PS
booster accelerator has been constructed. The system has
been operating since October 2003 without trouble. The
accelerating gap in the system is loaded with magnetic cores
of high permeability. The cores produce high resistive
impedance at the gap. The power dissipated in the cores
amounts to 50kW at 16kV accelerating voltage. It is
removed by forced-air cooling system. At the last operation
of the accelerator, with the help of new COD-correction
system, the average beam intensity of the booster increased
to 2.6E+12ppp, which is 30% higher than before.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
15-371 - Triggers for RF Breakdown
Jim Norem, Zeke Insepov (ANL, Argonne, Illinois)
We outline a model of breakdown in rf cavities. Breakdown
can be triggered by two mechanisms, one is fracture of the
surface due to the tensile stress produced by the electric
field, the second is Ohmic heating at grain boundaries and
defects at very high current densities. We show how this
model follows from measurements of local electric fields
using electron field emission, and show how the model
applies to the operating conditions of a variety of rf
structures. This model may have some relevance to SCRF
and DC structures.
USDOE/HEP
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
16-382 - Multi-harmonic RF Accelerating System for
Medical Proton Synchrotron
Kazuyoshi Saito, Mamoru Katane, Kaoru Kobayashi, Koji
Masui, Kunio Moriyama, Hideaki Nishiuchi, Hiroaki
Sakurabata, Hirohisa Satomi (Hitachi, Ltd., Ibaraki-ken)
We have developed an RF accelerating system for medical
proton synchrotron. The RF cavity is a tuning-free wideband
type, loaded with FINEMET cores, which is driven by a
solid-state RF power amplifier with operation frequency
range between 1MHz and 10MHz. Multi-harmonic RF
acceleration scheme has been realized with the RF
control system, to reduce beam loss by space-charge
effect in low energy region. The original techniques for
high-speed digital signal processing and high-precision
RF signal processing have been applied, in order to
fulfill feedback control of the frequency, phase and
amplitude of the second and third harmonic RF signals
as well as the fundamental one.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
17-407 - A HOM Damped Planar Accelerating
Structure
Alexei Blednykh, Heino Henke (TET, Berlin)
The problem of very fast higher order mode (HOM)
suppression, in the order of 1ns, was investigated for a
planar 30GHz accelerating structure. Both, damping
and detuning were considered. A sufficient suppression
could be achieved by damping waveguides in every
cell in vertical and in horizontal direction. Finally, a
scaled-up 10GHz model was built. It is a 35 cm long
aluminum structure, which was machined by highprecision milling. In order to reduce the surface
gradient on the input/output coupling irises a
symmetrical RF coupler was developed. The HOM
damping is accomplished by coupling six damping
waveguides to each accelerating cell. The waveguides
are loaded by a low resitivity RF load. The whole
structure with waveguides and loads was optimized by
means of the computer code GdfidL. The paper gives
the design criteria and the results of s-parameter and
bead-pull measurements.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
18-457 - New Waveguide-type HOM Dampers for
the ALS Storage Ring RF Cavities.
Slawomir Kwiatkowski, James Julian (LBNL/ALS,
Berkeley, California), Kenneth Michael Baptiste
(LBNL, Berkeley, California)
The ALS storage ring 500 MHz RF system uses two
re-entrant accelerating cavities powered by a single
320kW PHILLIPS YK1305 klystron. During several
years of initial operation, the RF cavities were not
equipped with effective passive HOM damper systems.
Longitudinal beam stability was achieved through
cavity temperature control and the longitudinal
feedback system (LFB), which was often operating at
the edge of its capabilities. As a result, longitudinal
beam stability was a significant operations issue at the
ALS. During two consecutive shutdown periods (April
2002 and 2003) we installed E-type HOM dampers on
the main and third harmonic cavities. These devices
dramatically decreased the Q-values of the longitudinal
anti-symmetric HOM modes. The next step is to damp
the rest of the longitudinal HOM modes in the main
cavities below the synchrotron radiation damping level.
This will hopefully eliminate the need for the LFB and
set the stage for a possible increase in beam current.
The ?waveguide? type of HOM damper was the only
option that didn?t significantly compromise the
vacuum performance of the RF cavity. The design
process and the results of the low level measurements
of the new waveguide dampers are presented in this paper.
*Work supported by the Director, Office of Science, Office
of Basic Energy Sciences, Materials Science and
Engineering Division, of the Department of Energy under
contract No. DE-AE03-76SF00098
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
19-512 - Industrial Production of the Eight Normalconducting 200 MHz ACN Cavities for the LHC
Roberto Losito, Jean Paul Bacher, Enrico Chiaveri,
Raymond Hanni, Trevor Paul Linnecar, Sebastien Marque,
Joachim Tuckmantel (CERN, Geneva)
The LHC-ACN RF system consists of 8 normal-conducting
cavities and is designed to reduce beam losses in the LHC
when injecting beams with longitudinal emittance > 0.7 eVs
from the CERN SPS. The cavity design took into account
the possibility of recuperating all the "ancillary" equipment
(tuners, fundamental mode damper, High Order Mode
(HOM) couplers) from the old CERN SPS 200MHz system.
The cavities are made from OFE copper. The original
ingots, procured in Austria, have been forged and preformed by pressing them with a 20 tons press, following a
procedure defined and adapted for the unusual dimensions
of these pieces. The raw components thus obtained were
machined and then welded together with an electron beam.
In order to get a good repeatability of the fundamental mode
frequency across the eight cavities, a procedure has been
established with the contractor for the final machining and
welding leading to a spread in frequencies below ±20 kHz
(< 0.01%). The cavities will be installed in the LHC when
losses at high intensities become significant. In the
meantime they are undergoing a surface treatment to clean
the RF surface and will be stored.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
20-516 - Accelerating RF Station for HIRFL-CSR,
Lanzhou, China
Grigory Yakovlevich Kurkin, Alexey Anatolyevich
Kondakov, Mikhail Kondaurov, Sergey Alexandrovich
Krutikhin, Sergey Viktorovich Motygin, Arkady Nikolaevich
Selivanov (BINP, Novosibirsk), Zhe Xu, Wenzhi Zhang
(IMP, Lanzhou)
In accordance with the plan of cooperation with the Institute
of Modern Physics (IMP), Lanzhou, China, the Budker
Institute of Nuclear Physics (BINP), Novosibirsk, Russia
has produced and supplied the accelerating RF station for
the multipurpose Cooling Storage Ring system (CSR),
which is being constructed at IMP. The RF station had been
tested at IMP site and now is installed into main ring of the
facilities. The RF station operates in the frequency range of
0.25 &#8211; 1.7 MHz. Maximum accelerating voltage is 8
kV. The resonance frequency of the RF cavity is tuned in
the whole frequency range by biasing of ferrites, which are
used in the cavity. The pressure in the cavity vacuum
chamber is lower, than 3E-11 mbar. RF cavity, RF
generator, and power supplies are made in one module.
Maximum output power of the RF generator is 30 kW. The
RF station control is based on Compact PCI bus and
provides all functions of RF station control and monitoring.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
21-517 - RF Station for Stacking of Ion Beam for
HIRFL-CSR, Lanzhou, China
Grigory Yakovlevich Kurkin, Alexey Anatolyevich
Kondakov, Mikhail Kondaurov, Sergey Alexandrovich
Krutikhin, Sergey Viktorovich Motygin, Arkady
Nikolaevich Selivanov (BINP, Novosibirsk), Zhe Xu,
Wenzhi Zhang (IMP, Lanzhou)
The Budker Institute of Nuclear Physics, Novosibirsk
(BINP), Russia has produced and supplied a RF station
to the Institute of Modern Physics (IMP), Lanzhou,
China for the multipurpose Cooling Storage Ring
system, which is being constructed there. The RF
station will be used for stacking of ion beam in the
main ring of the system. The RF station was tested at
the IMP site and installed into the main ring. The RF
station has RF cavity and RF generator with power
supplies. Frequency range of RF station is 6.0
&#8211; 14.0 MHz, maximum gap voltage of RF
cavity is 20 kV. Maximum output power of the RF
generator is 25 kW. The RF station control is based on
the Compact PCI bus and provides all functions of RF
station control and monitoring. Pressure of residual gas
in the RF cavity vacuum chamber is lower than 2E-11
mbar.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
22-699 - Numerical Investigation on the 500 MHz
ELETTRA Power Coupler
Cristina Pasotti, Paolo Craievich, Alessandro Fabris,
Giuseppe Penco, Michele Svandrlik (Sincrotrone
Trieste S.C.p.A., Basovizza, Trieste)
Due to the high input power required to feed a resonant
cavity, the RF input coupler is a critical component for
the reliability of an RF system. The 500 MHz RF input
coupler for the ELETTRA cavities was specified for
150 kW input power. It is important to investigate the
performance limits of the coupler in view of increasing
RF power requirements. The coupler's maximum peak
field and dissipation versus the input power have been
studied by means of the numerical simulator HFSS.
Possible improvements to the existing design have
been investigated. The optimization has to take into
consideration the following requirements: convenient
power transmission efficiency, RF matching, suitable
coupling coefficient, negligible perturbation on cavity
voltage, moderate operating temperature and stress.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
23-709 - RF System for Compact Medical Proton
Synchrotron
Zhigao Fang, Kazumi Egawa, Kuninori Endo (KEK,
Ibaraki)
The rf system has been developed for the compact
medical proton synchrotron. The rf system will be
operated in pulse mode with the fundamental rf
frequency sweeping from 1.6 to 15 MHz during the
acceleration time of 5 ms. The required rf cavity
voltage is a function of acceleration time too, with the
voltage of fundamental varying from 13 to 6 kV. Besides,
high order harmonics are also considered to apply to the rf
system, and the cavity peak voltage varying from 20 to 9 kV
during the acceleration time is expected. The performance of
the rf system is being studied and will be presented.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
24-803 - Combining Cavity For RF Power Sources:
Computer Simulation And Low Power Model.
Emma Wooldridge, Brian Todd (CCLRC/DL/ASTeC,
Daresbury, Warrington, Cheshire)
A combining cavity for RF power sources has been
investigated as a way of saving space, in comparison to
waveguides, and as a way of combining power with graceful
degradation if one or more component were to fail. The
cavity has been investigated as the maximum power output
of an Inductive Output Tube (IOT) for CW is 80KW at
500MHz and a proposed output of 20KW at 1.3GHz and
most RF systems for particle accelerators require much
more than this. Although 1.3GHz klystrons do exist they
are vastly more expensive to purchase and maintain. Also
the down time could be minimised to minutes in the even of
a single IOT failure where as a klystron has a minimum
downtime of several days in the event of a failure. Initially
the cavity and its inputs were simulated in CSTs?
Microwave studio. After optimising the cavity to ensure the
minimum reflection at the input ports and maximum
transmission at the output port, a low power model was then
created from aluminium. Signal generators were used to
power the model and a network analyser was used to check
the output. The model was used to compare the results
gained from the computer simulation and to obtain results
from asymmetric positioning of the ports, which was not
possible in the simulation.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
25-994 - Upgrade and Commissioning of the LNLS RF
System
Ruy H.A. Farias, Claudio Pardine (LNLS, Campinas)
In this paper we present a report on the commissioning of
the new RF system of the electron storage ring of the
brazilian synchrotron radiation facility (LNLS).
FINEP
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
26-1118 - A New Damped Cavity with Parallel-plate
Radial Lines
Tadashi Koseki (RIKEN/RARF/BPEL, Saitama), Masaaki
Izawa, Shogo Sakanaka, Takeshi Takahashi, Kensei
Umemori (KEK, Ibaraki)
We present a new 500 MHz HOM (Higher-Order Modes)
damped cavity for high brilliance synchrotron radiation
sources. The design is based on the damped cavity, which is
operated at the Photon Factory storage ring in KEK. The PF
cavity has a large hole beam duct (140 mm in diameter), a
part of which is made of a silicon carbide (SiC) microwave
absorber. The new cavity, proposed in this paper, has
parallel-plate radial transmission lines on the beam duct
instead of the SiC beam duct. The outer end of the radial
line is terminated by SiC absorbers. The HOMs, extracted
from the center part of the cavity through the beam
duct, propagate in the radial line and are dissipated in
the absorber. The accelerating mode is not affected by
the radial line damper since the frequency is
sufficiently below the cutoff of the 140-mm beam duct.
In this paper, optimized design of the radial line
damper and damping properties for HOMs are
described in detail.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
27-1137 - Studies on Maximum RF Voltages in
Ferrite-tuned Accelerating Cavities
Klaus Kaspar, Hans Guenter Koenig, Thomas
Winnefeld (GSI, Darmstadt)
The GSI SIS100 project requires very high accelerating
voltages. With ferrite-tuned synchrotron cavities the
gap voltage is often strongly limited by the Q-loss
effect appearing at medium dc bias fields. At low bias
fields, considerably higher voltages can be reached,
however. The maximum usable amplitudes over the
bias region have been studied. At zero bias, the ferrites
could be driven to more than a factor 3 above the Qloss limit. Except overheating, no other problems
appeared. With increasing bias, the maximum
amplitudes decrease continuously to the Q-loss level.
In this fall-off region there is still a tuning factor up to
2.5 available, with rf flux densities by at least a factor 2
above the Q-loss level. Measurements on small
samples of the ferrite material used in the GSI cavities
could be verified very well in a full-size cavity, for the
most part. The tests were mainly limited by the
available anode voltage and the fear of damaging the
cavity. It seems possible, to generalize the main results
for other ferrite materials, also. Based on the results, a
possible scenario for the SIS100 rf system is given.
Additionally, the results lead to an alternative cavity
design for higher voltages, which is described as well.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
28-1140 - Upgrade of KEKB RF System for SuperKEKB
Kazunori Akai, Tetsuo Abe, Kiyokazu Ebihara, Takaaki
Furuya, Shigeru Isagawa, Tatsuya Kageyama, Shinji
Mitsunobu, Hiroshi Nakanishi, Masaaki Ono, Hiroshi
Sakai, Masaaki Suetake, Yasunao Takeuchi, Shin-ichi
Yoshimoto (KEK, Ibaraki)
For the design of the Super-KEKB RF system, very
high beam currents of 9.4A in LER and 4.1A in HER
as well as a short bunch length of 3mm must be taken
into account. The existing RF system of KEKB with
the normal-conducting ARES and superconducting
cavities will be upgraded to meet the requirements for
Super-KEKB. Key issues are to suppress the coupledbunch instability due to a large detuning of the
accelerating mode, to improve the HOM dampers and
couplers, and to provide a large amount of RF power to
the beams. In addition, an RF system for the crabcrossing will be developed, which is expected to
increase the luminosity by several times. In this paper
we describe the design of the RF system for SuperKEKB.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
29-1166 - High Field Gradient Cavity for J-PARC 3 GeV
RCS
Chihiro Ohmori, Shozo Anami, Eizi Ezura, Keigo Hara,
Yoshinori Hashimoto, Akira Takagi, Masahito Yoshii (KEK,
Ibaraki), Alexander Schnase, Fumihiko Tamura, Masanobu
Yamamoto (J-PARC /JAERI, Tokai-Mura, Naka-Gun,
Ibaraki-Ken)
A new type of rf cavity will be used for J-PARC project. To
minimize the beam loading effects, the quality factor of the
core stack is increased by a cut core configuration. High
power test of the rf system has been performed.
Temperature rise around the cut surface of the cores were
observed. It is minimized by improving the cooling
efficiency.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
30-1282 - A Low Noise RF Source for RHIC
Thomas Hayes (BNL, Upton, Long Island, New York)
The Relativistic Heavy Ion Collider requires a low noise rf
source to ensure that beam lifetime during a store is not
limited by the rf system. The beam is particularly sensitive
to noise from power line harmonics. Additionally, the rf
source must be flexible enough to handle the frequency
jump required for rebucketing (transferring bunches from
the acceleration to the storage rf systems). This paper will
describe the design of a Direct Digital Synthesizer (DDS)
based system that provides both the noise performance and
the flexibility required.
Work performed under the auspices of the US Department
of Energy
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
31-1345 - Simulation of Dark Currents in X-band
Accelerator Structures
Karl Leopold Freitag Bane, Valery Dolgashev, Gennady
Stupakov, Juhao Wu (SLAC, Menlo Park, California)
In high gradient accelerator structures, such as those used in
the main linac of the GLC/NLC, electrons are emitted
spontaneously from the structure walls and then move under
the influence of the rf fields. In this report we study the
behavior of this "dark current" in X-band accelerator
structures using a simple particle tracking program and also
the particle-in-cell program MAGIC. We address questions
such as what is the sensitivity to emission parameters, what
fraction of dark current is trapped and reaches to the end of
a structure, and what are the temporal, spatial, and spectral
distributions of dark current as functions of accelerating
gradient.
Work supported by Department of Energy contract
DE--AC03--76SF00515
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
32-1376 - RF Field Measurements on an S-band Gun
Stephen Michael Gierman (SLAC, Menlo Park, California)
The Gun Test Facility at SLAC operates a 1.6-cell, S-band
rf photoinjector. The design of this gun is similar to the one
proposed for the Linac Coherent Light Source. An
issue of practical concern when commissioning and
operating these guns is establishing and knowing the
field-amplitude ratio between accelerating fields in the
first and second cells. This paper describes a cathodeplate tuning technique for manipulating the field ratio.
Extensive bench-test measurements have been
performed on the GTF gun, using a network analyzer
and perturbative bead measurements. The technique
was found to be sensitive and stable. Simulations with
the 2-D code Superfish compare favorably with the
bead measurements. We have also installed capacitive
probes to sample the field in each cell, and have
calibrated the probes with the bead measurements. The
probes allow us to measure the field ratio during
normal high-power operation, and also when tuning the
gun under low-power, high-vacuum conditions.
This work was supported by the US Department of
Energy, contract No. DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
33-1438 - PEP-II RF System Operation and
Performance
Peter McIntosh, Ron Akre, Mike Browne, Alan Hill, Bo
Hong, Rusty Humphrey, Ray Larsen, Dmitry
Teytelman, Pacak Vojtech (SLAC, Menlo Park,
California)
The Low Energy Ring (LER) and High Energy Ring
(HER) RF systems have operated now on PEP-II since
July 1998 and have assisted in breaking all design
luminosity records back in June 2002. Luminosity on
PEP-II has steadily increased since then as a
consequence of larger e+ and e- beam currents being
accumulated. This has meant that the RF systems have
inevitably been driven harder, not only to achieve these
higher stored beam currents, but also to reliably keep
the beams circulating whilst at the same time
minimizing the number of aborts due to RF system
faults. This paper details the current PEP-II RF system
configurations for both rings, as well as future upgrade
plans spanning the next 3-5 years. Limitations of the
current RF system configurations are presented,
highlighting improvement projects which will target
specific areas within the RF systems to ensure that
adequate operating overheads are maintained and
reliable operation is assured.
Work supported by Department of Energy contract DE-AC03--76SF00515
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
34-1461 - The SPEAR3 RF System
Peter McIntosh, Alan Hill, Pacak Vojtech (SLAC,
Menlo Park, California), Sanghyun Park, James J
Sebek (SLAC/SSRL, Menlo Park, California)
SPEAR2 was upgraded in 2003, to a new 3rd
Generation Light Source (3GLS) enabling users to take
better advantage of almost 100x higher brightness and
flux density over its predecessor SPEAR2. As part of
the upgrade, the SPEAR2 RF system has been revamped from its original configuration of one 200 kW
klystron feeding a single 358.5 MHz, 5-cell aluminum
cavity; to a 1.2 MW klystron feeding four 476.3 MHz, HOM
damped copper cavities. The system installation was
completed in late November 2003 and the required
accelerating voltage of 3.2 MV (800 kV/cavity) was very
rapidly achieved soon after. This paper details the SPEAR3
RF system configuration and its new operating
requirements, highlighting its installation and subsequent
successful operation.
Work supported by the U.S. Department of Energy under
contract DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
35-1466 - 201.25 Mhz Cavity Design and Fabrication for
MUCOOL/MICE
Derun Li (LBNL/AFR, Berkeley, California), Larry Phillips,
Robert Rimmer, Genfa Wu (Jefferson Lab, Newport News,
Virginia), John William Staples, Steve Virostek, Michael
Zisman (LBNL, Berkeley, California), Don Summers
(Mississippi University, Mississippi
We report recent progress on a high-gradient closed-cell
201.25 MHz cavity design and fabrication for the
MUCOOL/MICE experiments. To accelerate a shortlifetime muon beam that is created with large 6-D phase
space, a cavity with the highest possible RF gradient and
with large irises is needed. As the cavity must operate in a
few-Tesla magnetic field, it must be normal-conducting. For
201.25 MHz cavities in a nominal cooling channel, an
accelerating gradient of up to 17 MV/m is required. To
accommodate large size muon beams while maximizing
cavity shunt impedance, we adopt a rounded corner pillboxlike profile with the open beam iris terminated by thin,
curved beryllium foils so as to enhance the on-axis
accelerating field. Cavity fabrication began with the
creation of two half-shells by spinning a pair of copper
sheets against a form that has been machined with the cavity
design profile. The two half-shells are joined using a
circumferential e-beam weld to produce the cavity body.
We also present conceptual designs and fabrication methods
for the cavity tuner mechanism and the RF loop coupler.
Preliminary measurements of cavity frequency and shell
profiles will be presented.
This work is supported by the U.S. Department of Energy
under contract DE-AC03-76SF00098
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
36-1491 - The Experiences of Operation and
Performance about the 500MHz CW Klystrons at the
PLS Storage Ring
Jaeseok Yang, Myung-Hwan Chun, Yeung-Jin Han, SangHoon Nam, In Ha Yu (PAL, Pohang)
There are four RF stations to supply the energy to electron at
the storage ring of the Pohang Light Source(PLS). From the
beginning of the operation of RF system, 500MHz
60kW(CW) klystrons have been operated. As the operation
time of the tubes are increased, their performances are
decreased. Therefore three 60kW tubes were replaced with
the same model and two 75kW klystrons were replaced with
60 kW klystrons so far. Nowadays two 75 kW and two 60
kW klystrons are operated in the RF system of PLS. Our
experiences of the klystron operation and their general
performance are described in this paper.
Work supported by the Ministry of Science and
Technology (MOST)
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
37-1603 - Series Fabrication Technologies for
Normalconducting Linac and Storage Ring Cavities
Peter vom Stein, Kai Dunkel, Bernd Griep, Michael
Pekeler, Christian Piel, Hanspeter Vogel (ACCEL,
Bergisch Gladbach)
Twelve HOM damped 476 MHz single cell cavities
have been delivered for PEP II and the production of
several 805 MHz CCL modules for SNS has recently
been finalised by ACCEL Instruments. Based on those
two examples, required key technologies for cavity
production will be introduced. Final prove of
successful manufacturing is given by low level rf
measurements. Results of those measurements for
above mentioned projects will be presented within this
paper.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
38-1632 - Fabrication of X-band accelerating
Structures at FERMILAB
Tug Tacku Arkan, Harry Carter, David Finley, Ivan
Gonin, Timergali Khabibouline, Shekhar Mishra,
Gennady Romanov (Fermilab, Batavia, Illinois)
The RF Technology Development group at Fermilab is
working together with the NLC and GLC groups at
SLAC and KEK on developing technology for room
temperature X-band accelerating structures for a future
linear collider. We built seven 60cm long, high phase
advance, detuned structures (HDS or FXB series).
These structures have 150 degrees phase advance per
cell, and are intended for high gradient tests. The
structures were brazed in a vacuum furnace with a
partial pressure of argon, rather than in a hydrogen
atmosphere. We have also begun to build 60cm long,
damped and detuned structures (HDDS or FXC / FXD
series). So far, we have built 3 FXC structures. Our
goal is to build 4 FXC and 2 FXD structures for the 8pack test at SLAC by the end of March 2003, as part of
the GLC/NLC effort to demonstrate the readiness of
room temperature RF technology for a linear collider.
This poster describes the RF structure factory
infrastructure (clean rooms, vacuum furnaces, vacuum
equipment, RF equipment etc.), and the fabrication
techniques utilized (the machining of copper cells /
couplers, quality control, etching, vacuum brazing,
cleanliness requirements etc.) for the production of
FXB and FXC structures.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
39-1802 - Electrons Beam Dynamics of the 100MeV
Preinjector Helios for the SOLEIL Synchrotron
Andrew Setty (THALES, Colombes)
A 100 MeV electron linac is under construction, in
order to inject into the booster synchrotron of SOLEIL.
The linac is designed to work according to two
operation modes : a short pulse mode (2 ns - 0,5 nC)
and a long pulse mode (300 ns - 8 nC). Calculation of
the beam dynamics, using our selfmade code PRODYN, has
been carried out from the gun to the end of the linac. Special
care has been taken on the gun design to avoid an
overfocusing outcoming beam in order to obtain a final low
emittance. Calculations results are given.
Type of presentation requested: Poster
Classification: [T06] Room Temperature RF
40-228 - High Current Superconducting Cavities at
RHIC
Rama Calaga, Ilan Ben-Zvi, Yongxiang Zhao (BNL, Upton,
Long Island, New York), Jacek Sekutowicz (Jefferson Lab,
Newport News, Virginia)
A five-cell high current superconducting cavity for the
electron cooling project at RHIC is under fabrication.
Higher order modes (HOMs), one of main limiting factors
for high current energy-recovery operation, are under
investigation. Calculations of HOMs using time-domain
methods in Mafia will be discussed and compared to
calculations in the frequecy domain. A possible motivation
towards a 2x2 superstructure using the current five-cell
design will be discussed and results from Mafia will be
presented. Beam breakup thresholds determined from
numerical codes for the five-cell cavity as well as the
superstructure will also be presented.
Work performed under the auspices of the US Department
of Energy
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
41-329 - Shielded Bellows in Cryogenic Systems
Yongxiang Zhao, Harald Hahn (BNL, Upton, Long Island,
New York)
Bellows are frequently required in accelerators and
colliders. Usually RF-shields with spring fingers are
employed to screen the bellows. The lack of accessibility in
cryogenic systems can be a problem and asks for alternate
solutions to eliminate possible overheating, sparking, etc.
that occurred in intensive beams. This note addresses a new
kind of RF shield, which uses capacitive contact instead of
mechanical contact. The analysis, as well as numerical
example of a superconducting cavity structure, show that the
capacitive RF shield satisfies the impedance requirements of
both beam and HOMs. The capability of thermal isolation is
also analyzed.
Work performed under the auspices of the U.S. Department
of Energy.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
42-432 - Low and Medium Beta Superconducting
Cavities
Alberto Facco (INFN/LNL, Legnaro, Padova)
The use of low- and intermediate-beta superconducting
cavities, once confined to low current heavy ion linacs, is
steadily increasing in accelerators. The progress in this
technology allowed a significant increase in cavity
performance during the last 10 years; a large number of
resonators, with different geometries, frequencies and gap
numbers have been built for a large variety of applications
and the development is still going on. The main boost is
given by new projects of radioactive beam facilities and
high power proton accelerators worldwide. While the
advantages of SC resonators, compared with normal
conducting structures, are rather well established in
high-beta linacs, this is not always the case at low-beta.
The choice of the optimum transition beam energy in a
linac, where superconducting cavities should replace
the room temperature ones, requires a careful
evaluation that depends on the linac specifications.
Type of presentation requested: This is an Invited
Oral Presentation
Classification: [T07] Superconducting RF
43-433 - Achievement of 35 MV/m in the TESLA
Superconducting Cavities Using Electropolishing as
a Surface Treatment
Lutz Lilje, Denis Kostin, Axel Matheisen, Wolf-Dietrich
M&#246;ller, Dieter Proch, Detlef Reschke, Peter
Schm&#252;ser, Stefan Simrock, Krzysztof Twarowski
(DESY, Hamburg), Eiji Kako, Kenji Saito (KEK,
Ibaraki)
The Tera Electronvolt Superconducting Linear
Accelerator TESLA is the only linear electron-positron
collider project based on superconductor technology
for particle accelaration. In the first stage with 500
GeV center-of-mass energy an accelerating field of
23.4MV/m is needed in the superconducting niobium
cavities which are operated at a temperature of 2 K and
a quality factor Q0 of 10^10. This performance has
been reliably achieved in the cavities of the TESLA
Test Facility (TTF) accelerator. The upgrade of TESLA
to 800 GeV requires accelerating gradients of 35
MV/m. Using an improved cavity treatment by
electrolytic polishing it has been possible to raise the
gradient to 35 - 43 MV/m in single cell resonators.
Here we report on the successful transfer of the
electropolishing technique to multi-cell cavities.
Presently four nine-cell cavities have achieved 35
MV/m at Q_0 = 5 × 10^9, and a fifth cavity could be
excited to 39 MV/m. In two high-power tests it could
be verified that EP-cavities preserve their excellent
performance after welding into the helium cryostat and
assembly of the high-power coupler. One cavity has
been operated for 1100 hours at the TESLA-800
gradient of 35 MV/m and 57 hours at 36 MV/m
without loss in performance.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
44-525 - Surface Morphology at the Quench Site
St&#233;phane Berry, Claire Antoine
(CEA/DSM/DAPNIA, Gif-sur-Yvette)
It has been demonstrated recently that local magnetic
field enhancement can originate from roughness (e.g.
steps at grain boundaries). We are willing to investigate
if the quench observed in superconducting niobium
cavities can be related to such morphological defects.
We recently developed two kinds of tool. 1) A replica
technique that allows to reproduce the internal surface
of cavities (non destructive testing). 2) A
morphological analysis tool. Classical roughness
measurements are not adapted to determine local
curvature radius.This paper describes a new topological
approach aiming at a better characterization of the
surface morphology. We also present results of this
technique applied to replica taken from cavities at the
quench site.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
45-566 - Dynamic Lorentz Force Detuning Studies in
TESLA Cavities
Valeri Ayvazyan, Stefan Simrock (DESY, Hamburg)
Dynamic detuning of the superconducting rf cavities due to
Lorentz force induced mechanical excitation is a critical
concern since the magnitude can approach the cavity
bandwidth and require significant additional rf power for
field control. In this paper, the influence of high accelerating
fields on the resonance frequency in superconducting
TESLA cavities is discussed. Cavities at the TESLA Test
Facility have been operated at the design operating gradient
close to 25 MV/m. It is shown that Lorentz force detuning
constant factors are different for different cavities,
significant spread have been observed.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
46-570 - Electromagnetic Design of New RF Power
Couplers for the S-DALINAC
Marco Kunze, Wolfgang F.O. M&#252;ller, Thomas
Weiland (TEMF, Darmstadt), Hans-Dieter Gr&#228;f,
Achim Richter (TU Darmstadt, Darmstadt)
New rf power couplers for the Superconducting Darmstadt
Linear Accelerator (S-DALINAC) injector have to be
designed to transfer rf power up to 2 kW to the electron
beam. This allows injector operation at beam currents from
0.15 mA to 0.2 mA and electron energies up to 14 MeV.
The new couplers should possibly provide a variable
external Q in the range from 5E6 to 3E9 and a small
transverse kick. A variable coupling is needed to allow for
perfect matching in the case of beam loading and when no
beam is present, respectively. The second operation stage is
used for cavity diagnostics. The asymmetric field
distribution of the couplers generates emittance growth of
the electron beam and therefore the transverse kick has to be
minimized. Electromagnetic simulations are applied to
investigate different coupler designs and to localize possible
problems at an early stage. Cavity external Q and transverse
kick can be calculated from 3D electromagnetic eigenmode
solutions. The present coaxial-coaxial input couplers at the
S-DALINAC are limited to power operation below 500 W
under full reflection. Therefore, to reach power operation up
to 2 kW two possible new realizations of low-kick
waveguide couplers for the S-DALINAC injector are
presented, namely a single-waveguide and a twin-waveguide
coupler.
Work supported by the DFG under contract SFB 634
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
47-571 - First Year of Operation of SUPER-3HC at
ELETTRA
Giuseppe Penco, Paolo Craievich, Alessandro Fabris,
Cristina Pasotti, Michele Svandrlik (Sincrotrone Trieste
S.C.p.A., Basovizza, Trieste)
Since July 2003 a superconducting third harmonic cavity
has been in routine operation at ELETTRA. When the cavity
is activated the stored electron bunches are lengthened by
about a factor of three. The related longitudinal Landau
damping has allowed first time operation at 320 mA,
2.0 GeV with a beam completely free of longitudinal
coupled bunch instabilities. With the cavity active the
lifetime at 320 mA, 2.0 GeV is three times the
theoretical value for nominal bunch length. The
increase in beam stability and lifetime contributed
significantly to enhance the brightness and the
integrated flux of the source. We will further discuss
the operating experience with the superconducting
cavity and the cryogenic system, analyzing the impact
of the new system on machine operation and uptime.
Finally we will also report on the characterization of
the cavity performance for different filling patterns of
the storage ring and relate the results to preliminary
beam-cavity interaction studies.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
48-606 - HoBiCaT --- The Superconducting RF
Cavity Test Facility at BESSY
Jens Knobloch, Wolfgang Anders, Axel Neumann, Dirk
Pfl&#252;ckhahn, Michael Schuster (BESSY GmbH,
Berlin)
BESSY has recently constructed the HoBiCaT
cryogenic test facility for superconducting TESLA
cavity units, including all ancillary devices (helium
tank, input coupler, tuner, magnetic shielding). It is
designed to house two such units in a configuration
similar to that envisaged for the superconducting CW
linac of the BESSY FEL. These units are presently
being fabricated, prepared and assembled by industry.
HoBiCaT will be used to address many of the issues
that must be considered prior to finalizing the design of
the proposed linac. Rapid turn-around-tests permit the
investigation of items such as RF regulation,
microphonic
detuning
and
cryogenic
parameters/achievable pressure stability. These test
will also serve as the first step towards qualifying the
industrial production of assembled cavity units. The
commissioning of HoBiCaT is scheduled for Spring
2004 and the current status is presented here.
Funded by the BMBF and the Land Berlin
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
49-609 - Cryogenic Considerations for CW
Operation of TESLA-type Superconducting Cavity
Modules for the BESSY FEL
Jens Knobloch, Wolfgang Anders, Xiang Yu (BESSY
GmbH, Berlin)
The proposed BESSY FEL uses a CW superconducting
driver linac to provide acceleration up to 2.3 GeV. Its
design is based on
well-established TESLA
technology, originally intended for heat loads of order
1 W/m at 2.0 K. CW operation increases this load to
levels of order 15 W/m at 1.8 K for a total heat load of
3 kW at 2.3 GeV (given conservative assumptions for
the attainable Q-factor). Presented here is an analysis
of the cryogenic layout, including two-phase-flow
simulations of the 1.8-K helium which help identify the
changes needed for reliable CW operation. A modified
``CW'' module and helium distribution scheme is proposed.
Funded by the BMBF and the Land Berlin
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
50-611 - RF Control of the Superconducting Linac for
the BESSY FEL
Jens Knobloch, Axel Neumann (BESSY GmbH, Berlin)
In the BESSY-FEL superconducting linac, precise RF
control of the cavities' voltage is imperative to maintain a
bunch-to-bunch time jitter of less than 50 fs for
synchronization in the HGHG section. The average beam
loading is less than 1.5 kW/m and the cavity bandwidth is
small so that high-gain RF feedback is required. Noise, in
particular microphonic detuning, strongly impact the
achievable level of control. Presented here are simulations
of the cavity-feedback system, taking into account beam
loading and noise sources such as measurement noise,
microphonics and injection jitter. These simulations are
used to estimate the resultant time and energy jitter of the
bunches as they enter the HGHG section of the BESSY
FEL.
Funded by the BMBF and the Land Berlin
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
51-863 - Multipactor Studies of Electron Multipacting in
CESR Type Rectangular Waveguide Couplers
Philippe Goudket, Mike Dykes (CCLRC/DL/ASTeC,
Daresbury, Warrington, Cheshire), Hasan Padamsee
(Cornell University, Ithaca, New York), Sergey
Belomestnykh, Rong-Li Geng (LEPP, Ithaca, New York),
Richard Carter (Microwave Research Group, Lancaster)
The latest results from an experimental waveguide section,
as well as simulations from a model of electron multipacting
using the MAGIC PIC code, are discussed. Tests were
carried out on a new waveguide section that included
enhanced diagnostics and the possibility of changing surface
materials and temperature. Those tests evaluated grooves,
ridges and surface coatings, such as TiN and a TiZrV NEG
coating, as methods of multipactor suppression. The
conclusion remains that the most effective method to
achieve complete multipactor suppression remains the
application of a static magnetic bias of approximately 10G.
The experiments also provided good data sets that can be
used to verify the accuracy of simulations. Simulations of
the waveguide multipacting have been carried out and have
offered better understanding of electronic behaviour.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
52-884 - RF Cavity Options for the JLAB High-current
Energy-recovered FEL
Robert Rimmer, Peter Kneisel, Haipeng Wang, Genfa Wu
(Jefferson Lab, Newport News, Virginia), Jacek Sekutowicz
(DESY, Hamburg)
Future upgrades of the Jefferson Lab free electron laser
(FEL) presently under discussion would require one or more
orders of magnitude greater recirculating beam current (100
mA to 1A or more). Since energy recovery is assumed there
would not be a significant increase in RF power
requirements in the main machine, however higher-order
mode (HOM) driven beam break-up (BBU) is a major
concern. We discuss options for RF cavities for such a
machine that would provide very strong HOM damping
with a good real-estate gradient and high HOM power
capability. Such designs would also be suitable for
other applications such as electron coolers, electron-ion
colliders and other light sources.
This work was supported by DOE SURA Inc. and
ONR under Contract No. DE-AC05-84ER-40150 with
the U.S. Department of Energy.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
53-907 - Photoemission Properties of Lead
John Smedley, Triveni Srinivasan-Rao, John Warren
(BNL, Upton, Long Island, New York), Jacek
Sekutowicz (DESY, Hamburg; Jefferson Lab, Newport
News, Virginia), Richard Lefferts, Andrzej Lipski
(SBUNSL, Stony Brook, New York)
There is significant interest in the possibility of
building a super-conducting injector for high average
current accelerator applications. One candidate for
such a cavity design is superconducting lead. Such an
injector would be made considerably simpler if it could
be designed to use lead as the photocathode,
eliminating the need for Cesiated materials in the
injector. In this paper we present a study of the
photoemission properties of lead at several UV
wavelengths, including a study of the damage threshold
of electroplated lead under laser cleaning. A quantum
efficiency in excess of 0.1% has been achieved for a
laser cleaned, electroplated lead sample with a laser
wavelength of 193 nm.
This work was partially supported by DOE contracts
DE-AC02-98CH10886, DE-AC03-76SF00515 and
DE-FG02-97ER82336
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
54-1011 - The Progress of a DC-SC Photo-injector
at Peking University
Kui Zhao, Yuantao Ding, Senlin Huang, Xiangyang Lu,
Shengwen Quan, Lifang Wang, Baocheng Zhang
(PKU/IHIP, Beijing), Jia-er Chen (NSFC, Beijing)
A DC-SC photo-injector consisting of a DC Pierce gun
and a 1.3GHz 1+1/2 cell-superconducting cavity was
constructed and commissioned at Peking University.
The results of the RF and beam test are reported. The
progress in the development of the photo-cathode, the
driving laser system, the RF and Beam diagnostic
system are also reported and discussed.
Supported partly by Chinese Department of Science
and Technology under the National basic Research
Projects (No.2002CB713602) and by National Natural
Science Foundation of China (10075006)(19985001)
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
55-1123 - RF Property of the Prototype Cryomodule for
ADS Superconducting Linac
Eiji Kako, Shuichi Noguchi, Kenji Saito, Toshio Shishido
(KEK, Ibaraki), Nobuo Ouchi (JAERI/LINAC, Ibaraki-ken)
A prototype cryomodule containing two 9-cell
superconducting
cavities
of
beta=0.725
and
frequency=972MHz is being constructed under the
collaboration of Japan Atomic Energy Research Institute
(JAERI) and High Energy Accelerator Research
Organization (KEK) on the development of superconducting
LINAC for Accelerator Driven System (ADS). Design and
performance of RF components will be reported.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
56-1132 - Cryogenic Performance of the Prototype
Cryomodule for ADS Superconducting LINAC
Norihito Ohuchi, Eiji Kako, Shuichi Noguchi, Toshio
Shishido, Kiyosumi Tsuchiya (KEK, Ibaraki), Nobuo Ouchi
(JAERI/LINAC, Ibaraki-ken)
A
prottype
cryomodule
containing
two
9-cell
superconducting cavities of b=0.725 and f=972MHz is being
constructed under the collaboration of Japan Atomic Energy
Research Institute (JAERI) and High Energy Accelerator
Research Organization (KEK) on the development of
superconducting LINAC for Accelerator Driven System
(ADS). Cryogenic performances of the cryomodule and 2K
He-system will be reported.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
57-1146 - Construction of the Beta=0.31, 352 MHz
Superconducting Half-wave Resonator for the SPES
Project
Alberto Facco (INFN/LNL, Legnaro, Padova), Vladimir
Zviagintsev (TRIUMF, Vancouver)
The interest in low- and medium- beta superconducting
cavities is presently focused to future high intensity proton,
deuteron and heavy ion linacs. A particular application is
acceleration of cw and pulsed beams of variable q/A, which
requires cavities with a small number of gaps and excellent
mechanical stability. We have designed and constructed a 2
gap, 352 MHz SC half wave cavity aiming to similar
characteristics and fitting the requirements of the
intermediate-beta section of the LNL-SPES driver. The
status of the project and the first test results will be
presented.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
58-1150 - Construction of a 161 MHz, beta=0.16
Superconducting Quarter Wave Resonator with Steering
Correction for RIA
Alberto Facco (INFN/LNL, Legnaro, Padova), Terry L.
Grimm, Walter Hartung, Felix Marti, Richard York (NSCL,
East Lansing, Michigan), Vladimir Zviagintsev (TRIUMF,
Vancouver)
We have built a 161 MHz, b=0.16 superconducting Quarter
Wave Resonator with steering correction for the low beta
section of RIA. This bulk niobium, double wall cavity,
compatible with both separate vacuum between beam line
and cryostats or unified one, was designed in collaboration
between MSU-NSCL and LNL. The design is suitable for
extension to other frequencies, e.g. to obtain the 80
MHz, beta=0.085 cavity required in RIA. The shaped
drift tube allows correction of the residual QWR
steering that can cause emittance growth especially in
light ions; this could make this resonator a good
alternative to Half-Wave resonators in high intensity
proton-deuteron linacs, like the SPES injector project
at LNL. First test results will be presented.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
59-1212 - High Power Tests of The Beta=0.5 Five
Cell TRASCO Cavities
Angelo Bosotti, Massimo Bonezzi, Paolo Michelato,
Carlo Pagani, Roberto Paulon, Paolo Pierini
(INFN/LASA, Segrate (MI)), Bernard Visentin
(CEA/DSM/DAPNIA, Gif-sur-Yvette), Gianluigi
Ciovati, Peter Kneisel (Jefferson Lab, Newport News,
Virginia)
Two complete 5 cell superconducting cavities at b=0.5
have been designed and fabricated. The cavities have
been designed to minimize peak electric and magnetic
fields, with a goal of 8.5 MV/m of accelerating
gradient, at a Q > 5E9. The cavities are currently in the
testing stage and the results of the vertical tests will be
presented at this conference.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
60-1215 - Study of the Possibilities for
Manufacturing of the SVAAP Cavities by means of
Galvanoplastic Technique and Magnetron
Sputtering Methods
Larissa Mikhailovna Sevryukova (IHEP Protvino,
Protvino, Moscow Region)
The purpose of this report is to discuss development
and study of the technological possibilities for
manufacturing SC cavities on the base of Nb/Cu. We
use the galvanoplastic forming technique method and
magnetron sputtering method. It makes possible to
reduce the cost of the SC RF structures. They have a
higher stability during the operation at the cryogenic
temperatures, do not require special magnetic shields
and allow one to apply not only Nb, but also other SC
material on copper shells. We develop the equipment
for realization of these technologies and we give results
on these cavities.
Ministry of the Russian Federation for Atomic Energy,
Depertment for Atomic Science and Technology
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
61-1218 - Study of the Possibility for SVAAP
Energy Increase up to 15-20 MeV.
Igor Zvonarev (IHEP Protvino, Protvino, Moscow
Region)
Federate Problem Lab deals with the SC accelerator for
irradiation of High Tc ceramics SVAAP (Superconducting Vertical accelerator for Applied Purpose)
with energy 7.5 MeV. Now we need to develop the
energy up to 15-20 MeV. In this report special
attention has been given to the RF structure, its
geometry and technology. Definition of geometrical
parameters was based on the analysis of calculation results
of particle dynamics. RF structure for accelerator SVAAP-2
consists of three cavities: capture cavity of 3 cells and two
accelerating cavities of 9 cells each one. We hope, that the
use of two accelerating cavities and our new SC cavity
technology will allow us to improve energy up to 15-20
MeV.
Ministry of the Russian Federation for Atomic Energy,
Depertment for Atomic Science and Technology
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
62-1221 - Performances Improvement for the French
Multicell Superconducting Cavity Prototype Dedicated
to Proton LINAC Projects.
Bernard Visentin, Didier Braud, Jean Pierre Charrier, Yves
Gasser, Jean Pierre Poupeau, Dominique Roudier, Patrick
Sahuquet (CEA/DSM/DAPNIA, Gif-sur-Yvette),
S&#233;bastien Bousson, Herve Saugnac, Philippe Szott
(IPN, Orsay)
The CEA-Saclay / IPN-Orsay collaboration allowed to
develop a multicell superconducting cavity prototype (704
MHz - beta=0.65). Since the first experimental results [*],
achieved in a vertical cryostat and the horizontal one
CryHoLab, the accelerating field Eacc has been recently
improved up to 19 MV/m (Epeak = 43 MV/m - Bpeak = 83
mT - Q0 = 9.109) with a limitation by quench. This new
limitation took the place of the previous one, due to a non
understood phenomenon. The excellent performances of this
5-cell proton cavity validate the design, the technological
choices, the manufacturing and the cavity preparation
process. These results augur well for our future R&D
program on multicell superconducting cavities within the
European CARE/HIPPI framework.
CEA-Saclay, DSM/DAPNIA/SACM - 91191 Gif/Yvette FRANCE
[*] Proceedings of Particle Accelerator Conference (May
2003 - Portland - USA ) : TAB047 - p.1303
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
63-1246 - Recent Developments on Superconducting
b035 and b015 Spoke Cavities at IPN for Low and
Medium Energy Sections of Proton Linear Accelerators.
Guillaume Olry, Jean-Luc Biarrotte, Sebastien Blivet,
S&#233;bastien Bousson, Francois Carrey, Frederic
Chatelet, Daniel Gard&#232;s, Nourredine Hammoudi,
Tomas Junquera, Christophe Mi&#233;lot, Alex
M&#252;ller, Daniel Ruffier, Herve Saugnac, Philippe Sz
Spoke cavities studies leaded by IPN-Orsay, for both XADS
and EURISOL projects, are fully integrated within the 5th
and 6th European Framework Programs. During 2003,
several tests have been performed on the first b035 spoke
cavity prototype. They have demonstrated the great potential
of this type of cavity in term of RF performances (Eacc
max=12.5 MV/m at T=4.2 K) and mechanical behavior
(very low sensitivity to errors fabrication, good stiffness...).
Following the upgrade of our cryogenic facility, we have
tested, this spring, the cavity at 2 K. These new results will
be presented in this paper. In parallel, the fabrication of a
new spoke cavity (2-gap, 352 MHz, b015) has begun in
January. While keeping the same geometry than that of the
b035 cavity, we carried out significant changes on the
coupler port and stiffening system designs. We report
here in particular, RF calculations concerning the new
location of the coupler port (in order to minimize losses
due to magnetic field) and also, mechanical
calculations about the new stiffening ring. Finally, we
will present the preliminary thought on modular
cryomodule which are based on the ?short?
cryomodule concept used with the Quarter Wave
Resonators for the SPIRAL-2 project.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
64-1288 - Status of the Superconducting CHStructure
Holger Podlech, Horst Deitinghoff, Horst Klein,
Holger Liebermann, Ulrich Ratzinger, Andreas
Christoph Sauer, Rudolf Tiede (IAP, Frankfurt-amMain)
H-mode cavities (IH-DTL, IH-RFQ, 4-Vane-RFQ)
have been developed and operated successfully during
the last decades for ion acceleration. At the IAP
Frankfurt a new type of H-mode cavity, the CHstructure is under development. This multi cell drift
tube cavity is operated in the TE21- mode. Due to its
mechanical rigidity, room temperature as well as
superconducting
versions
can
be
realized.
Superconducting CH-structures might be used
especially for cw operated linacs in nuclear research
facilites and applied research projects like XADS or
IFMIF. A superconducting 352 MHz CH-structure
(beta=0.1) with 19 gaps will be available for first tests
in 2004. We present the status of the cavity and of the
new cryo laboratory in Frankfurt.
BMBF contract 06F134I
GSI
EU
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
65-1300 - Experience with Room Temperature
Conditioning and High RF Power Testing
Fundamental Power Couplers for the SNS
Superconducting Cavity Production.
Mircea Stirbet (Jefferson Lab, Newport News,
Virginia)
The Spallation Neutron Source (SNS) makes use of
medium beta (0.61) and high beta (0.81) cavities. For
the medium beta type, one prototype module plus 11
modules with a total of 36 cavities have being
assembled and 12 modules with 48 high beta cavities
are in the production line. Each cavity is equipped
with a fundamental power coupler similar in design
and manufacture. Before assembly on the cavity, all
couplers are prepared and tested on a dedicated 1 MW,
805 MHz room temperature test stand. Based on the
results obtained so far - all necessary medium beta
couplers are qualified and a sustained effort is
underway for the high beta couplers - this paper will
focus on the experience gained at Jefferson Laboratory
during RF conditioning and high power testing the
fundamental power couplers for the SNS cavity
production.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
66-1348 - Niobium Thin Film Cavity Deposition by ECR
Plasma
Genfa Wu, Larry Phillips, Anne-Marie Valente, Haipeng
Wang, Andy Wu (Jefferson Lab, Newport News, Virginia),
Tim Renk (Sandia National Laboratories, Albuquerque, New
Mexico)
Nb/Cu technology for superconducting cavities has proven
to be over the years a viable alternative to bulk niobium.
Energetic vacuum deposition is a very unique alternative
method to grow niobium thin film on copper. Single crystal
growth of niobium on sapphire substrate has been achieved
as well as good surface morphology of niobium on small
copper samples. The design of a cavity deposition system is
in development. This paper presents the exploratory studies
of the influence of the deposition energy on the Nb thin film
properties. Several possible venues to achieve Nb/Cu cavity
deposition with this technique are also discussed along with
the design of the cavity deposition setup under development.
This manuscript has been authorized by SURA, Inc. under
Contract No. DE-AC05-84ER-40150 with the U.S.
Department of Energy
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
67-1363 - Production and Performance of the CEBAF
Upgrade Cryomodule Intermediate Prototypes
Anne-Marie Valente, Edward Daly, Jean Roger Delayen,
Michael Drury, John Mammosser, Larry Phillips, Tom
Powers, Joseph P Preble, Charles Reece, Robert Rimmer,
Haipeng Wang (Jefferson Lab, Newport News, Virginia),
Catherine Thomas-Madec (SOLEIL, Gif-sur-Yv
We have installed two new cryomodules, one in the nuclear
physics accelerator (CEBAF) and the other in the Free
Electron Laser (FEL) of Jefferson Lab. The new
cryomodules consist of 7-cell cavities with the original
CEBAF cell shape and were designed to deliver gradients of
70 MV/module. Several significant design innovations were
demonstrated in these cryomodules. This paper describes the
production procedures, the performance characteristics of
these cavities in vertical tests, results of tests in the new
cryomodule test facility (CMTF) as well as the
commissioning in the CEBAF tunnel and FEL.
Performances and limitations after installation in the
accelerators are discussed in this paper along with
improvements proposed for future cryomodules.
U.S. Department of Energy,Contract No. DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
68-1392 - Cavity Process Monitoring and Investigations
utilizing Witness Samples to Reduce Field Emission
Tong Wang, John Mammosser, Larry Phillips, Charles
Reece, Robert Rimmer (Jefferson Lab, Newport News,
Virginia)
Although particulate contaminant has been identified as the
main cause of field emission, the lack of consistency in field
emission performance remains the dominating impediment
in cavity production at Jlab. We will present our latest
results in investigating field emission performance from
witness samples incorporated in certain cavity
production processes.
Work supported by the U.S. Department of Energy,
Contract No. DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
69-1405 - JLAB Hurricane Recovery
Andrew Hutton, Dana Arenius, Jay Benesch, Swapan
Chattopadhyay, Edward Daly, Venkatarao Ganni,
Omar Garza, Reza Kazimi, Ronald Lauze, Lia
Merminga, William Merz, Richard Nelson, William
Oren, Matthew Poelker, Tom Powers, Joseph P Preble,
Charles Reece, Ro
Hurricane Isabel, originally a Category 5 storm, arrived
at Jefferson Lab on September 18 with winds of only
75 mph creating little direct damage to the
infrastructure. However, electric power was lost for
four days allowing the superconducting cryomodules to
warm up and causing a total loss of the liquid helium.
The subsequent recovery of the cryomodules and the
impact of the considerable amount of opportunistic
preventive maintenance provides important lessons for
all accelerators complexes, not only those with
superconducting elements. The details of how the
recovery process was structured and the resulting
improvement in accelerator availability will be
discussed in detail.
This work supported by the U. S. Department of
Energy under contract DE-AC05-84ER40150
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
70-1530 - Magnesium Diboride as a Candidate
Material for Superconducting RF Structures
Tsuyoshi Tajima (LANL, Los Alamos, New Mexico)
Magnesium diboride (MgB2) was discovered to be
superconductive at 39 K in early 2001. Since then, a
number of studies have been carried out due to its
simplicity compared to the high-Tc materials such as
YBCO. One attractive feature for RF applications is
the absence of weak link behavior that has prevented
high-Tc superconductors from being applied to RF
structures. Recently, a MgB2 film has shown a surface
resistance lower than Nb at 4 K, demonstrating the
potential of exceeding the Nb cavity performance.
This paper presents test results on RF surface
resistance, its dependence on surface magnetic fields
and discuss the benefits of using this material for RF
structures.
US Department of Energy under contract W7405ENG-36
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
71-1531 - First Cryogenic Tests with a 2xFIVECELL Superstructure
Peter Kneisel, Gianluigi Ciovati, Genfa Wu (Jefferson
Lab, Newport News, Virginia), Jacek Sekutowicz
(DESY, Hamburg)
The concept of a superstructure for the acceleration of
a pulsed beam to an energy of 48 MeV has been
successfully demonstrated at DESY. Superstructures
can be employed for higher currents and cw operation as
needed for the next generation of FEL's at JLab. We have
built a model of such a superstructure by modifying two
existing CEBAF five-cell Cu cavities coupled to each other
via a half wave length long pipe. Four HOM couplers
attached to this superstructure resulted in strong damping of
the first few HOM pass-bands, sufficient for stable
acceleration of beams up to ~ 100 mA. Subsequently, we
have fabricated a Nb model of a 2 x five-cell superstructure
by modifying two existing CEBAF cavities. This
contribution reports about the first cryogenic tests of this
model.
This work was supported by DOE under contract No. DEAC05-84ER-40150
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
72-1604 - Custom Design of Medium Energy Linear
Accelerator Systems
Kai Dunkel, Bernd Griep, Christian Piel, Hanspeter Vogel,
Peter vom Stein (ACCEL, Bergisch Gladbach)
Based on customer requirements ACCEL Instruments is
designing and building medium energy turn-key Linear
Accelerator Systems for scientific applications. Within this
paper design and performance of third generation
synchrotron light source electron injector linacs will be
presented. Further the design of a medium energy light ion
linear accelerator will be discussed. This light ion
accelerator is designed with independently phased
superconducting rf cavities for cw operation and
acceleration of different particle species and a variable
Energy output.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
73-1683 - Superconducting RFQ's in the PIAVE Injector
Giovanni Bisoffi, Giorgio Bassato, Giampietro Bezzon,
Stefania Canella, Francesca Chiurlotto, Augusto Lombardi,
Anna Maria Porcellato, Serguei Stark (INFN/LNL, Legnaro,
Padova)
The PIAVE superconducting RFQ's were installed on the
linac line and connected to the TCF50 cryogenic system.
First results on the on-line resonator performance (e.g. Qcurves, amplitude and phase locking) are described.
Istituto Nazionale di Fisica Nucleare
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
74-1783 - Operation Experience with ALPI Nb/Cu QW
Resonators
Anna Maria Porcellato, Vincenzo Palmieri, Sergey Stark
(INFN/LNL, Legnaro, Padova)
The refurbishing, by replacing the Pb superconducting film
by Nb, of ALPI QW accelerating resonators was completed
in 2003. All the 52 cavities are now in operation showing a
large increase in the average accelerating field, which
exceeds 4.5 MV/m (21 MV/m pick electrical surface field).
The performance of renewed resonators has been increasing
with time reaching 6MV/m in the last produced units. The
increase in ALPI performance and the advantage in
conditioning and setting time obtained by the upgrading
process will be reported.
Type of presentation requested: Poster
Classification: [T07] Superconducting RF
75-413 - Comparison of Klystron and IOT
Abbasali Zolfaghari, Patrick MacGibbon, William
North (MIT/BLAC, Middleton, Massachusetts)
The MIT X-Ray Laser project, conceived to produce
output in the 0.3 to 100 nanometer range, is based on a
super-conducting 4-GEV linear accelerator, using 24
multi-cavity cryo-modules, each with its own dedicated
RF amplifier, operating at 1.3 GHz. The continuous
output of each amplifier is nominally 15 kW, with an
optional repetitive pulse-modulation mode of 0.1
second pulse duration at one pulse per second.
Although there are no fundamental restraints which
preclude the consideration of any RF amplifier type,
including solid-state or conventional triode or tetrode,
the most appropriate current technology includes the
Klystron and the IOT (Inductive Output Tube), also
known by the CPI trade-name, Klystrode. The
mechanisms by which the devices convert DC input
power into RF output power are discussed. The devices
are then compared with regard to availability
(developmental or off-the-shelf), conversion efficiency,
means of pulse-modulation, RF power gain, phase and
amplitude stability (pushing factors), and acquisition
and life-cycle costs.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
76-462 - Current Status of the Next Linear Collider
X-band Klystron Development Program
Daryl Sprehn, George Caryotakis (SLAC, Menlo Park,
California)
Klystrons capable of driving accelerator sections in the
Next Linear Collider have been developed at SLAC
during the last decade. In addition to fourteen 50 MW
solenoid-focused devices and a 50 MW Periodic
Permanent Magnet focused (PPM) klystron, a 500 kV
75 MW PPM klystron was tested in 1999 to 80 MW
with 3-microsecond pulses, but very low duty.
Subsequent 75 MW prototypes aimed for low-cost
manufacture by employing reusable focusing structures
external to the vacuum, similar to a solenoid
electromagnet. During the PPM klystron development,
several partners (CPI, EEV and Toshiba) have
participated by constructing partial or complete PPM
klystrons. After early failures during testing of the first
two devices, SLAC has recently tested this design
(XP3-3) to the full NLC specifications of 75 MW, 1.6
microseconds pulse length, and 120 Hz. This 14.4 kW
operation came with a tube efficiency of 50%. The
XP3 3 average and peak output power, together with
the focusing method, arguably makes it the most
advanced high power klystron ever built anywhere in
the world. Design considerations and the latest testing
results for these latest prototypes will be presented.
This work supported by the Department of Energy
under contract DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
77-526 - Low Output-Impedance RF System for 2nd
Harmonic Cavity in the ISIS Synchrotron
Toshiyuki Oki, Sadayoshi Fukumoto, Yoshiro Irie, Kenichi
Muto, Susumu Takano, Isao Yamane (KEK, Ibaraki),
Yanglai Cho, Jeffrey Craig Dooling, Douglas Horan, Robert
Kustom, Gerry McMichael, Mark Middendorf, Geoffery Pile
(ANL, Argonne, Illinois), Robin Ben
In the ISIS facility based at Rutherford Appleton Laboratory
(RAL) in the UK, second target station project was funded,
which requires to increase the current intensity by 1.5-times
(300 micro-A). Four 2nd harmonic RF cavities will be
installed in the ISIS synchrotron in order to increase the
trapping efficiency, and to mitigate the space charge
detuning. A very low output-impedance RF system for the
2nd harmonic cavity has been developed by the
collaboration between RAL, Argonne National Laboratory
(US) and KEK (Japan). The system comprises the 240 kW
triode as a final amplifier with plate-to-grid feedback path.
The measured output-impedance was less than 30 ohms over
the frequency range of 2.7 - 6.2 MHz, which agreed well
with calculations. High power test was also performed under
frequency swept mode at 50 Hz repetition. The operation
was almost stable, and more than 12 kVpp was obtained as
maximum. The voltage gain of the final amplifier was 25 30, which decreased gradually with frequency due to
decreasing input-impedance of triode. The beam test is
planned at ISIS in near future.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
78-589 - First Results with a Fast Phase and Amplitude
Modulator for High Power RF Application
Daniel Valuch, Hans Frischholz, Joachim Tuckmantel
(CERN, Geneva), Carsten Weil (AFT, Backnang)
In a high energy and high power superconducting proton
linac, it is more economical to drive several cavities with a
single high power transmitter rather than to use one
transmitter per cavity. This option has however the
disadvantage of not permitting to individually control each
cavity, which potentially leads to instabilities. Provided that
it can be built at a reasonable cost, a fast phase & amplitude
modulator inserted into each cavity feeder line can provide
the necessary control capability. A prototype of such a
device has been built, based on two fast and compact high
power RF phase-shifters, magnetically biased by external
coils. The design is described, together with the results
obtained at high and low power levels.
CERN
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
79-608 - Design and Construction of a High Voltage
Gridded Sheet Beam Klystron Power System
Michael Kempkes, Jeffrey Casey, Marcel Gaudreau
(Diversified Technologies, Inc., Bedford)
The Next Generation Linear Collider (NLC) will require
hundreds of X-band high power klystrons. These klystrons
are typically cathode pulsed at 500 kV and 265 A each, with
1.6 microsecond pulses of RF, and a complex microwave
delay line to achieve 400 ns RF pulses. Because the pulsed
voltage is so high, CV2f losses will lead to many millions of
dollars per year of wasted power. The klystron group at
SLAC, working with Calabazas Creek Research (CCR), is
developing a gridded, sheet beam klystron. This new
klystron design avoids the CV2 losses of cathode
pulsing because its cathode is not pulsed - it remains at
a constant high voltage. Instead, the grid voltage is
pulsed over a much smaller (6 kV) voltage range. This
paper will describe DTI's progress in development of
the electronics required to drive this new klystron,
including a 500 kV multiplier power supply and grid
modulator, a multi-concentric high voltage cable,
which also acts as the pulse forming line, and an
advanced, reentrant cable connection to the klystron
itself. This design allows the klystron to be located
adjacent to the beamline, and separated from the power
electronics, improving RF efficiency, maintainability,
and overall reliability.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
80-815 - RF Power Supply System of Industry
Iradiation Facility
Alexander Alekseevich Zavadtsev, Valery Timofeevich
Gavich, Oleg Kolosov, Dmitry Alexandrovich
Zavadtsev (Introscan, Moscow), Andrey Krasnov,
Nicolay Sobenin (MEPhI, Moscow)
Irradiation facility is intended for fruit disinfestations.
In particular two 9 MeV 5 kW electron beams are
needed for two side irradiation of oranges at output 30
MT/h and depth dose 150 Gy. Irradiation facility is
based on two identical standing wave accelerators fed
from one 2856 MHz 5 MW klystron. RF power supply
includes master generator, preamplifier, klystron,
waveguide bridge, three 70 dB directional couplers,
two automatic frequency adjustment (AFA) units with
phase detectors and water system, united in two
independent feedback circuits for frequency control: 1)
master generator, amplifier, klystron, waveguide
bridge, 70 dB directional coupler 1, accelerator 1 and
AFA1; 2) 70 dB directional coupler 2, accelerator 2,
AFA2 and water system. Phase detector of AFA1
compares the phases of signal from klystron and signal
from accelerator 1. If accelerator 1 is detuned, AFA1
gives command to the master generator to change
frequency. Control regimes of RF power supply system
including automatic control stability were calculated.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
81-900 - 34 Ghz, 45 Mw Pulsed Magnicon: First
Results
Oleg A. Nezhevenko, Michael A. LaPointe, Vyacheslav
P. Yakovlev (Omega-P, Inc., New Haven, Connecticut),
Jay L. Hirshfield (Omega-P, Inc., New Haven,
Connecticut; Yale University, New Haven, CT)
A high efficiency, high power magnicon at 34.272
GHz has been designed and built as a microwave
source to develop RF technology for a future multiTeV electron-positron linear collider. To develop this
technology, this new RF source is being perfected for
necessary tests of accelerating structures, RF pulse
compressors, RF components, and to determine limits
of breakdown and metal fatigue. After preliminary RF
conditioning of only about 200000 pulses, the
magnicon produced an output power of 10.5 MW in
0.25 microsecond pulses, with a gain of 54 dB. Slotted line
measurements
confirmed
that
the
output
was
monochromatic to within a margin of at least 30 dB.
US Department of Energy, Division of High Energy Physics
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
82-903 - High Power Magnicons at Decimeter
Wavelength for Muon and Electron-Positron Colliders
Oleg A. Nezhevenko, Vyacheslav P. Yakovlev (Omega-P,
Inc., New Haven, Connecticut), Jay L. Hirshfield (Omega-P,
Inc., New Haven, Connecticut; Yale University, New Haven,
CT)
The CLIC drive linac requires pulsed RF amplifiers with a
power of 50 MW at 937 MHz. In turn the muon collider
requires 100 MW, 800 MHz RF amplifiers for the final
stages of acceleration. In this paper conceptual designs of
magnicons for these applications are presented. In addition
to the typical magnicon advantages in power and efficiency,
the designs offers substantially shorter tube length compared
to either single- or multiple-beam klystrons.
US Department of Energy, Division of High Energy Physics
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
83-904 - Inductive Output Tubes for Particle
Accelerators
Heinz Peter Bohlen (CPI, Palo Alto, California), Ed Davies,
Paul Krzeminski, Yanxia Li, Robert Tornoe (CPI/EIMAC,
San Carlos, California)
The Inductive Output Tube (IOT) is not widely used as an
RF power source in particle accelerators yet, but this is
about to change rapidly. One reason for this change is the
IOT's "coming of age": almost twenty years of successful
operation in television transmitters have lead to high
refinement of IOT technology and proven reliability. The
other reason is the fitness of the IOT to especially meet
accelerator requirements: high efficiency, no need for power
back-off to achieve fast feed-back regulation, and the
possibility to pulse the RF without using a high-voltage
modulator. Two classes of IOTs are available so far for
application in particle accelerators. One of them consists of
UHF external-cavity devices, frequency-tunable and
producing output power levels up to 80 kW CW. The second
class has been developed only recently. These are L-band
IOTs with internal output cavities for 1.3 and 1.5 GHz,
respectively, featuring output power levels between 15 and
30 kW CW. Extensive computer simulations have lead to
the conclusion that even higher-power IOTs, such as a 300
kW peak-power, long-pulse L-band tube, are feasible.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
84-970 - RF Supply Systems for Technological
Accelerators
Yuriy D. Tur, Vladimir Beloglazov, Anatoly Nikolayevich
Dovbnya, Leonid Dovbush, Anatoliy Khudyakov, Alexander
Kosoy, Tatyana Nikitina, Sergey Shkirida (NSC/KIPT,
Kharkov)
In accordance with the program of design and manufacture
of industrial electron linacs with high average beam power,
in particular for medical radioisotopes production, we have
carried on research and development on RF-systems,
which is aimed at RF supply of an accelerating system
and electron bunch forming elements of the injector.
Powerful S-band RF-stations have to provide a pulse
power not less then 10-12 MW with a pulse length of
4-5 &#61549;s and repetition rate of 300-400 pps at the
entrance of each accelerating section. Six versions of
the RF power supply system were designed,
constructed and installed; their parameters were
measured and optimized. In particular the testing
results of high power supply stations have shown, that
the long, reliable operation is observed for levels of
pulse output power not less than 12 MW, average
output power not less than 18 kW (400 pps) and 13.5
kW (300 pps), full efficiency of the modulators not less
than 70 % and full efficiency of high-frequency
stations not less than 22 %. The investigations during
long time operation have shown that RF power supply
systems are the very suitable for the use in the high
power accelerator complex. The description of the
design and testing results of the high power RF-station
main components such as HV-modulators, klystrons,
exciting systems and RF power transmission line are
given in this report.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
85-1055 - Multimoded RF Systems for Future
Linear Colliders
Sami G. Tantawi (SLAC/ARDA, Menlo Park,
California), David Schultz (SLAC, Menlo Park,
California), Valery Dolgashev, Christopher Dennis
Nantista (SLAC/ARDB, Menlo Park, California), Jose
Chan (SLAC/NLC, Menlo Park, California)
We have produced 400 ns rf pulses of greater than 500
MW at 11.424 GHz with an rf system designed to
demonstrate technology capable of powering a TeV
scale electron-positron linear collider . Power is
produced by four 50 MW X-band klystrons run off a
common 400 kV solid-state modulator. We present the
layout of our system, which includes a dual-moded
transmission waveguide system and a dual-moded
resonant-line (SLED-II) pulse compression system.
Dual-moding of the transmission lines allow power to
be directed through a pulse compression path or a
bypass path; dual-moding in the pulse compressor
allows the delay lines to be about half as long as they
otherwise would need to be. The modes carried by the
transfer lines are controlled by the rf phases of the
different klystrons. The modes in the delay lines are
controlled by a set of mode converters at the input and
the end of each delay line. We also present data on the
processing and operation of this system, which is
setting high-power records in pulsed rf.
This work is funded by the US Department of Energy
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
86-1231 - IOT based 300 kW RF Amplifiers for the
Diamond Light Source
Juergen Alex (Thales Broadcast & Multimedia AG, Turgi)
All currently operating synchrotron light sources use
klystron amplifiers to generate the RF power for the
accelerator cavities. In TV broadcasting systems on the
other hand, Inductive Output Tubes (IOT)are replacing the
classical klystron based systems in all new high power UHF
transmitters. The Diamond Light Source will be the first
synchrotron to be operated using IOTs. For each
accelerating cavity a total of four IOTs will be combined
with a waveguide combiner to achieve the RF power
requirement of 300 kW at 500 MHz. All IOTs will be
supplied from a common crowbarless high voltage power
supply. Three such systems will be installed starting in
October 2004. This paper gives an overview of the design of
the amplifiers, including the first test results from the
factory commissioning.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
87-1273 - Development of a L-band Multi-beam Klystron
for DESY
Yano Atsunori (KEK, Ibaraki)
A high-power klystron for the TESLA linear collider and
TESLA XFEL has been under development at Toshiba
Electron Tube & Device Co., Ltd. (TETD) in collaboration
with KEK. The TESLA requires pulusd klystrons capable of
10MW output power at 1300MHz wtih 1.5 ms pulse length
and a repetition rate of 10 pps.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
88-1278 - Multipacting in Crossed RF Fields near Cavity
Equator
Valery D. Shemelin (Cornell University, Ithaca, New York)
Electric and magnetic fields near the cavity equator are
presented in a form of expansions up to the third power of
coordinates. Comparisons with numerical calculations made
with the SLANS code for the TESLA and other cavity cells,
as well as with the analytical solution for a spherical cavity
are done. These fields are used for solution of equations of
motion. It appears that for description of motion, the only
main terms of the expansion are essential, but the value of
coefficients for the electric field components depend on
details of magnetic field behavior on the boundary.
Equations of motion are solved for electrons moving in
crossed RF fields near the cavity equator. Based on the
analysis of these equations, general features of this kind of
multipacting are obtained. Results are compared with
simulations and experimental data. The "experimental"
formulas for multipacting zones are explained and their
dependence on the cavity geometries is shown. Developed
approach allows evaluation of multipacting in a cavity
without simulations but after an analysis of fields in the
equatorial region. The fields can be computed by any code
used for cavity calculation.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
89-1324 - Confinement of Finite Sized Bunched
Beams and Its Application to PPM Klystrons
Mark Hess, Chiping Chen (MIT/PSFC, Cambridge,
Massachusetts)
A confinement criterion for a finite sized azimuthally
symmetric relativistic bunched electron beam
propagating through a perfectly conducting cylindrical
pipe with a slight off-axis displacement while in the
presence of either a uniform or periodic solenoidal field
is studied. We compute the center-of-mass force on
each off-axis beam bunch due to the induced surface
charges on the pipe using a Green's function technique.
By analyzing the center-of-mass dynamics of each
bunch due to magnetic focusing and its interaction with
the pipe, a space-charge limit for beam confinement is
derived. A comparison is made between the theory and
several high-current periodic permanent magnet (PPM)
klystron experiments, which are prototypes of the
klystrons utilized in the Next Linear Collider.
This work is supported by the Department of Energy
and the Air Force Office of Scientific Research
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
90-1385 - Large Scale Production of 805-MHz
Pulsed Klystrons for SNS
Stephan Lenci, Edward Eisen (CPI, Palo Alto,
California)
The Spallation Neutron Source (SNS) is an acceleratorbased neutron source being built in Oak Ridge,
Tennessee, by the U.S. Department of Energy. The
SNS will provide the most intense pulsed neutron
beams in the world for scientific research and industrial
development. CPI is supporting the effort by providing
81 pulsed klystrons for the super-conducting portion of
the accelerator. The primary output power
requirements are 550 kW peak, 49.5 kW average at 805
MHz, with an electron beam-to-rf conversion
efficiency of 65% and an rf gain of 50 dB. Through
January 2004, 47 units have been factory-tested.
Performance
specifications,
computer
model
predictions, operating results, and production statistics
will be presented.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
91-1395 - Quasi-optic RF Power Transmission Line
from a FEM Oscaillator
Alim Kaminsky, Artem Elzhov, E.A. Perelstein, Sergey
Sedykh, Alexey Sidorov (JINR, Dubna, Moscow
Region), Naum Ginzburg, Sergey Kuzikov, Nikolay
Peskov, Mikhail Petelin, Alexander Sergeev, Nikolay
Zaitsev (IAP/RAS, Nizhny Novgorod), Anatoly Sergeev
(JINR/
Experimental investigation of a copper resonator
lifetime under multiple action of 30 GHz power pulses
is now carried out by the collaboration of CLIC team
(CERN), FEM group of JINR (Dubna) and IAP RAS
(Nizhny Novgorod). A quasi-optic two-mirror
transmission line is used between the FEM oscillator
and test cavity. An oversized FEM output waveguide
based on the wavebeam transformation (Talbot effect)
provides the optimal transverse distribution of the
radiation, eliminates the output window breakdown and
decrease the influence of the reflected wave on the FEM
oscillator regime.
This work is supported by grants &#8470;&#8470; 03-0216530, 02-02-17438 of Russian Foundation for Basic
Research and by INTAS grant &#8470; 03-51-5319
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
92-1440 - Design of a Novel RF CavityTuner for Minimal
Vibration
Jim Rank, Ilan Ben-Zvi (BNL, Upton, Long Island, New
York)
To avoid energy loss in an RF cavity resulting from
acoustical noise and vibration demands a support structure
that is capable of stiffening the cavity, yet allows the
necessary flexibility for proper tuning. A novel design for a
cavity tuner, discussed herein, has the added feature of
boosting in all degrees of freedom the natural frequencies of
the structure by several times.
Research performed under the auspices of the Department of
Energy, Department of Defense
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
93-1445 - Test Results for a 10-MW, L-band, Multiplebeam Klystron for TESLA
Edward Wright, Adam Balkcum, Heinz Peter Bohlen (CPI,
Palo Alto, California)
The VKL-8301 high-efficiency, multiple-beam klystron
(MBK), has been developed for the DESY Tera Electron
volt Superconducting Linear Accelerator (TESLA) in
Hamburg, Germany. The first prototype is built and will be
tested in March of 2004. The prototype has been designed
for long-life operation by utilizing the benefits inherent in
higher-order mode (HM) MBKs. The primary benefit of
HM-MBKs is their ability to widely separate individual
cathodes. One of the major obstacles to the success of this
approach is the design of the off-axis electron beam
focusing system, particularly when confined-flow focusing
is desired. We will show simulated and measured data
which demonstrates a solution to this problem. High power
test results will also be shown.
This work supported by Deutsches Elektronen-Synchrotron
DESY
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
94-1458 - Test Results for the New 201.25 MHz Tetrode
Power Amplifier at LANSCE
John T.M. Lyles (LANL/LANSCE, Los Alamos, New Mexico)
A new RF amplifier has been constructed for use as the
intermediate power amplifier stage for the 201.25 MHz
Alvarez DTL at LANSCE. It is part of a larger upgrade to
replace the entire RF plant with a new generation of
components. The new RF power system under development
will enable increased peak power with higher duty factor.
The first tank requires up to 400 kW of RF power. This can
be satisfied using the TH781 tetrode in a THALES cavity
amplifier. The same stage will be also used to drive a
TH628 Diacrode? final power amplifier for each of the three
remaining DTL tanks. In this application, it will only be
required to deliver approximately 150 kW of peak power.
Details of the system design, layout for DTL 1, and test
results will be presented.
Work supported by the United States Department of
Energy under contract W-7405-ENG-36
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
95-1702 - High Power Test and Pulse Shaping of
Long Pulse MBK Klystron Microwave System for
10MeV LINAC for Food Irradiation
Purushottam Shrivastava (CAT, Indore (M.P.))
At Centre for Advanced Technology, CAT, Indore,
India, a 10MeV electron LINAC with beam power over
10kW is under development for food irradiation
applications. A microwave system based on 6MW peak
25kW average power multibeam klystron has been
designed, developed and tested at CAT for energizing
the 10MeV LINAC. The klystron needs about 50-55kV
beam voltage with beam current of 270 Amp. A line
type pulse modulator has been developed inhouse to
produce 55kV, 270 Amp pulses in duration of 12.5
microseconds and a PRR of 300 Hz. The microwave
system operates in two modes, the first mode has full
duration of 12.5 microseconds but PRR limited to 300
Hz as per the average power limits whereas in second
mode the pulse width is decreased to half and PRR is
increased in accordance. The complete system has been
installed in the equipment bay of the LINAC. Present
paper gives details of the high power tests done on the
multibeam klystron, MBK, as well as the pulse shaping
efforts to bring the pulse characteristics within the
specified specifications.
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
96-1722 - Space-charge-limited Magnetron
Injection Guns for Gyroklystrons
Wes Lawson (Maryland University, College Park,
Maryland)
We present the results of several space-charge-limited
(SCL) magnetron injection gun (MIG) designs which
are intended for use with a 500 kV, 500 A gyroklystron
with accelerator applications. The design performances
are compared to that of a temperature-limited (TL) gun
that was constructed for the same application. The SCL
designs yield similar values for beam quality, namely
an axial velocity spread under 3% for an average
perpendicular-to-parallel velocity ratio of 1.5. The peak
electric fields and the cathode loadings of the SCL
designs are somewhat higher than for the TL design.
Three designs are described in this paper. In the first
design the space-charge limit is achieved by recessing
the emitter into the cathode. The other two designs
have control electrodes to which a voltage can be
applied to change the beam current independently of
the beam voltage. One of these designs can accept a
bias sufficiently high to cut off the current completely,
so that a DC power supply with pulsed grid operation
is possible. Details of all designs as well as a
discussion of the advantages and disadvantages of the
SCL designs as compared to the TL design will be
given.
Work supported by th US Department of Energy, HighEnergy Physics Branch
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
97-1763 - Power Conversion Efficiency Enhancement for
Indus-2 Solid State Power Amplifier
Akhilesh Jain, Pundalik Rama Hannurkar, Deepak Sharma
(CAT, Indore (M.P.))
RF amplifier with solid state devices is an integral part of
RF system. Four Solid State Power Amplifier (SSPA) (30
dB gain) have been designed for driving 64KWatt Klystron
in Indus-2 SRS. Efficiency of amplifiers was 12% due to
simple class A matching circuit. Hence an inter-stage waveshaping network was designed and original amplifier design
was modified to give measured efficiency of 42%. Ideal
efficiency of 50% in class A is never achieved in practice
due to several practical limitations. Designed waveshaping
network was placed between two amplifier stages. This
network eliminates odd harmonics and harness even
harmonics to boost fundamental component of RF current
flowing through drain. Further RF signal presented to input
of second stage, get waveshaped using output circuit of first
stage in the form of half Positive sinusoids. This technique
saves RF power in negative half of input signal to second
stage. Negative half sinusoid does not contribute to
amplification in any of the A, B or C class of operation.
Load and source were decided based on fundamental and
harmonic load line calculation. All these exercise has
boosted efficiency to 42% from original design efficiency.
Centre for Advanced Technology (CAT) Indore INDIA
Type of presentation requested: Poster
Classification: [T08] RF Power Sources
98-339 - Permanent Magnet Generating High Septum
Magnetic Field and its Deterioration by Radiation
Tadamichi Kawakubo, Eiji Nakamura (KEK, Ibaraki),
Masaaki Aoki, Tsuyoshi Hisamura, Ken Makita, Eiji
Sugiyama (SSMC, Mishima-gun, Osaka)
Conventional high field septum magnet is fed by DC current
or pulse current. In the case of DC, the problem of coil
support is not very important, but the cooling of the coil is
serious problem. While, in the case of pulse, the problem of
support is much important than that of cooling. However, if
the septum magnet is made of permanent magnet, those
problems are dissolved. And the cost for electricity and
cooling water can be exceedingly decreased. Therefore, we
made the model septum magnet which has 1/4 scale of the
real size and generates 1[T]. The magnetic field distribution
in the gap is reported. When this permanent magnet is set in
an accelerator, the deterioration of the permanent magnet by
radiation will be serious problem. We also report the
dependence of the magnetic fields generated by permanent
magnet samples on accumulated radiation by various types
of radiation source.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
99-436 - Magnets for the CANDLE Booster
Synchrotron, Design and Prototyping
Vitali Khachatryan, Yuri Lawrent Martirosyan
(CANDLE, Yerevan)
CANDLE booster synchrotron magnetic lattice
contains 48 dipoles of H-shape. Detailed magnetic and
mechanical design of those magnets is performed
within the framework of the project. In this report, the
design considerations of the dipole magnet, including
the magnetic field simulation is presented. The main
features of the fabricated first prototype dipole magnet
are discussed.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
100-498 - The Storage Ring Magnets of the
Australian Synchrotron
Erhard Huttel (FZK-ISS-ANKA, Karlsruhe), Alan
Jackson, Gregory Scott LeBlanc (ASP, Melbourne),
Jack Tanabe (SLAC, Menlo Park, California)
A 3 GeV Synchrotron Radiation Source is being built
up in Melbourne, Australia. The storage ring has a
circumference of 216 m and has a 14 fold DBA
structure. For the storage ring the following magnets
are required: 28 gradient dipoles, with B = 1.3 T,
B&#8217; = 3.35 T/m, 56 quadrupoles with a gradient
of B&#8217; = 18 T/m, 28 quadrupoles with a
gradient of 9 T/m, 56 sextupoles with d2B/dr2 = 320
T/m2 and 42 with 150 T/m2. The design of pole faces
was done by scaling the SPEAR III pole face to the
required gap and bore of the ASP storage ring magnets.
The sextupoles will be equipped with coils for
horizontal and vertical correction and for a skew
quadrupole. The design of the magnets and the
calculated magnetic properties will be presented.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
101-617 - A General Method for 2d Magnet Pole
Design
Zeus Mart&#237;, Josep Campmany, Miquel Traveria
(LLS, Bellaterra (Cerdanyola del Vallès))
Accurate conventional combined magnets working in
saturation are currently required to fulfil the increasing
demands on low emittance accelerators with long
straight sections required by the newest Synchrotron
Light Sources. This fact yields stringent requirements
on
pole
profile
design,
manufacture
and
characterization. The aim of this poster is to present a
general method for designing two-dimensional pole
profiles. To this end, we have set up a procedure with
which to select an optimum pole profile in 2D without
the constraint of relying on a set of initial assumptions,
not only a particular set of initial parameters but even a
particular pole profile model. Moreover, we have
developed a group of codes that can be compiled and
run on MS-DOS or UNIX which use POISSON or
OPERA-2d codes. This procedure also includes the
evaluation of the sensitivity of the final pole profile to
geometrical and current intensity errors for tolerance
estimation, a big requirement in this context. In order
to test the feasibility of this method, we have applied it
to the case of the 1.2 T combined magnet of the new
synchrotron to be built nearby Barcelona.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
102-738 - Bending Magnets for the SAGA Storage Ring:
Manufactoring and Magnetic Measurements
Sergey Sinyatkin, Igor Churkin, Oleg Kiselev, Vladimir
Korchuganov, Alexander Ogurtsov, Alexander
Philipchenko, Leonid Schegolev, Karl Schreiner, Andrey
Steshov (BINP, Novosibirsk), Masanori Kuroda, Yoshio
Tsuchida (Saga Synchrotron Light Source, Saga Cit
The paper describes the design, the manufacture and the
magnetic measurement of the dipole bending magnets (BM)
for SR Source storage ring (prefecture SAGA, Japan)
carried out in BINP, Novosibirsk, Russia. The requirement
was to create the laminated C-shape BMs with the 3.2 m
radius and parallel edges. The magnetic field homogeneity
must be not worth than ±2?10-4 inside the working area: H
= 30+40mm and V = ±20mm at 0.26T (250 MeV), and H =
± 28mm and V = ±20mm at 1.46 T (1.4GeV). The BMs
were designed on the basis of the 2-D 3-D modeling taking
into account the laminated core. The BMs yokes were
produced with the help of the technology of the high
temperature gluing. The computer simulations are in a good
agreement with the magnetic measurements. The main
parameters of the magnetic fields satisfy to the requirements
and are presented. The features of the design, manufacturing
and precise magnetic measurements of SAGA BMs are
discussed.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
103-824 - The Modified DAFNE Wigglers
Susanna Guiducci, Sergio Bertolucci, Maurizio Incurvati,
Miro Preger, Pantaleo Raimondi, Claudio Sanelli,
Francesco Sgamma (INFN/LNF, Frascati (Roma))
Modifications to the pole shape of a spare wiggler have been
tested to increase the width of the good field region, with the
aim of reducing the effect of nonlinearities affecting the
dynamic aperture and the beam-beam interaction. Additional
plates realized with the same material of the pole have been
machined in several shapes and glued on the poles. Accurate
measurements of the vertical field component on the
horizontal symmetry plane of the magnet have been
performed to find the best profile. The particle motion inside
the measured field has been simulated to minimize the field
integral on the trajectory, to determine the wiggler transfer
matrix and to estimate the amount of non linear
contributions. All wigglers in the collider have been
modified to the optimized pole shape. Measurements with
beam performed with the modified wigglers show a
significant reduction of nonlinearities.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
104-832 - Magnetic Field Correction of the Bending
Magnets of the 1.5 GeV HDSM
Frank Hagenbuck, Peter Jennewein, Karl-Heinz Kaiser
(IKP, Mainz)
Beam dynamics of the Harmonic Double Sided Microtron
(HDSM), the fourth stage of MAMI, require a very precise
magnetic field in the inhomogeneous bending magnets. By
measuring the vertical field component By in and on
both sides of the midplane, the complete set of field
components Bx, By, Bz was determined in the whole
gap. Starting from this the asymmetric pole surface
current distribution necessary to correct both
symmetric and antisymmetric field errors was
calculated. However, tracking calculations showed that
the influence of skewed field components on the beam
deflection are negligible, so that symmetric field
corrections are sufficient. Nevertheless, in order to
demonstrate the functioning, a set of asymmetric
correction coils was built and successfully tested. The
symmetric coils are designed to reduce field errors
below 2*10^-4. Deflection errors in the fringe field
region near the magnet corners, which cannot be
corrected by surface currents, will be compensated by
vertical iron shims in combination with small dipoles
on each beam pipe.
Work supported by Deutsche Forschungsgemeinschaft
(SFB 443)
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
105-875 - The Design of the Special Magnets for
PIMMS/TERA
Luc Sermeus, Jan Borburgh, Massimo Crescenti, Tony
Fowler, Michael Hourican, Klaus Dieter Metzmacher
(CERN, Geneva)
In the framework of a collaboration agreement with the
TERA Foundation CERN provided the design,
drawings and engineering specifications for 2 kickers,
1 chopper and 3 bumper magnets as well as 3 magnetic
and 2 electrostatic septa, power supplies for the
electrostatic septa, kickers and bumpers including
control electronics for the PIMMS/TERA proton and
carbon ion medical synchrotron. The first application
will be in the Italian National Centre for Hadron
Therapy, to be constructed in Pavia. The main features
of the devices are described along with the strategic
design choices, directed by the demand for very high
reliability and minimum maintenance.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
106-894 - Magnetic Quadrupole Lenses for the
IFUSP Microtron
Tiago Fiorini Silva, Mauricio Lima Lopes, Alexandre
Almeida Malafronte, Marcos Martins, Paulo Beolchi
Rios, Jiro Takahashi (USP/LAL, Bairro Butantan)
The Instituto de Física da Universidade de São Paulo
(IFUSP) is building a two-stage 31 MeV continuous
wave (cw) racetrack microtron. In this work, we
describe the design of the magnetic quadrupole lenses
for the IFUSP microtron. The design consists of a
laminar structure divided in four equal pieces. Because
each piece corresponds to an individual pole, it eases
the assembling of the coils and the installation of the
quadrupole on the beam transport line without breaking
the vacuum. Due to the fact that the quadrupole is
laminated along the longitudinal axis, it is possible to
change the length of a given lens by adding or
subtracting foils. We also present the magnetic field
distribution calculated using the POISSON code. A
prototype presented good mechanical rigidity and thermal
performance, showing that a refrigeration system is not
necessary. The magnetic measurements show that the field
distribution within the region of interest agrees with the
POISSON simulation.
CNPq, FAPESP
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
107-902 - Design of the End Magnets for the IFUSP
Main Microtron
Mauricio Lima Lopes, Alexandre Almeida Malafronte,
Marcos Martins, Jiro Takahashi (USP/LAL, Bairro
Butantan), Karl-Heinz Kaiser (IKP, Mainz)
The Instituto de Física da Universidade de São Paulo
(IFUSP) is building a two-stage 31 MeV continuous wave
(cw) racetrack microtron. In this work we describe the
characteristics of the end magnets for the IFUSP main
microtron. The magnets are part of the main acceleration
stage, which raises the energy from 4.9 to 31 MeV. We are
studying the possibility of increasing the energy up to 38
MeV, so the magnets should have approximately 2x1 m2
region of useful field. The dipoles have a 0.1410 T magnetic
field and 1 part in 1000 homogeneity without correcting
devices. Using a 2D magnetic field code (FEMM), we
illustrate the use of homogenizing gaps with different forms
and non parallel pole faces to achieve the necessary
homogeneity. The use of clamps to produce reverse fields
to reduce the vertical defocusing strength on the beam is
also described. In order to calculate the beam trajectories
and to evaluate the magnetic field homogeneity within the
useful region, a 3D magnetic field software (TOSCA) was
used.
CNPq, FAPESP
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
108-1012 - Study of Electrical Steel Magnetic Properties
for Fast Cycling Magnets of SIS100 and SIS300 Rings
Igor Bogdanov, Sergey Kozub, Petr Shcherbakov, Leonid
Tkachenko (IHEP Protvino, Protvino, Moscow Region),
Egbert Fischer, F. Klos, Gebhard Moritz, Carsten Muehle
(GSI, Darmstadt)
The operation conditions of yoke steels in superconducting
magnets of the SIS100 and SIS300 are at 4.2 K and unipolar
cycles with high magnetic induction. The results of
measurements of different classes of electrical steels, both
isotropic and anisotropic, in the operating conditions of
superconducting dipoles are presented. The measurements
are carried out on ring samples in quasistatic mode.
Dependence of B(H) as well as values of Hc and hysteresis
losses in bipolar and unipolar cycles are determined from
hysteresis loops at different temperatures. The anisotropy of
steels is measured at room temperature on the strip samples,
cut along the rolling direction and across one. The
comparison of results on ring and strip samples is carried
out. The results of calculations of hysteresis and eddy
current losses in iron yoke of fast-cycling dipole for the
SIS300 are presented. The recommendations on choice of
grade steels for fast cycle superconducting magnets are
given.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
109-1028 - Super Strong Permanent Magnet
Quadrupole for a Linear Collider Final Focus
Takanori Mihara, Yoshihisa Iwashita (ICR Kyoto,
Kyoto), Antokhin Evgeny, Masayuki Kumada (NIRS,
Chiba-shi), Cherrill M. Spencer (SLAC, Menlo Park,
California), Eiji Sugiyama (SSMC, Mishima-gun,
Osaka)
A super strong magnet, which utilizes permanent
magnet material and saturated iron, is considered as a
candidate for the final focus quadrupole in a linear
collider beamline. This modified Halbach magnet
configuration can have a higher magnetic field gradient
than a normal permanent magnet quadrupole (PMQ) or
electromagnet. There are some issues to be solved if a
PMQ is to be used as a final focus quadrupole: the
variation of its strength with temperature and the need
for the field strength to be deliberately changed. One
can use special temperature compensation material to
improve the temperature dependence with just a small
decrease in field gradient compared to a magnet
without temperature compensation. The required field
variability can be obtained by slicing the magnet into
pieces along the beamline direction and rotating these
slices. Results of performance measurements on the
PMQ with variable strength will be reported including
the realization of the temperature compensation
technique.
This research was partially supported by the Ministry
of Education, Science, Sports and Culture, Grant-inAid for Scientific Research (A) 14204023, 2002
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
110-1094 - Stretched Wire Flip Coil System for
Magnetic Field Measurements
Dong Eon Kim, Chin Wha Chung, Hong Sik Han,
Young Gyu Jung, Hong Gi Lee, Wol Woo Lee, KiHyeon Park, Hyung Suk Suh (PAL, Pohang)
A flip-coil system using a stretched wire measuring the
magnetic field properties of accelerator magnets is
described. This system is similar to the conventional
rotating coil system except that the stretched wires are
used instead of wires wound on the machined surface.
This system has advantage of simple fabrication and
flexible operation so that different length and bore
magnets can be easily measured using the same system.
The system also has two loop coils to buck the
dominant fundamental field so as to increase the
measurement accuracy. This kind of system has issues
related to the reproducibility, accuracy of the measured
results. The system is evaluated to verify its
performances and its results were discussed. The
analyzing methods and various efforts to keep the
system in high accuracy are presented. Measurement
results with this loop coil system were compared with
that of the other system.
This work is supported by POSCO, MOST of Korea
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
111-1249 - Application of Finite Volume Integral
Approach to Computing of 3D Magnetic Fields Created
by Distributed Iron-dominated Electromagnet
Structures
Oleg Chubar, Chamseddine Benabderrahmane, Olivier
Marcouill&#233;, Fabrice Marteau (SOLEIL, Gif-surYvette), Joel Chavanne, Pascal Elleaume (ESRF, Grenoble)
Iron-dominated electromagnet structures are traditionally
considered as a domain of applications of the Finite-Element
Method (FEM). FEM computer codes provide high accuracy
for "close circuit" type geometries, however they are much
less efficient for distributed geometries consisting of many
spatially separated magnets interacting with each other.
Examples of such geometries related to particle accelerators
are insertion devices, quadrupole and sextupole magnets
located close to each other, magnets with combined
functions. Application of the finite volume integral approach
implemented in the Radia 3D magnetostatics code to solving
such geometries is described. In this approach, space around
individual magnets does not require any meshing. An
adaptive segmentation of iron parts, with the segmenting
planes being roughly perpendicular or parallel to the
expected directions of magnetic flux lines, minimizes
dramatically the necessary CPU and memory resources. If a
geometry is, nevertheless, too big for its complete
interaction matrix to fit into memory, a special scheme of
relaxation "by parts" can be applied. The results of
calculations made for the SOLEIL electromagnet undulator
HU256 will be presented.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
112-1308 - Magnetic Field Measurement of Quadrupole
Magnets for S-LSR
Takeshi Takeuchi, Koji Noda, Shinji Shibuya (NIRS, Chibashi), Hicham Fadil, Masahiro Ikegami, Akira Noda,
Toshiyuki Shirai, Hiromu Tongu (ICR Kyoto, Kyoto)
S-LSR is a low energy ion storage/cooler ring. It has 12quadrupole magnets (QM) with a bore radius of 70 mm and
a maximum field gradient of 5 T/m. To suppress and control
a magnetic flux in a fringing field of a bending magnet
(BM), a field clamp with a thickness of 25 mm was installed
in between BM and QM. The distance between the field
clamp and QM is 80 mm. 3D calculation represented that
the QM field is strongly influenced by the field clamp.
Therefore, QMs were designed and optimized in considering
the influence of the field clamp. Magnetic field
measurements were performed by means of a Hall probe and
a long search coil. A magnet field measurement by a Hall
probe was carried out together with the field clamp and BM
for S-LSR. For 12-quadrupole magnets, the measurement by
the long search coil which moves in horizontal direction was
carried out. The results for each measurements will be
discussed.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
113-1470 - Radiation Damage Studies with Hadrons
on Materials and Electronics
James Spencer, Zachary Wolf (SLAC, Menlo Park,
California), James T. Volk (Fermilab, Batavia,
Illinois), Maxwell Chertok, David Pellet (UCD, Davis)
Many materials and electronic devices need to be tested
for the radiation environment expected at the proposed
linear colliders (LC) where the accelerator and
detectors will be subjected to large fluences of hadrons,
electrons and gammas during the life of the facility.
Examples are NdFeB permanent magnets which are
being considered for the damping rings and final focus,
electronic and electro-optical devices which will be
utilized in the detector readout and accelerator control
systems and CCDs required for the vertex detector. The
effects of gammas on a broad range of materials was
presented at NSREC2002 and our understanding of the
current situation concerning rare earth permanent
magnets at PAC2003 where a program was proposed
using neutrons from the McClellan Nuclear Reactor
Center (MNRC) that has a number of areas for
irradiating samples with neutron fluxes up to 4.5E13
n/cm2s. A specialized area allows irradiation with 1
MeV-equivalent neutrons with fluxes of 4.2E10 n/cm2s
while suppressing thermal neutrons and gammas by
large factors. We give our latest results and their
interpretation using this facility.
This work is funded by the U.S. Department of Energy
under contract DE-AC03-76SF00515, DE-AC0276CH03000 and DE-FG02-03ER41280.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
114-1544 - Gradient Field Generation in a Uniform
Gapped Magnet
Yoshihisa Iwashita (ICR Kyoto, Kyoto), Yasushi
Arimoto, Akira Sato (Osaka University, Osaka)
Magnets with gradient field (indexed magnets) usually
have different gap distances with the different entrance
positions. This situation will break a uniformity of the
effective length. Trim coils, which are usually used in
Cyclotron, are not practical to modify a field
distribution when a large gradient is required such as
FFAG. In order to generate a gradient field in a
constant gapped magnet, a novel method with use of
inter-pole is devised. This magnet has not only constant
gap but also smaller fringing field compared with a
conventional one. This technique should widen the
recipe to design a magnet with such a complex
magnetic field.
Type of presentation requested: Poster
Classification: [T09] Room-Temperature Magnets
115-243 - The 5 T Superconducting Undulator for
the LHC Synchrotron Radiation Profile Monitor
Remo Maccaferri, Massimo Facchini, Roland Jung,
Davide Tommasini, Walter Venturini Delsolaro
(CERN, Geneva)
A Synchrotron Radiation Profile Monitor will be used
in the LHC to measure the beam profiles from the
injection energy of 450 GeV to the nominal energy of 7
TeV. The radiation will be provided by a sequence of
two separate magnets: a two-periods 5 T
superconducting undulator and the beam separation dipole
D3. After a short description of the profile monitor layout,
the paper reviews the electromagnetic and mechanical
design of the undulator, and reports on the fabrication and
cold test results of a first half period prototype.Finally, for
the LHC operation with lead ion beams,a proposal for a
monitor sensitivity upgrade by using a 12 T.
superconducting undulator is presented and discussed.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
116-292 - Performance of the Superconducting Matching
Quadrupoles for the LHC Insertions
Nuria Catalan-Lasheras, Glyn Kirby, Ranko Ostojic, Juan
Carlos Perez, Herve Prin (CERN, Geneva)
The optics flexibility of the LHC insertions is provided by
the individually powered quadrupoles in the dispersion
suppressors and matching sections. These units comprise
special quadrupole magnets of the MQM and MQY type and
range in length from 5.4 m to 11.4 m. In total, 82 insertion
quadrupoles will be assembled at CERN. In this paper we
present the advance in construction and report on the
performance of the first series built quadrupoles. In
particular, we present the quench performance of the
individual magnets and alignment measurements of the cold
masses, and discuss the field quality trends and possible
implications.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
117-515 - Superconducting Solenoid for VEPP-2000
Collider
Yuri Shatunov (BINP, Novosibirsk)
To create conditions for the round beam option at the
electron-positron collider VEPP-2000, a specific final focus
system with superconducting solenoids have been developed
at Budker Institute. Each solenoid consists of 52 cm main
part with magnetic field up to 13T and a short antisolenoid
with -7T field that has to adjust focusing properties. The
main coil is shared in two sections: internal section is wound
by 1.26 mm niobium-tin wire; external - by 1.24 mm and
0.9 mm niobium-titan wires. Separate power supplies of all
sections provide flexible control of beta-functions in the
Interaction Points at whole energy range of the collider (200
-1000 MeV). The coils are assembled in a common iron
yoke, which is embedded into a liquid helium cryostat. The
cryostat design performs to carry out high vacuum pumping
in the IPs by a surface of the cryostat internal tube, which
has helium temperature and open to machine vacuum
through slits in a cooper liner. This liner is kept under the
liquid hydrogen temperature and has to absorb on the top
energy 100 Watt power of the synchrotron radiation from
bending magnets.
ISTC grant #1928
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
118-607 - The HD Prototype Series: 16 Tesla
Dipoles for Future Colliders
GianLuca Sabbi, Scott Bartlett, Shlomo Caspi, Daniel
Dietderich, Paolo Ferracin, Stephen Gourlay, Ray
Hafalia, Roy Hannaford, Alan Lietzke, Sara Mattafirri,
Alfred McInturff, Mark Nyman, Ronald Scanlan
(LBNL, Berkeley, California)
The Nb3Sn dipole HD1, recently fabricated and tested
at LBNL, pushes the limits of accelerator magnet
technology into the 16 Tesla field range, and opens the
way to a new generation of hadron colliders. Magnets
operating at the highest possible fields are especially
required for machine upgrades, directed toward an
increase of either the beam energy or the luminosity.
While both of these strategies can expand the physics
reach of a collider, the energy route has the advantage
of not requiring major detector upgrades. The LBNL
superconducting magnet program has achieved
progressively higher dipole fields using Nb3Sn in a
variety of coil configurations: cosine-theta (D20, 13.5
T), common coil (RD3b, 14.5 T) and block-coil (HD1,
16 T). This paper will discuss the HD1 results, as well
as the next steps in the HD series. Future prototypes
will introduce a larger bore, accelerator field quality,
and a further increase of the dipole field using
improved conductor and graded coils.
This work was supported under contract DE-AD0376SF00098 by the Director, Office of Energy
Research, Office of High Energy Physics, U.S.
Department of Energy
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
119-619 - Nb3Sn Technology Development for the
LHC Luminosity Upgrade
GianLuca Sabbi, Scott Bartlett, Shlomo Caspi, Daniel
Dietderich, Paolo Ferracin, Stephen Gourlay, Ray
Hafalia, Roy Hannaford, Sara Mattafirri, Alfred
McInturff, Mark Nyman, Ronald Scanlan (LBNL,
Berkeley, California)
The U.S. LHC Accelerator Research Program, a
collaboration of BNL, FNAL and LBNL, is directed
toward the development of advanced magnet
technology for the LHC luminosity upgrade. LBNL
supports this program with a broad effort involving
design studies, Nb3Sn conductor development,
mechanical models, and simple prototypes. The design
studies concentrate on the choice of the optimal coil
geometry and the mechanical support structure. The
conductor development is presently focused on cable
optimization for the different designs. Mechanical
models are used to validate the results of detailed 3D
analysis, and to refine the magnet assembly procedures.
Simple prototypes are designed to investigate thermal,
quench protection and field quality issues using
subscale coils in both dipole and quadrupole
configurations. In this paper, recent highlights from the
R&D program will be presented and discussed.
This work was supported under contract DE-AD0376SF00098 by the Director, Office of Energy Research,
Office of High Energy Physics, U.S. Department of Energy
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
120-698 - Non-destructive Testing of Joints of Bus-bars
Powering LHC Superconducting Magnets, by Using
Gamma Sources
Blazej Skoczen (CERN, Geneva), Jan Kulka (AGH, Cracow)
The main LHC superconducting magnets (dipoles and
quadrupoles) are powered by using Rutherford type cables,
stabilized electrically and thermally with copper profiles.
The portions of cables are connected to each other by a soft
soldering technique (Sn96Ag4) with the overlapping length
corresponding to one pitch of the superconducting strands.
The splice constitutes a ?composite? structure with the
interchanging layers of Sn96Ag4 and NbTi superconductor,
located inside a Cu cage. In order to assure a high level of
reliability (failure probability not exceeding 10^-8) for some
10000 connections in the LHC, a non-destructive technique
of checking the quantity of solder in the joint is planned to
be implemented. The technique is based on a gamma ray
source (241_Am) and the detection is position-sensitive in
the transmission mode. 5 scintillating detectors of gamma
rays are used and their accumulated length corresponds to
the length of the radioactive source (120 mm). The method
can be used in-situ, the equipment being optimized and
portable, with implementation of direct on-line operation
mode. The relevant criteria of acceptance of the splices have
been defined. The first results of application of this
technique will be shown.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
121-775 - Electro-mechanical Aspects of the
Interconnection of the LHC Superconducting Corrector
Magnets
Jean-Philippe TOCK, Davide Bozzini, Franck Laurent,
Stephan Russenschuck, Blazej Skoczen (CERN, Geneva)
In addition to the main 1232 bending dipoles and 474
focusing and defocusing quadrupoles, more than 6800
superconducting corrector magnets are included in the LHC
machine. They are housed in the superfluid helium
enclosures of the main cryomagnets. Among them, the
closed orbit correctors (sextupole and octupole) are
integrated in the main quadrupole helium vessel and they are
powered via an externally routed cryogenic line (line N).
During the assembly, these corrector magnets have to be
connected according to a complex electrical scheme based
on the optical requirements of the LHC machine. Along the
27-km long LHC machine, 440 interconnection boxes are
installed and will allow the powering of the correctors by
means of a 42-wires auxiliary bus-bar cable, of which the
corresponding wires have to be routed to the SSS from the
interconnection box. Stringent requirements in terms of
volume, mechanical resistance, electrical conductance and
insulation, reliability, and respect of the electrical
schematics apply during the assembly and splicing of the
junctions inside the line-N box. The activities and their
sequence, aiming at ensuring the fulfilment of these
requirements are presented. The planned activities
(assembly, ultrasonic welding, general and electrical
inspection, and electrical qualification) and the
interactions between the various intervening teams are
described.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
122-779 - Magnetic Measurement Systems for the
LHC Dipole Assembly Firms
Hubert Reymond, Alessandro Raimondo, Vittorio
Remondino, Adriaan Rijllart (CERN, Geneva)
The LHC lattice superconducting dipole magnets are
actually under construction in three European
industries. Due to the extremely high magnet
performance required for the LHC, these magnets have
to be built with high accuracy during all the steps of
their assembling. In order to detect defects in the
earliest production phases and to ensure the quality of
the magnetic field as specified by the CERN contracts,
dedicated measurement benches have been built and
installed in each industry to validate the magnetic field
quality at two important production stages. This paper
describes the initial requirements and the
implementation of the magnetic measurement systems.
Details on the technical solutions, the present status
and measurement results are presented.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
123-801 - Magnetic Field Tracking Experiments for
LHC
Valeria Granata, Jacques Billan, Frederick Bordry,
Luca Bottura, Pedro Miguel Coutinho Ferreira, Ewald
Effinger, Gunnar Fernqvist, Peter Galbraith, Quentin
King, John Pett, Alessandro Raimondo, Adriaan
Rijllart, Hugues Thiesen (CERN, Geneva)
At the Large Hadron Collider (LHC) at CERN one of
the fundamental requirements during the energy ramp
is that the ratio between the field produced by the
quadrupoles and the field in the dipoles remains
constant in order to minimize the variation of the
betatron tune that could induce particle loss. With a
series of tracking experiments it has been demonstrated
that this ratio can be maintained constant to better than
10-4 throughout the same current ramp as foreseen for
the LHC. A technique has been developed to optimise
the dipole and quadrupole current ramps to obtain the
required ratio of B2/B1. Measurements performed by
modulating the current with a harmonic function (socalled k-modulation) demonstrated that it is possible to
modulate the strength of an individual quadrupole to
determine the magnetic center through beam-based
measurements.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
124-802 - A Strategy for Sampling of the Field
Quality of the LHC Dipoles
Luca Bottura, Stephane David Fartoukh, Valeria
Granata, Ezio Todesco (CERN, Geneva)
We have measured the magnetic field of a considerable
fraction of the superconducting LHC main dipoles, of
the order of 300 in warm conditions and 100 in cold
conditions. All LHC dipoles will be measured in warm
conditions at the manufacturers to steer the production
inside the acceptance limits imposed by beam dynamics.
Using the available data we analysed the distributions of the
main field and higher order field errors in warm and cold
conditions, as well as the distribution of the warm-to-cold
correlation. Based on this analysis we predict the minimum
number of magnets that should be measured in cold
conditions in order to guarantee that (1) the production is
controlled within the specified limits (2) the field is known
to a sufficient level for a sound installation and (3) the
uncertainty on the knowledge of the magnetic field of the
LHC dipoles is small enough for the commissioning of the
accelerator and to insure operation of the machine in any
condition, including higher energy. The main outcome of
this analysis is that cold measurements on a fraction of the
order of one third of the total production, i.e. approximately
400 dipoles, will be sufficient to achieve the above
objectives.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
125-804 - A Scaling Law for Predicting Snap-back in
Superconducting Accelerator Magnets
Luca Bottura, Tatiana Pieloni, Stephane Sanfilippo (CERN,
Geneva), Giorgio Ambrosio, Pierre Bauer (Fermilab,
Batavia, Illinois), Markus Haverkamp (Twente University,
Enschede)
The decay of the sextupole component in the bending
dipoles during injection and the subsequent snap-back at
particle acceleration are issues of common concern, albeit at
different levels of criticality, for all superconducting
colliders built (Tevatron, HERA, RHIC) or in construction
(LHC) to date. The main difficulty is the correction of the
relatively large and fast sextupole change during snap-back.
Motivated by the above considerations, we have conducted
an extended study of sextupole snap-back on two different
magnet families, the Tevatron and the LHC bending dipoles,
using the same measurement method. We show in this paper
that it is possible to generalise all the results obtained by
using a simple, exponential scaling law. Furthermore, we
show that for magnets of the same family the parameters of
the scaling law correlate linearly. This finding could be
exploited during accelerator operation to produce accurate
forecast of the snap-back correction based solely on beambased measurements.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
126-842 - Field Quality and Hysteresis of LHC
Superconducting Corrector Magnets
Robert Wolf (CERN, Geneva)
The Large Hadron Collider (LHC) will use some 6400
superconducting corrector magnets. There are 19 corrector
types. These are assembled 14 different types of magnets of
which 4 are nested. They are being manufactured by 4 firms
in Europe and 3 in India. The magnetic field quality is
measured at room temperature by 12 magnetic measurement
benches employed by the corrector manufacturers. CERN
performs magnetic measurement at 4.2K and at 1.9K on a
small subset of corrector magnets. The paper discusses the
correlation between the warm and cold field measurements.
The field quality is compared to the magnet design
expectations and to the target field quality for LHC. Many
corrector circuits will be powered in a way which
cannot be predicted before LHC will start operation
and which even then may change between physics
runs. The measured magnetic hysteresis and its
influence on possible setting errors during operation is
discussed, in particular for the orbit correctors and the
tuning/trim quadrupole magnet circuits.
CERN - Geneva
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
127-969 - Comparison of Three Designs of Wide
Aperture Dipole for SIS300 Ring
Leonid Tkachenko, Igor Bogdanov, Sergey Kozub, Petr
Shcherbakov, Pavel Slabodchikov, Veniamin Sytnik,
Vasiliy Zubko (IHEP Protvino, Protvino, Moscow
Region), Juris Kaugerts, Gebhard Moritz (GSI,
Darmstadt)
The GSI Fast-Pulsed Synchrotron Project is found now
under development. The last stage of this machine is
the SIS300 ring, which will use superconducting
dipoles with 100-mm aperture, 6-T magnetic field
amplitude and 1-T/s field ramp rate. This dipole has to
posses minimal heat losses both in the coil and in the
iron yoke. This article considers three designs of such
dipole. The main distinction of these designs is the
different thickness of stainless steel collars, which are
supported the coil. The collars in the first design hold
all forces arisen in the magnet. The second design
needs collars only for assembly of the coil and cooling
down of the magnet. An iron yoke in this design will
withstand ponderomotive forces. The third design has
no collars and the iron yoke will hold all forces,
including preload, forces originated during cooling
down and ponderomotive forces. The different
mechanical, magnetic and thermal characteristics are
presented and comparative analysis of these designs is
carried out.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
128-971 - Ways of Reduction of Cable Losses in
Fast-Cycling Dipole for SIS300 Ring
Leonid Tkachenko, Igor Bogdanov, Sergey Kozub, Petr
Shcherbakov, Pavel Slabodchikov, Vasiliy Zubko
(IHEP Protvino, Protvino, Moscow Region), Juris
Kaugerts, Gebhard Moritz (GSI, Darmstadt), Martin
Wilson (Oxford Instruments, Oxford, Oxon)
The new synchrotron facility is designed for the
acceleration of high intensity and high-energy ion and
proton beams in the GSI, Darmstadt. The main
magnetic element of the second stage (SIS300) of this
machine is superconducting dipoles with 100-mm
aperture, 6-T magnetic field amplitude and 1-T/s field
ramp rate. The main requirements for these magnets in
addition to high field quality are minimal heat losses
both in the coil and in the iron yoke at available
temperature margin. Gain of the temperature margin
can be reached by increasing of the superconducting
strands in the cable. But increasing of the number of
the strands in the cable results a growth of the cable
width. As cable heat losses are proportional to a forth
order of the cable width, they rise essentially. This
article considers and analyses different ways of reduction of
cable heat losses. The calculated results of heat losses for
different geometries based on various cable designs are
presented. The optimal parameters of the cable design,
based on the computer simulations, are chosen.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
129-976 - Magnetic Field Measurements of the LHC
Inner Triplet Quadrupoles Produced at Fermilab
Gueorgui Velev, Joseph DiMarco, Sandor Feher, Henry
Glass, James Kerby, Michael Lamm, Phil Schlabach, James
Strait, Mike Tartaglia, John Tompkins, Alexander V. Zlobin
(Fermilab, Batavia, Illinois)
Production of 18 superconducting low-beta quadrupoles
(MQXB) for the LHC is well advanced. These 5.5 m long
magnets are designed to operate at 1.9 K with a peak field
gradient of 215 T/m in the 70 mm apertures. Two MQXB
cold masses with a dipole orbit corrector between them form
a single cryogenic unit (LQXB) which is the Q2 optical
element of the final focus triplets in the LHC interaction
regions. A program of magnetic field quality and alignment
measurements of the cold masses are performed at room
temperature during magnet fabrication and LQXB assembly
as well as at superfluid helium temperature. Results of these
measurements are summarized in this paper.
Work supported by the U.S. Department of Energy
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
130-980 - Measurements of the Sextupole Dynamic
Effects in Tevatron Dipole Magnets
Gueorgui Velev, Jerry Annala, Pierre Bauer, Joseph
DiMarco, Henry Glass, Ray Hanft, Robert Kephart, Michael
Lamm, Mike Martens, Phil Schlabach, Mike Tartaglia, John
Tompkins (Fermilab, Batavia, Illinois)
To optimize the performance of the Fermilab Tevatron
accelerator in Collider Run II, we have undertaken a
systematic study of the drift and subsequent snapback of
dipole magnet harmonics. The study has mostly focused on
the dynamic behavior of the normal sextupole component,
b2, as measured in a sample of spare Tevatron dipoles at the
Fermilab Magnet Test Facility. We measured the
dependence of the decay amplitude and the snapback time
on Tevatron ramp parameters and magnet operational
history. A series of beam studies was also performed [*].
This paper summarizes the magnetic measurement results
and describes an optimization of the b2 correction scheme
which is derived from these measurements.
Work supported by the U.S. Department of Energy
* P.Bauer et al. These proceedings.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
131-1009 - Study of Thermal Stability and Quench
Process of HTS Dipole
Vasiliy Zubko, Igor Bogdanov, Sergey Kozub, Petr
Shcherbakov, Leonid Tkachenko (IHEP Protvino, Protvino,
Moscow Region)
The dipole with a coil made from HTS composite on a
Bi2223 basis and placed in the ferromagnetic yoke has been
developed and produced in IHEP. A designed magnetic field
of the dipole in 20-mm aperture is 1 T at temperature of
liquid nitrogen. The numerical analysis of factors,
having influence on thermal stability of the magnet, as
well as the computer simulations of dipole heating
during quench was carried out. An anisotropy of
voltage-current characteristics of HTS tapes in a
magnetic field is taken into account in calculations of
quench process. The measured results of voltagecurrent characteristics during powering and quench of
the coil are in a good agreement with the numerical
calculations
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
132-1010 - Stability of Fast-cycling Dipole for
SIS300 Ring
Vasiliy Zubko, Igor Bogdanov, Sergey Kozub, Petr
Shcherbakov, Leonid Tkachenko, Sergey Zintchenko
(IHEP Protvino, Protvino, Moscow Region), Marian
Kauschke, Gebhard Moritz (GSI, Darmstadt)
Funding
AgencyShould
not
exceed
200
charactersFootnotesFootnotes: Not exceeding 200
chaThe main requirement to the superconducting
dipole with 100-mm aperture, 6-T magnetic field
amplitude and 1-T/s field ramp rate for the SIS300
accelerator, developed in the GSI, Darmstadt, is a
stability of the magnet influenced by various heat
releases arising during operation mode. The computer
simulation of the heating of superconducting dipoles
and cooling helium during the SIS300 operating cycle
was carried out. The analysis of stability is based on
the numerical solution of the heat balance equation in
the coil and in a single?phase helium flow.
Temperature margin of the superconducting dipole
during the SIS300 operating cycle was calculated.
Possible ways to increase the temperature margin are
discussed.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
133-1013 - Study of Quench Process in Fast-cycling
Dipole for SIS300 Ring
Igor Bogdanov, Sergey Kozub, Petr Shcherbakov,
Leonid Tkachenko, Sergey Zintchenko, Vasiliy Zubko
(IHEP Protvino, Protvino, Moscow Region), Juris
Kaugerts, Gebhard Moritz (GSI, Darmstadt)
The results of numerical quench process simulation in
the coil of superconducting dipole with magnetic field
of 6 T and 100-mm aperture for high-energy ion and
proton synchrotron facility SIS300 are presented. The
peculiarities of quench process developed in dipole are
discussed for several variants of quench conditions.
The coil quench behavior determines the features,
scopes, and limitations in possible quench protection
scheme. Main design characteristics of the preferable
protection system are considered.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
134-1076 - Design Issues for the Superconducting
Focusing Magnet that goes around a Liquid Hydrogen
Absorber for the Muon Ionization Cooling Experiment
(MICE)
Michael Green, Giles Barr, Cobb John, Wing Lau,
Stephanie Yang (OXFORDphysics, Oxford, Oxon), Elwyn
Baynham, James Rochford (CCLRC/RAL/ASTeC, Chilton,
Didcot, Oxon)
This report describes the design issues that are associated
with a superconducting focusing solenoid that goes around a
liquid hydrogen absorber for the Muon Ionization Cooling
Experiment (MICE) proposed for the Rutherford Appleton
Laboratory. The solenoid consists of two superconducting
coils that may operated at the same polarity or at opposite
polarities. As a result, the coils and their support structure
must be designed to carry a 300 ton inter-coil force that is
forcing the coils apart along their axis. The basic design
parameters for the focusing magnet are discussed. The
magnet and its cryostat are designed so that the absorber can
be assembled and tested before installation into the pretested focusing solenoid. A safety requirements for MICE
dictate that the insulating vacuum for the superconducting
magnet be separated from the insulating vacuum for the
absorber and that both vacuum be separated from the
experiment vacuum and the vacuum within adjacent RF
cavities. The safety issues associated with the arrangement
of the various vacuums in the MICE focusing modules are
presented. The effect of magnet operation and magnet
quench on the liquid hydrogen absorber is also discussed.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
135-1111 - Design and Study of a Superferric Model
Dipole and Quadrupole Magnets for the GSI Fast-pulsed
Synchrotron SIS100.
Alexander Kovalenko, Nicolai Agapov, Victor Bartenev,
Alexei Donyagin, Hamlet Khodzhibagiyan, Grigori
Kuznetsov, Anatoly Smirnov, Michail Voevodin (JINR,
Dubna, Moscow Region), Egbert Fischer, Guenter Hess,
Gebhard Moritz, Carsten Muehle (GSI, Darmstadt)
New experimental results from the investigation of a model
superferric Nuclotron-type dipole and quadrupole magnets
are presented. The magnets operate at pulse repetition rate f
= 1Hz, providing peak magnetic field B = 2 T and the field
gradient G = 34 T/m in the dipoles and quadrupoles
respectively. The superconducting coil is made from a
hollow multi-filamentary NbTi cable cooled with two phase
helium flow. Different possibilities were investigated to
reduce AC power losses in the case of a cold iron yoke
(T=4.5K). The achieved results are discussed. The value of
9W/m has been obtained for dipole magnet with the yoke at
T=50K. The first 50 K yoke quadrupole was designed and
tested. Other problems, connected with the magnetic field
quality, mechanical and cryogenic stability of the magnets
under SIS100 operating conditions are also discussed.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
136-1301 - The Geometry of the LHC Main Dipole
Elena Wildner, Giuseppe Gubello, Beauquis Jerome, Marco
La China, Walter Scandale (CERN, Geneva)
The 15 m long main dipole of the Large Hadron Collider has
a curvature following the beam trajectory with the aim to
minimize the necessary coil aperture. To avoid feeddown effects and mechanical aperture restrictions
strong constraints have to be imposed on the
construction of the magnet in terms of tolerances and
stability of the cold mass during transport, cryostating,
cold tests and installation in the LHC tunnel. In this
paper we show the behaviour of the shape of the
magnet using available measurements taken at different
stages of construction and assembly. In particular we
discuss the evolution of the sagitta and the positioning
of the corrector magnets that are used to compensate
the multipole field errors. We propose alignment
procedures to be used in case magnets are out of
tolerance after transport and cold tests. The twist of the
magnet and its relation to the field angle will also be
discussed.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
137-1307 - Fast Pulsed SC Magnets
Gebhard Moritz (GSI, Darmstadt)
The demand for high beam intensities leads to the
requirement of fast pulsed magnets for synchrotrons.
An example is the proposed 'International Facility for
Beams of Ions and Antiprotons' at GSI, which will
consist of two synchrotrons in one tunnel and several
storage rings. The high field ramp rate and repetition
frequency introduce many magnet design problems and
constraints in the operation of the accelerator.
Persistent currents in the superconductor and eddy
currents in wire, cable, iron and vacuum chamber
reduce the field quality and generate cryogenic losses.
Due to the large number of magnet cycles during the
lifetime of such a magnet, special attention has to be
paid to magnet material fatigue problems. The large
charging voltages put some constraints on the use of
cold diodes for quench protection. R&D has started at
GSI, in collaboration with many institutions, to comply
with the constraints mentioned above. Model dipoles
were built and tested. The results of the R&D are
reported. The advantages of the use of low field, fast
pulsed superconducting, compared to resistive,
magnets will be discussed
Type of presentation requested: This is an Invited
Oral Presentation
Classification: [T10] Superconducting Magnets
138-1309 - Determination of the Evolution of the
LHC Main Dipole Field Orientation from
Measurements in Industry and at CERN
Christine Vollinger, Paolo Fessia, Juan Garcia Perez,
Marco La China, Walter Scandale, Ezio Todesco,
Elena Wildner (CERN, Geneva)
Besides the main field strength, the main field
orientation is an important parameter for the
performance of the LHC. A field orientation out of
tolerance reduces the margin of the available vertical
corrector strength. Measurements after magnet cold test
show field directions at the tolerance limits and in
some cases exceeding these. Since currently no
measurements of the field orientation with respect to
the cold mass mechanical plane are available from
industry, a measurement device has been developed at
CERN to allow a fast and easy way of determining the
average field angle of the magnets. A test cycle has been
started which permits the comparison of the obtained
measurement results with results from the classical rotating
coil measurements of the magnetic field. In this paper, we
present these measurement results and an analysis of
possible sources of a bad field orientation. The assembly
procedure and tolerances of the mechanical components
have been investigated with respect to the field orientation.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
139-1336 - 2nd Generation LHC IR Quadrupoles Based
on Nb3Sn Racetrack Coils
Vadim Kashikhin, James Strait, Alexander V. Zlobin
(Fermilab, Batavia, Illinois)
After the LHC operates for several years at nominal
parameters, it will be necessary to upgrade it for higher
luminosity. Replacing the baseline NbTi low-beta
quadrupoles with a higher performance magnets based on
advanced superconducting materials and magnet
technologies is one of the most straightforward ways in this
direction. Preliminary studies show that high-performance
Nb3Sn strands to be available within the next few years
allow increasing the quadrupole aperture up to 110 mm
using a 4-layer shell-type coil and providing the same 200
T/m field gradient with 20% margin as the baseline
magnets. It will allow reduction of b* by a factor of 3. An
alternative approach to the quadrupole design is based on
simple flat racetrack coils. This paper discusses the
possibilities and limitations of large-aperture racetrack
quadrupole designs and compares them to the shell-type
magnets.
U.S. Department of Energy
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
140-1361 - A Model for Determining Magnet Costs
Robert Palmer, J. Scott Berg (BNL, Upton, Long Island,
New York)
One of the most important considerations in designing large
accelerators is cost.
Magnet costs are a significant
component of that. This paper describes a model for
estimating magnet costs. The reasoning behind the cost
model is explained, and the parameters of the model are
chosen so as to correctly give the costs for existing magnets.
Supported by US Department of Energy contract DE-AC0298CH10886
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
141-1605 - Series Production of the LHC MAin Dipole
Cold Masses
Gijsbert De Rijk, Marta Bajko, Marc Cornelis, Paolo
Fessia, John Miles, Michele Modena, Jean Rinn, Frederic
Savary, Jos Vlogaert (CERN, Geneva)
The series production of the LHC main dipole cold masses
is now well underway in all three production companies. In
total more than 170 cold masses have been delivered by the
end of 2003. We present here some aspects concerning the
tooling optimisation and quality control. We will evoke the
coil size control and longitudinal welding optimisation.
Some of the difficulties encountered during the series
production will be discussed as well as the measures
taken to cure the unsatisfactory quenching performance
of a few magnets.
Type of presentation requested: Poster
Classification: [T10] Superconducting Magnets
142-291 - High Charge Transfer Operation of Light
Trigged Thrystor Crowbars
Wolfhard Merz (DESY, Hamburg)
High power klystrons are protected by the application
of crowbar switches. The closing switch approach is
most commonly used. It is characterized by
establishing a short circuit path to bypass the klystron
fault current. During short circuit operation the
crowbar switch must be capable to carry both puls
current of the filter capacitor and follow through
current of the high voltage dc power supply.
Depending on the main circuit parameters both the
capacitor charge and the follow through charge can
achieve significant amounts. The application of line
controlled and uncontrolled hvdc power converters
requires special attention regarding the follow through
current charge transfer. This paper presents first
practical results of series connected Light Triggered
Thyristors (LTT) operating as closing crowbar
switches. Measured data are discussed, which have
been obtained from the DESY-II installation operating
with thyristor controllers and the PETRA installation
operating with uncontrolled rectifiers. Beside the puls
operation the follow through current capability of the
crowbar is pointed out.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
143-420 - Reducing Output Current Ripple of
Power Supply with Component Replacement
Kuo-Bin Liu (NSRRC, Hsinchu)
Correction magnets of synchrotron storage ring are
served with linear power supplies (correction power
supply) with 100 ppm output current ripple in National
Synchrotron Radiation Research Center. Reducing
output current ripple of correction power supply might
reduce perturbation of beam position of storage ring.
Replace correction power supplies with lower output
current ripple ones is straightforward but costs lots of
money. Without adding any other circuit and electronic
component, some components of correction power
supply are replaced by ones with more precious and
lower output fluctuation; so that the same circuitry
structure of correction power supply is kept without
increasing its complexity and could reach 25 ppm
output current ripple.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
144-448 - Developments in Magnet Power
Converters at the SRS
Graham David Charnley (CCLRC/DL/ASTeC,
Daresbury, Warrington, Cheshire)
A project to upgrade the magnet power converters of
the SRS has commenced to ensure its efficient
operation for its remaining operational lifetime. A
recent risk analysis of the facilities equipment
identified that the main areas for concern were the Storage
Ring magnet power converters, kicker and septum pulse
power supplies and the Booster Dipole "White Circuit" and
associated power converters. This report detail the
development and replacement programs currently active at
Daresbury Laboratory, including future work identified to
support and improve SRS utilisation.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
145-495 - Performance of a Superconducting Multipole
Wiggler Power Supplies at NSRRC
Yuan-Chen Chien, Kuo-Tung Hsu, Ching-Shiang Hwang,
Fu-Yuan Lin, Kuo-Bin Liu (NSRRC, Hsinchu)
A new Superconducting Multipole Wiggler Magnet
(SMPW6) was constructed and installed at NSRRC.To
ensure the SMPW6 in the superconducting state generate the
designed peak magnetic strength and strength profile, stable
annd precision current mode power supplies are required. A
Danfysik System 8000 power supply for superconducting
magnet is used to provide the main current to the coil, two
Kepco linear mode power supplies are also installed to trim
the overall flux strength. In order to reach the predefined
specifications, two difficulties had to be conqured first. One
is at the chaging phase, a slew rate control circuit had to be
implemented to prevent SMPW6 quench error. The other is
the mutual coupling problem caused by hooking the main
power supply and the two trimming power supplies. This
coupling resulted in more voltage fluctuation, which in turn
produced heat inside the coil. In this paper, due to a
designed digital controlled slew rate mechanism and
inserted decoupling resistors in series with the trimming
power supplies, the overall performance and stability of the
SMPW6 is greatly improved.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
146-688 - Design and Implementation a Switching
Bipolar Power Stage of the Correction Power Supply
Chen-Yao Liu, Kuo-Bin Liu (NSRRC, Hsinchu)
In order to enhance efficiency of the correction power
supply, the switching mode bipolar power stage was to
implement and to substitute for the original power stage of
the correction power supply. To ensure higher efficiency,
the programming dc bus voltage of the power stage of the
correction power supply must be working in accordance
with the output current state and load. A new power
conversion stage was constructed and employs power
MOSFET operating at higher switching frequency then old
60 Hz energy conversion mode system. This will not only
improve the efficiency but also decrease the weight of the
correction power supply. The new switching mode power
stage supply a bipolar power dc bus power and automatic
turning working voltage by the feedback balance circuit.
Results and working performance will be presented in this
paper.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
147-839 - 52 kV Power Supply for Energy Recovery
Linac Prototype RF
Justin Edward Theed, Christopher White (CCLRC/DL,
Daresbury, Warrington, Cheshire), Graham David
Charnley, Mike Dykes, Andy Gallagher, Stephen A.
Griffiths, Andrew Moss, Joseph Orrett
(CCLRC/DL/ASTeC, Daresbury, Warrington,
Cheshire)
Daresbury Laboratory is constructing a RadioFrequency (RF) Test Facility to be capable of testing
RF cavities for accelerator applications. Electrical
power for the RF equipment will be provided from an
existing -52 kV 6-pulse rectifier and transformer
system capable of delivering 16A DC continuous
current. A crowbar circuit will be provided to divert
the large amount of stored energy in the smoothing
capacitor bank in the event that a spark should occur
between the cathode and the body or modulating
anode. Traditionally, the crowbar has been provided
by using an ignitron, but modern solid state devices
have sufficient performance to meet the requirements.
This paper discusses the numerous design options that
were considered for the circuit parameters.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
148-874 - A New Current Regulator for the APS
Storage Ring Correction Magnet Bipolar Switching
Mode Power Converters
Ju Wang (ANL, Argonne, Illinois)
The correction magnets in the Advanced Photon
Source's storage ring are powered by PWM-controlled
bipolar switching-mode converters. These converters
are designed to operate at up to +/- 150 A. The original
current regulator used a polarity detection circuit, with
a hysteresis, to determine which IGBT was needed to
regulate the current with a given polarity. Only the
required IGBT was switched while others were held on
or off continuously. The overall IGBT switching losses
were minimized by the design. The shortcoming of the
design is that the converter's output is unstable near
zero current because of the hysteresis. To improve the
stability, a new current regulator, using a different
PWM method, has been designed to eliminate the
requirement of the polarity detection. With the new
design, converters can operate smoothly in the full
range of +/-150 A. The new design also meets tighter
specs in terms of the ripple current and dynamic
response. This paper describes the design of the new
regulator and the test results.
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: [T11] Power Supplies
149-996 - SPEAR3 DC Intermediate Magnet Power
Supplies
Antonio Carlos de Lira, Paul Bellomo (SLAC, Menlo
Park, California)
The Stanford Synchrotron Radiation Laboratory
(SSRL) has successfully commissioned SPEAR3, its
newly upgraded 3-GeV synchrotron light source. First
stored beam occurred December 15, 2003 and 100mA
operation was reached on January 20, 2004. This paper
describes the specification, design, and performance of the
SPEAR3 intermediate DC magnet power supplies (IPS) that
consist of tightly-regulated (better than 10 ppm) current
sources ranging from 60 A to 500 A and output powers
ranging from a few kW to 22.5kW. A total of 69 IPS are in
successful operation. The SPEAR 3 upgrade performance
and reliability requirements mandated new power supplies
for both the SPEAR3 storage ring, and for the booster-toSPEAR3 transport line. IPS are widely used at SPEAR3 to
power single quadrupoles, dipoles, families of quadrupoles
and sextupoles, and also on the Titanium sublimation
pumps. IPS' topology allows them to be series operated for
those magnet strings requiring higher voltages. A compact
19" standard rack-mounted design is common to all the
units. These are off-line, switch-mode, operating at 16 kHz
to reduce space and provide for fast output response and
high efficiency.
Work supported by the U.S. Department of Energy under
contract DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [T11] Power Supplies
150-997 - SPEAR3 DC Magnet Large Current Power
Supplies
Antonio Carlos de Lira, Paul Bellomo (SLAC, Menlo Park,
California)
The Stanford Synchrotron Radiation Laboratory (SSRL) has
successfully commissioned SPEAR3, its newly upgraded 3GeV synchrotron light source. First stored beam occurred
December 15, 2003 and 100mA operation was reached on
January 20, 2004. This paper describes the specification,
design, and performance of the SPEAR3 DC magnet large
power supplies (LGPS) that consist of tightly-regulated
(better than 10 ppm) current sources ranging from 100 A to
225 A and output powers ranging from 70kW to 135kW. A
total of 6 LGPS are in successful operation and are used to
power strings of quadrupoles, and sextupoles. The LGPS are
isolated by a delta/delta-wye 60Hz step-down transformer
that provide power to 2 series connected chopper stages
operating phase-shifted at a 16 kHz switching frequency to
provide for fast output response and high efficiency. Also
described are outside procurement aspects, installation, inhouse testing, and operation of the power supplies.
Work supported by the U.S. Department of Energy under
contract DE-AC03-76SF00515
Type of presentation requested: Poster
Classification: [T11] Power Supplies
151-1084 - Development of Dual Resonant Frequency
Magnet Power Supply
Shinji Yamanaka (KEK, Ibaraki)
In the resonant-frequency for use in a rapid cycling
synchrotron, the reset period was the same as the accelerator
period. By using a dual resonant-frequency power supply,
the reset period can be made shorter than the accelerator one
for obtaining a rapid cycle. The solutions are presented for
the noise problems produced by frequency switching, the
difficulties concerning harmonics control and the tracking
between a quadrupole magnet and a dipole one. In this
report, the formulation of a dual resonant-frequency power
supply is shown together with the results of test operation
using a model circuit with the switching device of
Insulated Gate Bipolar Transistor (IGBT). A practical
useful magnet power supply system is now realized for
the rapid cycling synchrotron accelerator.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
152-1148 - Installation and Operation of a New
Klystron Power Supply Having a Fast Solid-state
High-voltage Switch for Klystron Protection in the
Photon Factory Storage Ring
Shogo Sakanaka, Masaaki Izawa, Takeshi Takahashi,
Kensei Umemori (KEK, Ibaraki)
In the 2.5-GeV Photon Factory storage ring at KEK,
there are four klystron power supplies which typically
operate at an output voltage of -40 kV with 8 A. We
replaced one of these power supplies during 2003 and
the new power supply is in operation. This power
supply is equipped with a solid-state high-voltage (HV)
switch for klystron protection. This HV switch is made
up of eighty insulated gate bipolar transistors (IGBT),
and it can turn the high-voltage off within a few tens of
microseconds in cases of any discharges in the
klystrons. We report the performance of this new
power supply.
Type of presentation requested: Poster
Classification: [T11] Power Supplies
153-1112 - Auto-filling Cryogenic System for
Superconducting Magnet
Fu-Yuan Lin, Cheng-Hsiang Chang, Tai-Ching Fan,
Ching-Shiang Hwang (NSRRC, Hsinchu)
A 3.2 Tesla superconducting wiggler with period
length of 6.0 cm (SW6) was installed in January of
2004 at the National Synchrotron Radiation Research
Center
(NSRRC).
A
cryogenic
plant
for
superconducting rf cavity will also provide liquid
helium and liquid nitrogen for SW6 by using an
independent automatic filling system. To facilitate a
stable and precise auto-filling process, a PID controller,
the kernel of the auto-filling system, will control the
valves of liquid helium and liquid nitrogen,
respectively. The authors shall present the control
algorithm of different operation modes, namely the
pre-cooling mode and normal auto-filling mode. The
boil off rate of liquid helium and liquid nitrogen will be
discussed.
Type of presentation requested: Poster
Classification: [T13] Cryogenics
154-1142 - The Design of Cold to Warm Transitions
of the LHC
Juan Knaster, Berthold Jenninger, D&#233;lio Duarte
Ramos, Gaelle Ratcliffe, Raymond Veness (CERN,
Geneva)
The Large Hadron Collider (LHC) is the next
accelerator being constructed on the CERN site to be
operational in 2007. It will accelerate and collide 7
TeV protons and heavier ions up to lead. More than
2000 cryomagnets working at 1.9 or 4.5 k will form
part of the magnetic lattice of the LHC. The transitions
from cryogenic temperatures to room temperature
zones will be achieved by 200 cold to warm transitions
(CWTs). The CWTs will compensate for longitudinal and
transversal displacements between beam screens and cold
bores, ensuring vacuum continuity without limiting the
aperture for the beam. The transverse impedance
contribution is kept below the assigned total budget of 1
M&#937;/m by means of a 5 &#956;m thick Cu coating that
also minimises the dynamic heat load through image
currents. Tests have been performed that confirm that the
static heat load per CWT to the cryomagnets remains below
2.5 W, hence validating the design.
Type of presentation requested: Poster
Classification: [T13] Cryogenics
155-102 - Fabrication of Dipole Vacuum Chambers for
INDUS-2
Vivek Kumar Bhatnagar, Animesh Kumar Jain (CAT, Indore
(M.P.))
The Indus- 2 dipole vacuum chamber is a 3.6 metre long
aluminum alloy chamber, which is fabricated from two thick
plates of grade AA 5083 H321. These chambers will be
installed in the 2.5 Gev electron storage ring of synchrotron
radiation source at the Centre for Cdvanced Technology,
Indore. Each half of the chamber is complex in shape and it
is machined by using CNC Profiler m/c. Manual TIG
welding process is adopted in fabrication.
Nineteen
chambers out of a total of twenty have been successfully
completed and vacuum leak tested to the design target i.e.
2.0 x 10&#8254; ¹º mbar ltrs./ sec. and eleven nos. of
vacuum chambers have passed ultimate vacuum tests. This
paper describes the fabrication aspects of dipole vacuum
chamber.
Centre for Advanced Technology, Indore,
(Department of Atomic Energy)
INDIA
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
156-222 - Present Status of the Storage Ring UHV
System of NSRL
Yong Wang (USTC/NSRL, Hefei, Anhui)
The upgrade Storage Ring UHV System of HLS Project II
had been completed in 2003, and the light source
modification started at September 1. In November 16, the
improvement object of HLS Project II, the beam of 300 mA
at 800 MeV was measured. Now the sum beam dose is
about 100 A.hr, and the beam lifetime is over 8 hr at 300
mA and 800 MeV.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
157-238 - The LHC Beam Vacuum Chamber Prototype
with Woven Carbon Fiber Cryosorber
Rodion Dostovalov, Vadim Anashin, Alexandre Krasnov
(BINP, Novosibirsk)
The beam vacuum chamber inside some cryogenic elements
in the LHC long straight sections will have cold bore
temperature of 4.5K and a beam screen at temperature
between 5 and 20 K. The gas molecules desorbed due to
photons, electrons and ions will pass through the slots on the
beam screen to the shadowed part between the cold bore and
the beam screen. All desorbed gases except H2 could be readsorbed on the cold bore or on the beam screen but a
cryosorber is required to pump H2. The cryosorption studies
of LHC beam vacuum chamber prototype with woven
carbon fiber material are performed in the Budker
Institute of Nuclear Physics (BINP) within the
framework of collaboration BINP-CERN. The results
show that 100-200 cm**2 of woven carbon fiber has
sorption capacity more than 1E20 molecules at
temperature lower than 29K and equilibrium hydrogen
density less than 1E15 molecule/m**3, that meet the
LHC requirements. The additional studies of dynamic
pressure behavior at the beam screen temperature
oscillations were performed. These results help to
predict the dynamic pressure at nonstandard or
transient regimes of the LHC operation.
This work was supported by CERN AT Division
vacuum group.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
158-267 - New Methods of Heterogeneous Materials
Welding in Accelerating Structures
Vardan Avagyan (CANDLE, Yerevan)
Present methods of the joining of heterogeneous
materials do not always provide the obtaining of
transitional elements, which meet working conditions,
such as: deep vacuum, high pressure, temperature
cyclic changing in the range from 4.2 up to 623 K, high
vibration, radiation etc. It is explained by the fact that
the welding or the brazing of heterogeneous materials
present great problems because of the possibility to
form embrittlement at their interaction with each other
as well as with newly formed phases. In spite of that,
the application of heterogeneous materials welding can
appreciably modify the quality and the principle of the
designed devices.The results of the joining of
heterogeneous materials, such as titanium with
stainless steel (serviceable at 4.2 K), copper with
aluminum, titanium with niobium (this work has been
carried out for TESLA project), stainless steel with
aluminum, copper with stainless steel are presented in
this work.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
159-459 - Secondary Electron Yield Measurements
from Thin Surface Coatings for NLC
Frederic Le Pimpec, Mauro Torino Francesco Pivi
(SLAC/NLC, Menlo Park, California), Frank King,
Robert Kirby (SLAC, Menlo Park, California)
In the beam pipe of the positron damping ring of the
Next Linear Collider, electrons will be created by beam
interaction with the surrounding vacuum chamber wall
and give rise to an electron cloud. Several solutions are
possible for avoiding the electron cloud, without
changing the beam bunch structure or the diameter of
the vacuum chamber. Some of the currently available
solutions include reducing residual gas ionization by
the beam, minimizing photon-induced electron
production, and lowering the secondary electron yield
(SEY) of the chamber wall. We will report on recent
SEY measurements performed at SLAC on TiN
coatings and TiZrV non-evaporable getter thin films.
Work supported by the U.S. Department of Energy under
contract number DE-AC03-76SF00515.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
160-497 - The Vacuum System of the Australian
Synchrotron
Erhard Huttel (FZK-ISS-ANKA, Karlsruhe), Bill Barg, Alan
Jackson, Brad Mountford (ASP, Melbourne)
A 3 GeV Synchrotron Radiation Source is being built in
Melbourne, Australia. The storage ring has a circumference
of 216 m and has a 14 fold DBA structure. The vacuum
chambers of the storage ring will be made from stainless
steel. They consist of a beam chamber (width 70, height
32mm ) connected to an ante chamber, where lumped
absorbers and lumped ion pumps are installed. No
distributed absorber and pumps are foreseen. The nominal
pumping speed of the complete ring is 31 000 l/s. The
vacuum chamber of an achromat will be baked ex situ and
installed under vacuum. The design of the chamber, the
pump configuration and the expected vacuum behaviour will
be presented.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
161-864 - Clearing Electrodes for Vacuum Monitoring at
the Fermilab Recycler
Daniel Robert Broemmelsiek (Fermilab, Batavia, Illinois)
The Fermilab Recycler is a fixed 3.3-km 8-GeV kinetic
energy storage ring located in the Fermilab Main Injector
tunnel. Each split-plate beam position monitor in the
Recycler is also used to generated an ion clearing field for
ions trapped by the antiproton beam. Approximately 100
locations have been instrumented with pico-amp meters to
measure the electron current, generated by the beam-ionized
residual gas in the vacuum chamber. This electron current is
found to be proportional to the beam current and to the
residual gas pressure in the Recycler and may be used to
monitor the Recycler vacuum.
U.S. Department of Energy
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
162-981 - Secondary Electron Emission Measurements
for TiN Coating on Stainless Steel of SNS Accumulator
Ring Vacuum Chamber
Ping He, Hsiao-Chaun Hseuh, Robert J. Todd (BNL, Upton,
Long Island, New York), Bernard Henrist, Noel Hilleret
(CERN, Geneva), Shigeki Kato (KEK, Ibaraki), Mauro
Torino Francesco Pivi (LBNL/AFR, Berkeley, California;
SLAC/NLC, Menlo Park, California), Rob
BNL is responsible for the design and construction of the
US Spallation Neutron Source (SNS) accumulator ring.
Titanium Nitride(TiN) coating on the stainless steel vacuum
chamber of the SNS accumulator ring is needed to reduce
undesirable resonant multiplication of electrons. The
Secondary Electron Yield(SEY) of TiN coated chamber
material has been measured after coated samples were
exposed to air and after electron and ion conditioning. We
are reporting about the TiN coating system setup at BNL
and SEY measurements results performed at CERN, SLAC
and KEK. We also present updated electron-cloud
simulation results for the SNS accumulator assuming
different SEY values.
Work performed under the auspices of the U.S.
Department of Energy
Work supported by the U.S. Department of Energy
under contract number at SLAC : DE-AC0376SF00515
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
163-1000 - The Vacuum System of Super SOR
Hiroshi Sakai, Masami Fujisawa, Akihito Kakizaki,
Toyohiko Kinishita, Hirofumi Kudo, Norio Nakamura,
Taichi Okuda, Takashi Shibuya, Kenji Shinoe, Hiroyuki
Takaki (ISSP/SRL, Chiba), Haruo Ohkuma
(JASRI/SPring-8, Hyogo), Masanori Kobayashi (KEK,
Ibaraki), S
The Super-SOR light source is a Japanese VUV and
soft X-ray third-generation synchrotron radiation
source, which consists of 1.8GeV storage ring and
injector. The beam current is circulated up to 400mA.
These accelerators are designed so as to fully meet
requirements for top-up injection. In order to realize
these operation modes, our vacuum system are required
on following conditions. One is to obtain the long
lifetime. The other is not to melt the vacuum chamber
by irradiating the high flux synchrotron radiation.
Finally beam instability is not occurred by large wake
fields. We describe the design of the vaccum chamber
of Super-SOR and present the recent R&D concerning
this system.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
164-1044 - A High Conductance Vacuum Vessel and
Polymer High Voltage Insulating Column for the
ISIS RFQ Ion Source
Michael A. Clarke-Gayther (CCLRC/RAL/ASTeC,
Chilton, Didcot, Oxon)
A compact, high conductance vacuum vessel and an
advanced composite polymer, high voltage insulating
column have been designed for the ISIS RFQ Ion
Source. Key features of the monolithic, glass fibre
reinforced, PolyPhenyleneOxide (PPO) insulator
design are highlighted. Results obtained from a two
dimensional finite element analysis of electric field,
from vacuum out-gassing tests on a range of polymers,
and from pull-out tests on stainless steel inserts in PPO
and ceramic are presented.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
165-1122 - Beam-loss Induced Pressure Rise of LHC
Collimator Materials Irradiated with 158 GeV/u
In49+ Ions at the CERN SPS
Edgar Mahner, Ilias Efthymiopoulos, Jan Hansen, Eric
Page (CERN, Geneva)
During heavy ion operation, large pressure rises, up to
a few orders of magnitude, were observed at CERN,
GSI, and BNL. The dynamic pressure rises were
triggered by lost beam ions that impacted onto the
vacuum chamber walls and desorbed about 10E4 to
10E7 molecules per ion. The deterioration of the dynamic
vacuum conditions can enhance charge-exchange beam
losses and can lead to beam instabilities or even to beam
abortion triggered by vacuum interlocks. Consequently, a
dedicated measurement of heavy-ion induced molecular
desorption in the GeV/u energy range is important for LHC
ion operation. In 2003, a desorption experiment was
installed at the SPS to measure the beam-loss induced
pressure rise of potential LHC collimator materials. Samples
of bare graphite, sputter coated (Cu, TiZrV) graphite, and
316 LN stainless steel, were irradiated under grazing angle
with 158 GeV/u indium ions. After a description of the new
experimental set-up, the results of the pressure rise
measurements are presented, and the derived desorption
yields are compared with data from other experiments.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
166-1280 - R&D Vacuum Issues of the Future GSI
Accelerator Facilities
Hartmut Reich Sprenger (GSI, Darmstadt)
The new GSI accelerator facilities are planned to deliver
heavy ion beams of increased energy and highest intensity.
Whereas the energy is planned to be increased roughly by a
factor of 10, the ion beam intensities are planned to be
enlarged by three orders of magnitude. To achieve highest
beam intensities, medium charged heavy ions (e.g. U28+)
are accelerated. Since the ionization cross sections for these
ions are comparably high, a UHV-accelerator system with a
base pressure in the low 10-12mbar regime is required, even
under the influence of ion beam loss induced desorption
processes. An intensive program was started to upgrade the
UHV system of the existing synchrotron SIS18 (bakeable)
and to design and lay out the UHV systems of the future
synchrotron SIS100 and SIS300 (mainly cryogenic). The
strategy of this program includes basic research on the
physics of the ion induced desorption effects as well as
technical developments, design and prototyping on bakeable
UHV components (vacuum chambers, diagnostics, bakeoutcontrol, pumping speed), collimator for controlled ion beam
loss, NEG coating and cryogenic vacuum components.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
167-1429 - Pressure Field Distribution in a Cylindrical
Geometry with Arbitrary Cross Section
Francisco Tadeu Degasperi (FATEC-SP, Sao Paulo, SP),
Sergio Verardi (IBILCE - UNESP, Sao Jose do Rio Preto,
SP), Marcos Martins (USP/LAL, Bairro Butantan)
This work presents analytical and numerical results for the
pressure field distribution along the axis of tubular
geometries with arbitrary axisymmetric cross sections with
an arbitrary time- and position-dependent gas source.
Several areas of applied physics deal with problems in highvacuum and ultra high-vacuum technology that present
tubular form. In many cases one finds tubes with non
uniform cross sections, like parts of particle accelerators,
colliders, storage rings, gravitational antennas, and electron
devices, like klystrons, electron microscopes, and also parts
of vacuum systems in general, for instance, bellows, conical
pipes and others. In this work one can get the detailed
pressure distribution is not determined. This work presents
and describes in detail the pressure field in tubes with
arbitrary axisymetric cross sections. Details of the
mathematical and physical formulations and modeling
are given; specific conductance and specific throughput
are defined; and a detailed discussion about the
boundary conditions is given. These concepts and
approach are applied to usual realistic cases, like
conical tubes and bellows, with typical laboratory
dimensions.
Ceeteps, Fapesp, Cnpq
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
beam current of 1.5 A. The temperature of corrugation was
about 35&#61616;C and the temperature rise was less than
1/5 of that of a bellows with a conventional finger-type RF
shield. The temperature of the comb teeth was about 50C
while that of fingers of finger-type RF shield was estimated
about 130C for the same HOM power. No vacuum arcing
was detected during the beam operation.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
169-1533 - Vacuum Characterisation of a Woven
Carbon Fiber Cryosorber in Presence of H2
Vincent Baglin, Thomas Garcin (CERN, Geneva)
Some of the cryogenic components in the Large
Hadron Collider (LHC) will operate at 4.5 K. The H2
desorption will rapidly increase to the saturated vapour
pressure, 3 orders of magnitude larger than the design
pressure. Therefore, the use of cryosorbers is
mandatory to provide the required pumping capacity
and pumping speed. The behaviour of a woven carbon
fiber to be used as a cryosorber has been studied under
H2 injection. The pumping speed and capacity
measured in the range 6 to 30 K are described.
Observations made with an electron microscope are
shown. A proposed pumping mechanism and the
implications to the LHC are discussed.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
171-272 - A Practical 500kV Solid State Marx Bank
Modulator
Greg Leyh (SLAC, Menlo Park, California)
Recent advances in high voltage IGBT capabilities have
made possible a range of novel solid-state modulator
concepts that were unthinkable a decade ago. At present,
there are two prototype solid-state modulator designs under
evaluation at SLAC -- A conventional pulse-transformer
design using an 80kV solid-state switch in place of a
thyratron, and an 'induction modulator', which uses a stack
of magnetic cores to couple many paralleled primary
windings to a common secondary winding. Both of these
prototype modulators are currently driving actual klystron
loads at SLAC. Another promising solid-state modulator
concept still in the early stages of development is the Marx
configuration -- where an array of stacked modules
generates high-voltage output pulses directly from a low DC
input supply voltage. This scheme eliminates the large and
costly magnetic cores inherent in the other two designs,
resulting in a considerably simpler and cheaper mechanical
solution. The main disadvantage to this approach is that the
individual Marx sections must float at high voltages,
complicating the distribution of power and timing signals.
Several research groups have produced limited scale Marx
prototypes in recent years. The largest prototype built to
date [DTI] generates an output pulse of approximately
50kV, with plans to eventually move to higher voltage
levels. This paper examines in closer detail the practical
advantages and pitfalls of a solid-state Marx configuration,
and explores a design approach with emphasis on
performance, wall-plug efficiency, cost of manufacture,
availability and ease of service. The paper presents
electrical diagrams, mechanical CAD layout and preliminary
prototype test data.
Work supported by the U.S. Department of Energy under
contract DE-AC03-76SF0051
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
170-1563 - Development of a Bellows with Combtype RF Shield
Yusuke Suetsugu, Kyo Shibata, Mitsuru Shirai (KEK,
Ibaraki)
An all-metal bellows chamber with a comb-type RF
shield inside for a high current accelerator was
developed and tested in the KEK B-factory (KEKB).
The comb-type RF shield has no thin fingers but nested
comb teeth instead at the inner surface. The comb-type
RF-shield has a higher thermal strength structurally
compared to the conventional finger-type one. The
leak of TE mode like HOM through the slits is almost
suppressed. Two test models installed in the positron
ring of KEKB showed good property up to a stored
172-456 - High Voltage Measurements on Nine PFNS for
the LHC Injection Kicker Systems
Michael John Barnes, Gary Dale Wait (TRIUMF,
Vancouver), Laurent Ducimeti&#232;re (CERN, Geneva)
Each of the two LHC injection kicker magnet systems must
produce a kick of 1.3 T.m with a flattop duration variable up
to 7.86 microseconds, and rise and fall times of less than
900 ns and 3 microseconds, respectively. A kicker magnet
system consists of four 5 Ohm transmission line magnets
with matching terminating resistors, four 5 Ohm Pulse
Forming Networks (PFN) and two Resonant Charging
Power Supplies (RCPS). Nine PFNs, together with
associated switch tanks, and dump switch terminating
resistors have been built at TRIUMF and all have been
168-1532 - Gas Condensates onto a LHC Type
Cryogenic Vacuum System Subjected to Electron
Cloud
Vincent Baglin, Berthold Jenninger (CERN, Geneva)
In the Large Hadron Collider (LHC), the gas desorbed
via photon stimulated molecular desorption or electron
stimulated molecular desorption will be physisorbed
onto the beam screen held between 5 and 20 K. Studies
of the effects of the electron cloud onto a LHC type
cryogenic vacuum chamber have been performed with
the cold bore experiment (COLDEX) installed in the
CERN Super Proton Synchrotron (SPS). Experiments
performed with gas condensates such as H2, H2O, CO
and CO2 are described. Implications to the LHC design
and operation are discussed.
Type of presentation requested: Poster
Classification: [T14] Vacuum Technology
tested at high voltage (54 kV) to ensure that the
performance is within specification. This paper
describes the HV measurements, compares these
results with low voltage measurements and analyses
the pulse performance of the PFNs. The measurements
are compared with results from PSpice simulations and
small discrepancies between the predictions and
measurements are explained.
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
173-604 - Solid-state Marx Bank Modulator for the
Next Linear Collider
Michael Kempkes, Floyd Arntz, Jeffrey Casey, Marcel
Gaudreau (Diversified Technologies, Inc., Bedford)
The Next Generation Linear Collider (NLC) will
require hundreds to thousands of pulse modulators to
service more than 3300 klystrons. DTI recently
investigated the use of a solid-state Marx switch
topology for the NLC, and has transitioned this work
into the development of a full-scale, 500 V solid state
Marx system. Combined with recent advances in
semiconductor technology and packaging, these efforts
have moved the performance of the Marx pulser far
ahead of early estimates. The Marx pulser eliminates
the pulse transformer, which is associated with
significant loss of performance and a 15-20% penalty
in the efficiency of a conventional modulator. The
increase in efficiency attributable to the Marx topology
can account for over $100M in power cost savings over
ten years of NLC operation, an amount comparable to
the acquisition costs of the pulsed power systems. In
this paper, DTI will discuss the design and
development of the Marx Bank modulator. Its
performance scales to 125 ns risetime (10-90%) for
either a 500 kV, 265 A pulse (for one klystron), or a
500 kV, 530 A pulse (for two klystrons). The use of a
unique, common mode inductive charging system
allows transfer of filament power without separate
isolation transformers.
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
174-789 - A Highly Stable Kicker Pulser System for
the BESSY FEL Project
Joerg Feikes, Olaf Dressler, Jens Kuszynski (BESSY
GmbH, Berlin)
In the BESSY FEL design a kicker system is forseen to
extract electron bunches from the main LINAC into
two FEL beam lines, beside the straigth main beamline.
Sine half wave pulsers with a repetion rate of up to 1
kHz and modest pulse currents of 120A will be used.
To receive the maximum FEL gain, it is crucial, that
the extracted bunches enter well centered into the
undulators. Hence, the extraction demands for very
high short-term stability of the magnetic field (shot to
shot). A kicker pulse amplitude with a relative
amplitude jitter smaller than 5*10-5 would be tolerable
?more than one order smaller than the jitter of
conventional BESSY II kicker systems in use. A new
highly stable semiconductor based kicker pulser
prototype was designed, built and tested at BESSY. It
was shown that the stability of the pulse current fulfills
the FEL requirements. The pulser design, its layout and the
corresponding pulse current jitter measurements are
presented.
Bundesministerium fuer Bildung und Forschung and the
Land Berlin
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
175-1100 - Measurement of Fast High Voltage Pulse and
High Noisy DC Siganla for Modulator at the PLS Linac
Sung-Chul Kim, Yeung-Jin Han, Sang-Hee Kim, Sang-Hoon
Nam, Soung Soo Park (PAL, Pohang)
The 2.5-GeV electron linac at Pohang accelerator laboratory
(PAL) has been operated continuously as a full energy
injector for the Pohang Light Source (PLS) since Dec. 1994.
There have been continuous efforts to improve the klystronmodulator system more stable and reliable. At pulse
operated modulator system, important pulse and DC signals
are beam voltage, beam current, EOLC current HVDC
voltage and HVDC current. Pulse signals are fast high
voltage pulse 30 Hz, 5ms. These signals are adequate level
down from modulator but including high level switching
noisy. To amplitude measure of these signals for every
trigger signal, we developed special module sampling hold,
A/D, calculating and D/A. The output signals of these
modules are 0 ~ 10 V DC signal and not include any noise
signal. These output signals are connected interlock
interface module of the modulator controller. Therefore
computer system (PC) of the modulator controller is free to
noise of these signals and can precise monitor pulse & noise
DC signal. In these paper, we are described itself
characteristics pulse and high noisy DC signals of the
modulator, signal conditioning technique after noise
elimination and operation status of the modulator controller.
Work supported by the Ministry of Science and Technology,
Korea
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
176-1108 - Operational Analysis of PLS 2-GeV Electron
Linac Klystron-modulator System
Soung Soo Park, Yeung-Jin Han, Sang-Hee Kim, Sung-Chul
Kim, Sang-Hoon Nam (PAL, Pohang)
The klystron-modulator(K&M) system of the Pohang Light
Source(PLS) had been supplying high power microwaves
for the acceleration of 2 GeV electron beams. There are 11
sets of K&M systems to accelerate electron beams to 2 GeV
nominal beam energy without operating one klystronmodulator. One module of the K&M system consists of an
80 MW S-band (2856 MHZ) klystron tube and the matching
200 MW modulator. The total accumulated high-voltage
run-time of the oldest unit among the 12 K&M systems has
reached nearly 68,000 hours as of Dec. 2003 and the
summation of all the units' high voltage run-time is
approximately 820,000 hours. The overall system
availability is well over 95%. There have been continuous
efforts to improve the klystron-modulator system more
stable and reliable. To improve self-diagnostic, operation,
monitoring, and remote communication, we developed a
new modulator controller based on an industrial PC platform
in 2002. In this paper, we are able to review overall system
performance of the high-power K&M system and the
operational characteristics of the klystrons and thyratrons,
and overall system's availability analysis from Jan. to
Dec. 2003.
This work is supported by MOST(Korea Ministry of
Science and Technology) and POSCO(Pohang Steel
and Iron Company)
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
current, 10us pulse width, 364 Watts per coil section, driven
by fast solid state switch with an energy recovery inductor.
Eddy and beam image current losses were ~ 164 watts.
This work was supported by the U.S.Department of Energy
under Contract No. DE-AC03-76SF00098
Type of presentation requested: Poster
Classification: [T16] Pulsed Power Technology
177-1260 - SNS Extraction Fast Kicker Pulsed
Power System
Wu Zhang, Harald Hahn, Jian-Lin Mi, Chien Pai, Jon
Sandberg, Yugang Tan, Nicholaos Tsoupas, Joseph
Tuozzolo, David S. Warburton, Jie Wei (BNL, Upton,
Long Island, New York), Roy I. Cutler, Kenneth R. Rust
(ORNL/SNS, Oak Ridge, Tennessee)
The Spallation Neutron Source (SNS) is a next
generation high intensity beam facility. Its
Accumulator Ring Extraction Fast Kicker System is a
very high peak power, high average power, high
precision pulse-waveform, ultra-low beam impedance,
and high repetition rated pulsed power system. It has
been successfully design and developed at Brookhaven
National Laboratory. This system will consist of
fourteen identical high voltage modulators and fourteen
extraction magnet sections located inside of the SNS
accumulator ring. The overall system output will reach
multiple GW peak power with 60 Pulse-per-second
repetition rates. The techniques of reducing impedance,
improving rise time, and minimizing ripples will be
discussed. The lifetime considerations, issues of the
system design, development and construction are
presented in this paper.
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: Poster
Classification: [T16] Pulsed Power Technology
179-1346 - Operational Experiences with the Spallation
Neutron Source Converter Modulator System
David E. Anderson, Jim D. Hicks, Mark Wezensky
(ORNL/SNS, Oak Ridge, Tennessee), David M. Baca, Robin
F. Gribble, William Reass (LANL, Los Alamos, New
Mexico)
The Spallation Neutron Source (SNS) is a new 1.4 MW, 1
GeV accelerator under construction at ORNL.
The
accelerator requires 15 high voltage converter modulator
(HVCM) systems to drive a variety of pulsed cathode
klystron configurations. Each HVCM unit can produce up
to 140 kV at 11 MW peak, 1.1 MW average power. The
units are 20 kHz polyphase resonant boost inverters. The
HVCMs are supplied by a cast coil transformer unit, feeding
an SCR controller for rectification, regulation, and soft start
functions. A self-clearing capacitor bank supplies three HBridge IGBT transistor networks to generate 20 kHz
transformer primary drive waveforms. Nanocrystalline
cores are utilized for step-up transformers, providing low
core loss and compact design. After rectification and
filtering, pulse widths up to 1.35 ms are achievable. Gate
pulse generation, circuit protection, and personnel safety are
provided by a DSP- and PLC-based control rack. Presently,
2 units at LANL and 6 at ORNL have thousands of
operational hours combined. We will present an overview
of the system design, system optimization tradeoffs, ongoing
development efforts, and performance and operational
considerations.
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: [T16] Pulsed Power Technology
178-1325 - LUX - A Kicker Design for the Rapid
Transfer of the Electron Beam Between Radiator
Beamlines
Gregory D. Stover (LBNL/ALS, Berkeley, California)
I present in this paper preliminary design concepts for
LUX - A ?fast kicker design for rapid transfer of the
electron beam between radiator beamlines. This paper
is a very simple feasibility study to find a rougly
optimized subset of engineering parameters that would
satisfy the initial design specifications of: Pulse width
< 30us, time jitter < 1ns, magnetic length < 0.5meter,
gap hight = 15mm, gap width = 25mm, peak field =
.6Tesla, bend angle = 1.7 deg. for beam energy of 3.1
Gev, repetition rate = 10KHz. An H magnet core
configuration was chosen. Through an iterative
mathematical process a realizable design was chosen.
Peak current, Peak voltages across the coils, conductor
losses due to proximity and skin effects, di/dt rates,
eddy and beam current heating in the ceramic vacuum
chamber, and basic circuit topology were investigated.
Types and losses of core material were only briefly
discussed. The final topology consists of two magnets
in series running at 10KHz, .3Tesla, 630 amp peak
180-678 - The Alignment Jacks of the LHC Cryomagnets
Jishnu Dwivedi, Santosh Giri Goswami, Abhay Kumar, V.
Madhumurthy, Hukum Chand Soni (CAT, Indore (M.P.)),
Vittorio Parma (CERN, Geneva)
The precise alignment of the some 1700 cryomagnets of the
LHC collider, requires the use of some 7000 jacks. The
specific requirements and the need for an cost-effective
solution for this large production, justified the development
and industrialisation of a dedicated mechanical jack which
was developed, and is now being produced, in the
framework of a collaboration between CERN and the Center
for Advanced Technology in India. Three jacks support each
of the 32-ton heavy, 15-meter long cryo-dipoles of LHC,
and provide the required alignment features. The main
requirements are a setting resolution of 0.05 mm, and a
range of movement of 20 mm in the horizontal and 40 mm
in the vertical direction. Each jack has two degrees of
controlled movement in the horizontal and vertical direction,
whereas the remaining horizontal movement is left free. By
a suitable choice of the layout of the three jacks, the
full range of alignment of a cryo-magnet can be
obtained. The design of the jacks evolved from a
preliminary value analysis between various concepts,
towards the complete engineering of the retained
concept, selection of the most appropriate and costeffective industrial production processes and setting-up
of an effective quality assurance policy. Building and
testing of 36 prototype jacks allowed an extensive
experimental validation of their performance at CERN,
where they were operated in the String 2 facility, and
yielded an improved understanding for cost-effective
steering of the production processes before launching
the series production. Presently, the mass production of
the jacks is in progress with two Indian manufacturers,
and some 1500 jacks have already been delivered to
CERN. Considering the successful performance of the
jacks, it is now envisaged to extend the use of the same
type of jacks to provide the even higher-demanding
alignment of the low-beta quadrupoles of LHC.
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
181-769 - Experiences on the Hydrostatic Levelling
System of the SLS
Fuqiang Wei, Leonid Rivkin, Albin Wrulich (PSI,
Villigen)
The Hydrostatic Levelling System (HLS) of the SLS
was installed and commissioned in year 2000. It is a
measurement system for monitoring the vertical
positions of the SLS storage ring girders. It is
integrated in the concept of dynamic alignment. The
HLS was modified and re-calibrated in 2002. Since
January 2003 the system has collected approximately 2
million measurements. The analysis of the data shows
that displacement of the SLS storage ring foundation
and the girder support was in the range of 0.15 mm in
year 2003. The long term HLS stability was
significantly improved. The short term precision of the
HLS is in the micrometer range. The experience gained
on the HLS is presented.
Paul Scherrer Institute
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
182-995 - Characteristics of Ground Motion at KEK
and SPring-8
Yoshinori Nakayama (JPOWER, ), Shigeru Takeda
(KEK, Ibaraki)
Authors
Y. Nakayama, T. Ito, (JPOWER); R.
Sugahara, S. Takeda, H.Yamaoka, M.Yoshioka (KEK);
S.Matsui, C.Zhang (SPring-8); S. Yamashita (ICEPP):
Abstract
Stability of ground is preferable for
accelerator beam operation. We have measured ground
motion of ground at the KEKB and SPring-8 site,
where the ground has quite different characteristics
each other. In this paper, some of analysis results are
shown, and the characteristics of the ground motion at
the KEKB site and those at the Spring-8 site are
compared.
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
183-1110 - Instrumental Uncertainty in Measuring the
Geometry of the LHC Main Dipoles.
Marco La China, Juan Garcia Perez, Giuseppe Gubello,
Walter Scandale (CERN, Geneva)
In the Large Hadron Collider 1232 superconducting dipoles
will bend the two 7 TeV energy beams along a 27 kmcircumference trajectory. The series production (assigned to
three European firms) will require a well-defined procedure
to check, in every magnet, the respect of the dimensional
specifications. To verify the tolerances of few tenths of
millimeter over the 15-meter length in each cold mass, a
laser tracker is necessarily used. To access the two beam
apertures and to increase the measurement accuracies, the
laser tracker is placed in different stations around the dipole
defining a 'multi-station measuring procedure'. The noise
affecting all the data taken so far suggested a careful
analysis of the procedure itself. Through the computer
modeling (based on a Monte Carlo algorithm), the statistical
error was quantified and compared to the experimental error.
From this comparison the critical aspects of low accuracy
rooted in the multi-station procedure were better understood,
allowing the optimization of the procedure itself for the
forthcoming series production.
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
184-1135 - LHC Dipole Axis and Spool Piece Alignment
in Warm and Cold Conditions
Mirco Coccoli, Marta Bajko, Marco Buzio, Juan Garcia
Perez, Beauquis Jerome, Marco La China, Elena Wildner
(CERN, Geneva)
The installation and commissioning of the LHC dipoles
requires the knowledge of the magnetic axis and of the spool
piece corrector alignment at the operating conditions. The
installation is based at present on the use of geometric
information derived from mechanical measurements
performed in warm conditions, with the assumption that the
geometric and magnetic axis are coincident. Any
discrepancies between mechanical and magnetic axis and
unforeseen geometry variations from ambient to cold
operating temperature can introuduce important uncertaintes
in the prediction of the alignment at operational conditions.
Such prediction is studied through correlations between
measurements performed at room and liquid helium
temperature. A statistic analysis of the measurement data
available is presented showing uncertainties on the
correctors alignment. They are compared with beam-based
specifications of the positioning of the spool piece.
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
185-1161 - Structural Analysis for the Unified Model of
Short Straight Section, Service Module, Jumper
Connection and Magnet Interconnect of Large Hadron
Collider of CERN.
Subhajit Dutta, Jishnu Dwivedi, Abhay Kumar, Hukum
Chand Soni (CAT, Indore (M.P.)), Blazej Skoczen (CERN,
Geneva)
The Short Straight Section (SSS) of the Large Hadron
Collider (LHC) houses a twin quadrupole.The cryogens are
fed to the SSS through a Jumper Connection between
service modules of Cryogenic Distribution Line (QRL) and
SSS.A Finite Element analysis has been performed in
collaboration with CERN for the unified model of SSS
of LHC,consisting of cold mass, cold supports,vacuum
vessel and its bellows, interconnects, jumper
connection and alignment jacks. The model has been
developed to understand coupling between the
quadrupole magnet and the service module due to
ground motion and during the realignment or global
smoothening of the LHC arc. The model incorporates
experimental stiffness values for support posts, internal
pipes and jacks and calculated stiffness for magnet-tomagnet interconnects. The computation space and time
has been reduced by executing a two step linear static
analycal approach with an initial trial analytical
approach cycle in which the program estimates the
behavior of the flexibles. A special routine is
developed within ANSYS,using APDL which selects
the correct secant stiffness of flexibles(by applying a
user interactive logical algorithm)from their non-linear
force displacement characteristics.
CERN(European Organization for Nuclear
Research).Geneva
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
186-1224 - Analysis of the Cold Mass Displacements
at the TTF
Angelo Bosotti, Carlo Pagani, Paolo Pierini
(INFN/LASA, Segrate (MI)), Rolf Lange (DESY,
Hamburg), Raffaele De Monte, Mario Ferianis
(Sincrotrone Trieste S.C.p.A., Basovizza, Trieste)
Few of the TTF cryomodules have been equipped with
wire position monitors (WPM) in order to monitor on
line the displacements of the cold mass to verify
alignment stability and reproducibility . Based on the
operation experience of the first prototypical
cryomodules, equipped with up to 36 WPMs
distributed in two strings, on the last generation
cryomodules a single string of 7 sensors has been
installed. Here we review and analyze the data
collected so far to prove that the the proposed
cryomodule design is consistent with the TESLA
alignment requirements.
Type of presentation requested: Poster
Classification: [T17] Alignment and Survey
187-233 - Shielding Design Study for CANDLE
Facility
Khnkanos N. Sanosyan, Mher Aghasyan, Raphael
Mikaelyan (CANDLE, Yerevan), Vartiter Vartanian
(Stanford University, Stanford, Califormia)
The radiation shielding design study for the third
generation synchrotron light source CANDLE is
carried out. The electron beam loss estimates have
done for all the stages from linac to storage ring. A
well-known macroscopic model describing the dose
rate for point losses has been used to calculate the
shielding design requirements of the facility.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
188-625 - The LHC Access Control System
Pierre Ninin, Alisdair Day, Serge Di Luca, Louis
Hammouti, Jean-Francois Juget, Ghislain Roy, Luigi Scibile
(CERN, Geneva)
The LHC complex is divided into a number of zones with
different levels of access controls. Inside the interlocked
areas, the personnel protection is ensured by the LHC
Access System. This system is made of two parts: the LHC
Access Safety System and the LHC Access Control System.
During machine operation, the LHC Access Safety System
ensures the collective protection of the personnel against the
hazards arising from the operation of the accelerator. By
interlocking the LHC key safety elements, it will permit
access to authorised personnel in the underground premises
during the accelerator shutdowns and will deny access
during accelerator operation. On the other hand, the LHC
Access Control System, regulates the access to the
accelerator and the numerous support systems. It allows a
remote, local or automatic operation of the access control
equipment that verifies the users? authorization, identifies
them, locks and unlocks access control equipment and
restricts the number of users working simultaneously in the
interlocked areas. This paper introduces the main functions,
architecture, technologies and methodology used to realise
the LHC Access system.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
189-807 - VDHL Design and Simulation of a Fast Beam
Loss Interlock for TTF2
Abdallah Hamdi (CEA/Saclay, Gif-sur-Yvette), Michel
Luong (CEA/DSM/DAPNIA, Gif-sur-Yvette), Matthias
Werner (DESY, Hamburg)
The TTF2 fast beam loss interlock provides different modes
of protection. Based on the differential beam charge
monitoring over a macropulse, a pulse slice or bunch-bybunch, the signal processing time should be as short as the
bunch repetition period (110 ns). The signal delivered by the
toroid-like inductive current transformer always shows an
envelope droop due to its self-inductance to resistance ratio.
When the macropulse length is comparable to this ratio, the
charge of each bunch must be derived from the difference of
the top to the bottom level on the signal. This necessity
combined to the various protection modes leads to a digital
implementation. All the processing functionalities are
designed with VHDL for a Xilinx FPGA. Because the
interlock involves other control signals in addition to the
toroid signal with specific shapes, which cannot be easily
reproduced for the design validation before the TTF2
completion, VHDL provides meanwhile the possibility for
an exhaustive validation of the system with a software test
bench including all timing information.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
190-964 - Technical and Performance Requirements
for Monitoring of Pulsed, Mixed Radiation Fields
around High Energy Accelerators
Doris Forkel-Wirth, Hans Gregor Menzel, Andre
Muller, Michel Pangallo, Daniel Perrin, Markus
Rettig, Stefan Roesler, Luigi Scibile, Christian Theis,
Helmut Vincke (CERN, Geneva)
Radiation protection survey around CERN's High
Energy Accelerators represents a major technical and
physical challenge due to the pulsed and complexity of
the mixed radiation fields. The fields are composed of
hadrons, leptons and photons ranging in energy from
fractions of eV to several 10 GeV. In preparation of the
implementation of a Radiation Monitoring System for
the Environment and Safety (RAMSES) of the future
Large Hadron Collider (LHC) and its injectors
comprehensive studies were performed to evaluate the
suitability of different existing monitors for this task.
Different ionization chambers were exposed to short,
high-intensity radiation pulses and their saturation
levels for high dose rates determined. Limiting factors
such as recombination effects and the capacity of the
electronics to process a high number of charges within
very short time were studied in detail. These results are
being used to optimize the design of the read-out
electronics. In additional studies, the response of two
different types of ionization chambers to high-energy
radiation was investigated by measurements in the
mixed radiation fields of the CERN EU high-energy
Reference Field (CERF) facility. The results of the
experiments agreed well with calculations, clearly
demonstrating that modern Monte-Carlo simulation
techniques can be used to design radiation monitors
and to optimize their performance.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
191-966 - The LHC Radiation Monitoring System
for the Environment and Safety
Luigi Scibile, Doris Forkel-Wirth, Hans Gregor
Menzel, Daniel Perrin, Gustavo Segura Millan, Pavol
Vojtyla (CERN, Geneva)
A state of the art radiation monitoring and alarm
system is being implemented at CERN for the LHC.
The RAdiation Monitoring System for the
Environment and Safety (RAMSES) comprises about
350 monitors and provides ambient dose equivalent
rates measured in the LHC underground areas as well
as on the surface inside and outside the CERN
perimeter. In addition, it monitors air and water
released from the LHC installations. Although
originally conceived for radiation protection only,
RAMSES also integrates some conventional
environmental measurements such as physical and
chemical parameters of released water and levels of
non-ionizing radiation in the environment. RAMSES
generates local radiation warnings, local alarms as
well as remote alarms on other monitored variables,
which are transmitted to control rooms. It generates
operational interlocks, allows remote supervision of all
measured variables as well as data logging and safe,
long-term archiving for off-line data analysis and
reporting. Requirements of recent national and
international regulations in combination with CERN's
specific technical needs were translated into the RAMSES
specifications. This paper outlines the scope, the
organization, the main system performance and the system
design.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
192-967 - Applicability of IEC-61508 in CERN
Accelerator Safety Infrastructure
Luigi Scibile, Silvia Grau, Pierre Ninin, Rui Nunes (CERN,
Geneva)
This paper presents the experience of setting up the
International Standard IEC-61508 of Functional Safety as a
framework for the CERN European Laboratory of Particle
Physics, in particular in the domain of security, alarm
systems, and radiation monitoring systems. The measures
put in place to follow the management of functional safety,
the associated documentation, the safety lifecycle
requirements, and the functional safety assessment for
Safety Intergity Level 2 systems are described. An
assessment of the applicability of this standard after 4 years
of experience in collaboration with the industry is also
presented.
Type of presentation requested: Poster
Classification: [T18] Radiation Monitoring and Safety
193-286 - Beam-power Calibration System for Industrial
Electron Accelerators
Vyacheslav Uvarov, Sergey Petrovich Karasyov, Valeriy
Ivanovich Nikiforov, Roman Ivanovich Pomatsalyuk,
Valentin Andreevich Shevchenko, Il'ya Nikolaevich
Shlyakhov, Ali Enverovich Tenishev (NSC/KIPT, Kharkov)
Modern electron accelerators for industrial application
provide particle energy of up to 10 MeV and beam power of
up to 100 kW. Such a beam is ejected into an air using a
scanning system. The measuring channel based on a totalabsorption calorimeter of flow-type for a beam calibration
with respect to energy flow is designed. The processes of
beam interaction with the primary measuring converter (a
water-cooled beam absorber of especial geometry) were
previously studied using a computer simulation. The
metering circuit of the channel is made as a stand-alone
module with LCD display and control keypad. It performs
the operations of temperature measurement at the input and
output of the absorber, as well as a water flow-rate
determination. The absorbed power is calculated from
measured parameters and then is displayed and stored into
channel memory using appropriate software. The process is
carried out both in off-line mode and under control of the
external PC via a serial interface of RS-232 type.
Work is supported by STCU under contract # 3151
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
194-376 - Engineering Design of High-current RFQ
Structure with Elliptic Coupling Windows
Daniil Kashinskiy, Andrej Kolomiets, Sergey Minaev,
Vladimir Pershin, Boris Sharkov, Tatyana Tretyakova
(ITEP, Moscow)
Four-vane RFQ structure with elliptic coupling windows has
been originally developed at ITEP for injection into ITEP-
TWAC synchrotron/storage ring complex, being lately
adapted for RIA project too. As the electrodynamics
simulations show, this structure combines the high
efficiency with the operating mode stability against
asymmetric detuning and electrode misalignment. A
considerable reduction of structure diameter due to
coupling windows becomes important for low
frequency range which is necessary for the heavy ion
acceleration. At the same time, the electrode
configuration allows the efficient cooling and high duty
factor operation. A mechanical design of 81 MHz, 1.6
MeV/u, 6 m long heavy ion RFQ section is discussed.
The outer tank is made of two layers, steel and copper,
joined by using the thermal diffusion technology. Each
electrode is supplied with the alignment mechanism
and connected to the tank by the flexible conducting
insert. The whole setup is in manufacturing now.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
195-417 - Design, Construction, and Initial
Operation of the SNS MEBT Chopper System
Robert Hardekopf, Sergey Kurennoy, John Power
(LANL, Los Alamos, New Mexico), Alexander V.
Aleksandrov, David E. Anderson (ORNL/SNS, Oak
Ridge, Tennessee)
The chopper system for the Spallation Neutron Source
(SNS) provides a gap in the beam for clean extraction
from the accumulator ring. It consists of a pre-chopper
in the low-energy beam transport (LEBT) and a faster
chopper in the medium-energy beam transport
(MEBT).
We report here on the final design,
fabrication, installation, and first beam tests of the
MEBT chopper. The traveling-wave deflector is a
meander-line design that matches the propagation of
the deflecting pulse with the velocity of the beam at 2.5
MeV, after the radio-frequency quadrupole (RFQ)
acceleration stage. The pulser uses a series of fastrisetime MOSFET transistors to generate the deflecting
pulses of +- 2.5 kV with rise and fall times of 10 ns.
We describe the design and fabrication of the meander
line and pulsers and report on the first operation during
initial beam tests at SNS.
Office of Science, US Department of Energy
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
196-430 - Long Term Experience with
Demineralized Water Systems Operation
Luigi Pellegrino (INFN/LNF, Frascati (Roma))
During eight years operation of the Dafne water
cooling system we coped with several critical situations
and managed successfully specific upgrades to the
demineralized water system. Here we revise critically
the collected data and the experience gained in the field
of copper corrosion and related water treatment.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
197-461 - New Low-Loss Ferroelectric Materials for
Accelerator Application
Alex Kanareykin, Elisaveta Nenasheva (Euclid Concepts,
LLC, Solon, Ohio), Vyacheslav P. Yakovlev (Omega-P, Inc.,
New Haven, Connecticut)
Ferroelectric ceramics have an electric field-dependent
dielectric permittivity that can be altered by applying a bias
voltage. Ferroelectric ceramics have been widely used
recently in rf communication technologies, radar
applications, etc. Ferroelectrics have unique intrinsic
properties that makes them attractive for high-energy
accelerator applications: very small response time of ~0.01
nsec, considerably high breakdown limit of more than 100
kV/cm, good vacuum properties. Because of these features,
bulk ferroelectrics may be used as active elements of tunable
accelerator structures [*], or in fast, electrically - controlled
switches and phase shifters in pulse compressors or power
distribution circuits of future linear colliders [**]. One of
the most critical requirements for ferroelectric ceramic in
these applications is the dielectric loss factor. In this paper,
the new bulk ferroelectric ceramic is presented. The new
composition shows a loss tangent of 0.004-0.005 at 11 GHz.
The ceramics have high tunability factor: the bias voltage of
50 kV/cm was enough to reduce the permittivity from 500 to
400. The material chemical compound, features of the
technology process, and mechanical and electrical properties
are discussed. It is shown that there is no fundamental
physical limitation in reducing the loss tangent down to
0.001.
US Department of Energy, Division of High Energy Physics
* A. Kanareykin, W. Gai, J. Power, E. Sheinman, and A.
Altmark, AIP Conf. Proc. 647, Melville, N.Y., 2002, p. 565
** V.P. Yakovlev, O.A. Nezhevenko, J.L. Hirshfield, and
A.D. Kanareykin, AIP Conf. Proc. 691, Melville, N.Y.,
2003, p.187
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
198-477 - Technological Challenges for High Brightness
Photo-injectors
Guy Suberlucq (CERN, Geneva)
Many applications, from linear colliders to free-electron
lasers, passing through light sources and many other
electron sources, require high brightness electron beams,
usually produced by photo-injectors. Because certain
parameters of these applications differ by several orders of
magnitude, various solutions were implemented for the
design and construction of the three main parts of the photoinjectors: lasers, photocathodes and guns. This paper
summarizes the different requirements, how they lead to
technological challenges and how R&D programs try to
overcome these challenges. Some examples of state-of-theart parts are presented.
Type of presentation requested: This is an Invited Oral
Presentation
Classification: [T22] Subsystems, Technology and
Components, Other
199-582 - Detecting Failures in Electrical Circuits
Leading to Very Fast Beam Losses in the LHC
Markus Zerlauth, Brennan Goddard, Verena Kain,
Ruediger Schmidt (CERN, Geneva)
Depending on the beam optics, failures in the magnet
powering at locations with large beta functions could
lead to very fast beam losses at the collimators,
possibly within less than 10 turns. Beam loss monitors
would normally detect such losses and trigger a beam
dump. However, the available time for detection with
beam loss monitors before reaching the damage level
of a collimator might not be sufficient, in particular for
beams with few particles in the tails. This has always
been of concern and becomes even more relevant since
very fast losses have been observed recently at HERA.
In this paper, we present particle tracking studies for
the LHC to identify failures on critical magnets. We
propose a fast detection of such failures in the electrical
circuit, either with highly precise hall probes for
current measurement or measurements of the induced
inductive voltage during the current decay. In
combination with a small and simple interlock
electronics such detection system can provide reliable
and fast interlock signals for critical magnets in the
LHC main ring but could also be used to monitor
injection and extraction magnets. Depending on the
properties of the electrical circuit an increase of the
natural time constant of the current decay using a serial
superconducting magnet is also considered.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
200-703 - Hybrid Dry Coolers in Cooling Systems of
High Energy Physics Accelerators
Jens-Peter Jensen, Barbara Conrad, Ullrich Schuetz,
Frank-Reinhard Ullrich, Aldo Wanning (DESY,
Hamburg)
Wet water cooling towers in high energy physics
accelerators are state of the art. The advantages are
robustness, effectiveness and cost-effectiveness. The
return water temperature is lower than the air
temperature due to cooling via evaporation. The
disadvantages are the high water consumption, which
becomes more costly in the future, and the soiling of
the heat exchangers. If the water source is taken from
wells then the drawdown of the ground water level has
to be taken into account. DESY plans to use hybrid dry
coolers for the two future projects: The XFEL linac and
the PETRA 3 synchrotron light source. A hybrid dry
cooler is a combination of a dry air cooler during cold
and moderate seasons and additional wet cooling
during the hot summer season. The cooling surface is
wetted by adding water to increase the cooling
capability by a factor of 250 %. The hybrid dry cooler
saves a lot of water. The water consumption can be
reduced by 70% compared to a wet cooling system.
This contribution presents the auxiliary water
consumption, the requirement of this water and an
estimate of the temperature control behaviour of the
hybrid dry cooling system.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
201-708 - Timekeeping Mechanism at SLS/APS Control
Systems
Babak Kalantari, Timo Korhonen (PSI, Villigen)
Time is one of the most important and critical parameters in
a distributed control and measurement system. It is
especially crucial when we need to interpret correlation of
different archived process variables (PV) during the time.
Advanced Light Source (APS) and Swiss Light Source
(SLS) are using a very similar control system toolkit
(EPICS) and the same mechanism for timekeeping. Many
input/output controllers (IOC) around the accelerator
complex (including beamlines), run under a real-time
operating system, and carry out the controls and data
acquisition. Each IOC is responsible of keeping its own
local time and time-stamps the local PV?s but tightly
synchronized with a central timing IOC. Dedicated timing
hardware and network makes it possible to maintain
synchronous timestamps with real-time clock. In this paper
we describe the principle of this mechanism, its advantages,
our experiences and further improvements.
Paul Scherrer Institute
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
202-726 - Versatile Phase Locked Loop for
Superconducting Cavities Tests
Jean Francois Denis, Michel Luong, Jorge Novo
(CEA/DSM/DAPNIA, Gif-sur-Yvette)
Testing a superconducting cavity without a tuning system in
a vertical cryostat requires a phase locked loop (PLL),
which locks the frequency of the power source to the
resonance frequency of the cavity because of its very narrow
bandwidth and its resonance frequency fluctuation under
external perturbations. Analog PLL?s are widespread for
that purpose. They make use of a mixer and a low-pass filter
as a non-linear phase detector. This non-linearity involves a
phase shifter that has to be adjusted for locking and
achieving the best performances. Their operation prove to be
time consuming and uncomfortable in many circumstances
like multipactor or field emission conditioning of the cavity.
A new design of a semi-digital PLL with a linear phase and
frequency detector is proposed to overcome these
limitations. The operating frequency of such a PLL could
range from tens MHz to few GHz. A prototype is built for
the test bench of SPIRAL 2 quarter-wave cavities at 88
Mhz.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
203-763 - Design of a Full-custom I-Q Modulator with
Low Offset and Gain Errors
Michel Luong, Michel Desmons (CEA/DSM/DAPNIA, Gifsur-Yvette)
The I-Q modulator is a key component in a digital Low
Level RF (LLRF) system for amplitude and phase
feedbacks. Its residual errors in offset or gain have a strong
impact on the dynamic and accuracy of the feedback loops.
For some frequencies, commercial I-Q modulators are
available on the market. But even in that case, these
components are usually designed for broadband
communication purposes, and their performances in
term of residual errors may not fit the strict
requirements on the final amplitude and phase loop
stability. Since LLRF systems for accelerators are
typically narrow-banded, i.e. limited to few MHz, it is
possible to achieve a high directivity and a very
accurate coupling for hybrids, and an excellent
matching for all subcomponents in a fully custom
design. This approach guarantees the lowest residual
errors for an I-Q modulator. The principle for the
design and the process for the optimization are
presented in this paper.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
204-771 - RF Systems for the SPIRAL 2 SC Linac
Marco Di Giacomo, Bernard Ducoudret, JeanFran&#231;ois Leyge, Lorenzo Roupsard (GANIL,
Caen), Jean Francois Denis, Michel Desmons, Michel
Luong, Alban Mosnier (CEA/DSM/DAPNIA, Gif-surYvette)
In the SPIRAL 2 Linac, a 5 mA, CW , Deuteron beam
is accelerated up to 40 MeV, through a normal
conducting RFQ and 26 independent-phase SC quarter
wave resonators, working at 88,05 MHz. Tube and
solid state amplifiers derived from the standard FM
transmitter modules are used while a new digital
control system has been designed for the feed-back and
feed-forward control system. The paper presents the
power and low level systems for both the normal and
superconducting cavities and results of simulations of
the RF system in operating conditions.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
205-833 - Towards a Unified General Purpose CAD
System at CERN
Timo Hakulinen, Christopher Andrews, Bruno Feral,
Per-Olof Friman, Marcel Mottier, Thomas Pettersson,
Charlotte Sorensen, Eric Van Uytvinck (CERN,
Geneva)
Several different CAD systems are in use at CERN
today. Most of the 3D design work for the LHC is
being done using Euclid from MDTVision. For 2D
design work AutoCAD is widely used. Also, various
special design tools exist for tasks such as electrical
design and schematics. Even though LHC design will
be finished with Euclid, it has been clear since several
years that a new 3D CAD system will be needed in the
future. For this reason CERN carried out a comparison
between the currently available 3D CAD software
using a set of selection criteria important for CERN.
The selected system was CATIA from Dassault
together with local data base system SmarTeam. The
aim is to use CATIA as a multi-disciplinary general
purpose CAD tool which could eventually replace
almost all of the other CAD systems at CERN. For this
purpose, CATIA and SmarTeam are being integrated
with the existing CAD utilities and data base systems
developed in-house. Pilot users are using the system for real
designs and the digital mock-up features of CATIA are used
for integration studies of LHC experiments. The feature list
of CATIA and SmarTeam is impressive and experience with
the software has so far been almost exclusively positive.
This is promising for software with which CERN will likely
have to live for the next 20 years or more.
CERN
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
206-957 - Design Criteria and Technology Challenges for
the Undulators of the Future
Hideo Kitamura (RIKEN Spring-8 Harima, Hyogo)
Nowadays, undulators are essential devices for synchrotron
radiation (SR) facilities since they generate a quasimonochromatic radiation with various features, high
brightness , high energy and special polarization
characteristics.
Particularly, demands for high-energy
radiation in the X-ray region have become much stronger in
many research fields. Accordingly, a short-period undulator
design has been developed, because they increase the
number of periods in a unit undulator length and as a
consequence, they generate brilliant synchrotron radiation.
Also, short undulator periodicity enables emission of highenergy photons, and it opens the way for X-ray beamline
operation in medium size synchrotron radiation facilities,
such as SLS, NSLS, PLS, CLS, ALS, SOLEIL, DIAMOND,
SPEAR-III and so on. From the same reason, a short-period
undulator is very attractive for SASE-FEL or ERL facilities,
since it lowers the electron beam energy necessary for X-ray
operation. As a result this design makes a whole facility
design compact and economic. In the talk, I will review the
status of the development on short-period undulators of
various types (in-vacuum, superconducting and cryogenic
types) and describe the future direction.
Type of presentation requested: This is an Invited Oral
Presentation
Classification: [T22] Subsystems, Technology and
Components, Other
207-1015 - Design and Fabrication of Superfluid Helium
Heat Exchanger Tubes for the LHC Superconducting
Magnets
Francesco Bertinelli, Gilles Favre, Frederic Savary (CERN,
Geneva), Eva Boter (CELLS, Bellaterra (Cerdanyola del
Vallès); CERN, Geneva)
The dipole and quadrupole cold masses of the LHC machine
require about 1700 heat exchanger tubes (HET). In
operation the HET carries a two-phase flow of superfluid
helium at sub-atmospheric pressure. The HET consists of an
oxygen-free, seamless copper tube equipped with stainless
steel ends. After an evaluation of different design
alternatives, a design based on the technologies of vacuum
brazing and electron beam welding has been adopted.
Presence of these multiple technologies at CERN and
synergies with the cleaning, handling and transport of other
15-metre components for LHC, motivated CERN to
undertake this series fabrication on site. The raw copper
tubes are procured in Industry, presenting challenging issues
of geometric precision. Organisation of the HET fabrication
includes cryomeasurements to validate cleaning
procedures, characterization of welding procedures,
buckling design by FEA and experimental verification,
quality control during series production. The series
fabrication of these long, multi-technological
components is continuing successfully, respecting the
project?s tight budgetary and planning constraints.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
208-1022 - Development of New Hydrostatic
Levelling Equipment for Large Next Generation
Accelerator
Shigeru Takeda (KEK, Ibaraki)
The Hydrostatic Levelling Systems (HLS) are installed
and commissioned in many laboratories. We have
developed a new type hydrostatic levelling equipment
for the large future accelerator. The designing points
are as followings: (1) use of half filled water level
sensor instead of the usual full filled level sensor, (2)
the capacitive sensor is supported by an invar rod and
(3) use of digitized signal transfer system. These three
points are very important factor to apply the leveling
system to large next generation accelerator in order to
obtain good temperature stability and being free from
the environmental electronic noises. We have obtained
a typical resolution of the equipment as 0.3 micronmeter, though usual HLS shows the value ten times as
much. We are going to show a detailed report about the
system including data obtained.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
209-1030 - Charge Particle Source for Industrial
and Research Accelerators Operating at the Poor
Vacuum Conditions
Eugeni Olegovich Popov, Andrey Andreevich
Pashkevich, Sergey Olegovich Popov, Andrey
Vladimirovich Vitugov (IOFFE, St. Petersburg)
We investigated the original method of fabrication of
the great number of emitting tips by pulling liquid
metal through the holes in track membrane under
influence of electric field. The track membranes are
produced by cyclotron of Physicotechnical Institute.
This method enables to fabricate up to 1e8 emitting tips
per square cm. Special test facility to investigate
emitter parameters operating at different values of
background residual gas pressure was designed and
developed. The liquid metal multiple tip field emitters
possess some unique characteristics which are
attractive in accelerators for material irradiation:
unlimited life expectancy, large current densities (about
100 mA per sq. cm), practically unlimited surface,
stable emission in poor vacuum.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
210-1129 - Physical Design of the 571.2MHz Subharmonic Buncher
Shilun Pei, Zheqiao Geng, Pengda Gu, Shu-hong Wang
(IHEP Beijing, Beijing)
This paper presented the physical design method of the
571.2MHz sub-harmonic buncher. The two-dimensional
finite difference method software-Superfish and the threedimensional finite integration method software-MAFIA
have been used to simulate the structure of the sub-harmonic
buncher. Both of the simulation results are in good
consistency with the design data. In addition, the
characteristics in the RF cavity simulation with the two
softwares are compared.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
211-1152 - A High Precision Mechanical Tuning System
for Quarter Wave Resonators
Alberto Facco, Enzo Bissiato, Stefania Canella, Davide
Carlucci, Michele Lollo, Davide Zenere (INFN/LNL,
Legnaro, Padova), Vladimir Zviagintsev (TRIUMF,
Vancouver)
The use of high-Q and small rf bandwidth superconducting
quarter wave resonators made of bulk niobium put severe
requirements to the helium bath pressure stability to avoid
cavity detuning. This is not always possible, and cavity
detuning caused by slow pressure changes must be precisely
followed by the cavity tuner. The LNL philosophy is based
on mechanical damping of cavity vibrations and mechanical
tuning in feedback for slow frequency compensation. The
old-fashioned tuners installed in the ALPI linac had
significant performance limitations. To replace them, we
have designed, constructed and tested a new tuner which
integrates the LNL system and control with the TRIUMF,
backlash-free tuner leverage design. The new tuner is
designed to compensate pressure changes up to 100
mbar/minute with a precision of 0.5 Hz, and it will be
installed in the ALPI resonators. An upgraded prototype for
future applications includes a piezoelectric actuator for fast
tuning. Tuner characteristics and first test results will be
presented. This system is extendable to other low-beta
cavity types like superconducting rfqs.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
212-1244 - Low Emittance Beam Generation using a
GV/m High Filed
Katsushi Hasegawa (GUAS/AS, Ibaraki), Hitoshi Hayano
(KEK, Ibaraki)
A low emittance electron beam generation is planned by
using a short pulsed high electric field. Pulsed voltage which
is enough short time duration to avoid electric breakdown
but longer than bunch length is applied to electron gun
diode. High voltage diode can solve the issues on
minimization of emittance growth and space charge effects
which are the problems in RF gun beam. For an estimation
of the beam emittance generated by the diode, a simulation
is performed by using the general particle tracer (GPT) code
in combination with the POISSON code, which calculates
the field map of the diode. And the generation of beam and
measurement of emittance are planned. Simulation
results and experiment status are presented in this
paper.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
213-1259 - LHC Reference Database : Towards a
Mechanical, Optical and Electrical Layout
Database
Pascal Le Roux, Samy Chemli, Antonio Jimeno Yepes,
Bernard Maire, Herve Prin, Antonio VergaraFern&#225;ndez, Markus Zerlauth (CERN, Geneva)
The LHC project has entered a phase of integration and
installation of thousands of diverse components. The
Hardware Commissioning work has also started.
Collecting and distributing reliable and coherent
information on the equipments and their layout
becomes a crucial requirement in the lifecycle of the
project. Existing database tools had to evolve to a more
generic model to cover not only optical layout, but also
the mechanical and the electrical aspects. This paper
explains the requirements, the implementation and the
benefits of this new database model.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
214-1364 - Using the PBO LAB? Optimisation and
Transport Modules to Gain an Improved
Understanding of the LLUMC Proton Therapy
Beamlines
George H. Gillespie, Olga V. Voronkova (G.H.
Gillespie Associates, Inc., Del Mar, California),
George Coutrakon, Jeff Hubbard, Ed Sanders
(LLU/MC, Loma Linda, California)
The Particle Beam Optics Laboratory (PBO Lab) has
an advanced Optimization Module that works in
concert with beam optics codes (also modules in PBO
Lab) to solve optimization and fitting problems that are
difficult or impossible to address with optics code
alone. The PBO Lab Optimization Module has been
used in conjunction with the TRANSPORT Module to
study the beamlines of the proton therapy center at the
Loma Linda University Medical Center (LLUMC).
The primary goal of the study was to establish a fast,
efficient and reliable procedure for determining the
parameters of the beam extracted from the synchrotron
accelerator that best fit the extensive wire scanner
profile data used to monitor the LLUMC proton
therapy beamlines. This paper summarizes how the
PBO Lab Optimization Module is applied to this
problem and presents selected results from the LLUMC
proton therapy beamline study.
G. H. Gillespie Assoicates, Inc. Independent Research
and Development and the Loma Linda University
Medical Center
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
215-1437 - Design & Handling of High Activity
Collimators on the SNS
Graeme R Murdoch (ORNL/SNS, Oak Ridge, Tennessee)
Design & Handling of High Activity Collimators on the
SNS*G Murdoch,S Henderson, K Potter,T Roseberry,Oak
Ridge National Laboratory, USA,H Ludewig, N Simos,
Brookhaven National Laboratory, USAJ Hirst, Rutherford
Appleton Laboratory,UK, The Spallation Neutron Source
accelerator systems will provide a 1GeV, 1.44MW proton
beam to a liquid mercury target for neutron production. The
expected highest doses to components are in the collimator
regions. This paper presents the mechanical engineering
design of a typical collimator highlighting the design
features incorporated to assist with removal once it is
activated. These features include shielding and lifting
fixtures but more importantly a double contained flexible
water system incorporating remote water couplings.Also
presented is a mechanism that allows axial removal of
vacuum bellows and its associated vacuum clamps.*SNS is
managed by UT-Battelle, LLC, under contract DE-AC0500OR22725 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: [T22] Subsystems, Technology and
Components, Other
216-1459 - Control Environment for the
Superconducting Insertion devices at NSRRC
Jenny Chen, Cheng-Kuo Chang, Kuo-Tung Hsu, Kuo Hwa
Hu, Ching-Shiang Hwang, Changhor Kuo, C.J. Wang
(NSRRC, Hsinchu)
To enhance hard X-ray capability in the 1.5 GeV storage
ring of NSRRC to serve the rapidly growing X-ray user
community in Taiwan, the storage ring was installed two
superconducting
insertion
devices.
Three
more
superconducting insertion devices are in planning. A 6 Tesla
superconducting wavelength shifter was installed in mid2002. A 3.2 Tesla superconducting multi-pole wiggler was
installed in December of 2003. Control system and
operation environment have been set up to support the
operation of the superconducting insertion devices. The
implementation and operation experiences will be
summarized in this report.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
217-1503 - Connection Cryostats for LHC Dispersion
Suppressors
Sebastien Marque, Thierry Colombet, Michel Genet, Blazej
Skoczen (CERN, Geneva)
The lattice of the Large Hadron Collider (LHC) being built
at CERN is based on 8 standard arcs of 2.8 km length. Each
arc is bounded on either side by Dispersion Suppressors
connected to the arc by connection cryostats providing 15m
long drift spaces. As for a dipole magnet, the connection
cryostat provides a continuity of beam and insulation
vacuum, electrical powering, cryogenic circuits, thermal and
radiation shielding. In total 16 modules will be constructed.
The stringent functional specification has led to various
analyses. Among them, a light mechanical structure has
been developed to obtain a stiffness comparable to a
dipole magnet, for alignment purpose. Thermal studies,
included lambda front propagation, have been
performed to ensure a cooling time down to 1.9K
within the time budget. A special cooling scheme
around the beam tubes has been chosen to cope with
heat loads produced during operation. We will report
on the general design of the module and on the
manufacturing process adopted to guarantee the tight
alignment of the beam tubes once the module installed
in the machine. Special emphasis will be given on
thermo-mechanical analysis, lambda front propagation
and on beam-tubes cooling scheme.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
218-1538 - SPIRAL 2 RFQ Design
Robin Ferdinand, G&#233;rard Congretel, Aline
Curtoni, Olivier Delferriere, Alain France, Didier
Leboeuf, Jean Thinel, Jean-Christian Toussaint
(CEA/DSM/DAPNIA, Gif-sur-Yvette), Marco Di
Giacomo (GANIL, Caen)
The SPIRAL2 RFQ is designed to accelerate at 88MHz
two kinds of charge-over-mass ratio, Q/A, particles.
The proposed injector can accelerate a 5 mA deuteron
beam (Q/A=1/2) or a 1 mA particles beam with
q/A=1/3 up to 0.75 MeV/A. It is a CW machine which
has to show stable operation, provide the request
availability, have the minimum losses in order to
minimize the activation constraints and show the best
quality/cost ratio. It will be a 4-vane RFQ type, with a
mechanical assembly, the global assumption being to
build an RFQ without any brazing step. Extensive
modelisation was made to ensure a good vane position
under RF. A 1-m long hot model prototype is under
construction in order to validate the manufacturing
concept.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
219-1539 - Towards an Ontology Based Search
Mechanism for the EDMS at CERN
Antonio Jimeno Yepes, Bertrand Rousseau (CERN,
Geneva), Melanie Hilario (DPNC, Genève)
CERN is building its new accelerator, the LHC. All the
data flow generated during its lifecycle is stored in the
EDMS (Engineering Data Management System)
developed at CERN. For such a system it is
compulsory to have a performant search mechanism to
guarantee that the involved people gets the data at the
required time. Due to the size of the collection and the
diversity of people, organizations, divisions . To
overcome this problem, an approach based on a handcrafted domain specific ontology has been tested in
order to improve the information retrieval task within
the technical documentation for the LHC Equipment
Catalog. The experiments have shown that using the
ontology an improvement on the base line has been
produced and encorages IE techniques to refine the
base ontology.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
220-1542 - Layout Drawings of the LHC Collider
Samy Chemli, Bernard Maire, Yvon Muttoni, Antonio
Vergara-Fern&#225;ndez (CERN, Geneva), Alexei
Kournossenko, Rashid Zalyalov (IHEP Protvino, Protvino,
Moscow Region)
The team in charge of the LHC integration largely uses 3D
scenes combining functional positions of equipments and
the 3D CAD model issued from the Cern Drawing Directory
(CDD) repository. This is made possible through the Digital
Mock-Up tool developed at CERN. Giving dimensions in
3D context is a challenge with the current 3D CAD tools
used at CERN. Requirements from users groups have made
clear a need for automatic production of 2D layout
drawings. This paper presents the retained solution to create
on-request dimensioned drawings, to publish them, while
maintaining coherence and consistency with the 3D
integration scenes. Reliability of the information, on-line
availability of the latest layout changes on dimensions and
positions of equipments, and the maintenance of the facility
will also be described.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
221-1564 - Radiation Damage in Magnets for Undulators
at Low Temperature
Teruhiko Bizen (JASRI/SPring-8, Hyogo), Dong Eon Kim,
Hee-Seock Lee (PAL, Pohang), Hideo Kitamura (RIKEN
Spring-8 Harima, Hyogo)
Nd2Fe14B permanent magnets are used in many insertion
devices for its good magnetic and mechanical properties.
However, the radiation sensitivity of the magnets would be
concern when they are used in a strong radiation
environment. It is known that these magnets with very high
coercivity show high resistance to radiation, though the
substance for increasing the coercivity decrease the
remanence. The coercivity and remanence of this magnet
exhibit negative dependence against temperature, so it is
expected to these magnets to show high remanence and high
resistance to radiation at low temperature. The idea of using
magnets at low temperature leads the new concept of the
cryogenic undulators. In this report, the experimental results
of the radiation damage of permanent magnets at low
temperature are shown.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
222-1623 - Mechanical Dynamic Load of the LHC Arc
Cryo-magnets during the LHC Installation
Ofelia Capatina, Kurt Artoos, Gilles Huet, Bertrand
Nicquevert (CERN, Geneva)
About 1700 LHC main superconducting dipoles and
quadrupoles will have to be transported and handled
between the assembly, the magnet measurements and the
storage that precedes the final installation in the LHC
tunnel. To ensure the required mechanic and geometric
integrity of the cryo-magnets, transport specifications and
allowed acceleration loads were defined after detailed
dynamic analysis. A large number of cryo-magnets are
now arriving at CERN on a regular basis. The logistics
for the handling and transport are monitored with triaxial acceleration monitoring devices that are installed
on each cryo-magnet. Measurements are made to
commission new equipment like overhead cranes,
tunnel transport and handling devices to guarantee that
the defined acceleration limits are respected. The
results from the acceleration monitoring that are stored
in the same quality assurance system as the cryomagnets allowed to give a first idea of the level of the
mechanical dynamic load on each magnet throughout
the logistics chain and were used to detect details such
as out-of-specification accelerations that needed
improvement.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
223-1624 - Transport and Installation of Cryomagnets in CERN's Large Hadron Collider Tunnel
Keith Kershaw, Kurt Artoos, Ofelia Capatina, Andre
Yvon Coin, Maurice Gielen, Claude Hauviller (CERN,
Geneva)
The arcs of the Large Hadron Collider (LHC) will
contain around 1700 main superconducting dipoles and
quadrupoles. The long and heavy magnets are
supported on fragile composite support posts inside a
cryostat to reduce the heat in-leak to the magnets' super
fluid helium bath. The presence of fragile components
and the need to avoid geometry changes make the cryomagnets very difficult to handle and transport. The
transport and installation of the LHC cryo-magnets in
the LEP tunnels originally designed for smaller, lighter
LEP magnets has required development of completely
new handling solutions. The paper explains the
constraints imposed by the cryo-magnet characteristics,
the existing tunnel infrastructure and schedule
considerations. The development and realisation of
transport and handling solutions are described, starting
from conceptual design, through manufacture and
testing to the installation of the first cryo-magnet.
Integration studies to verify and reserve space needed
for manoeuvre and the preparation of the infrastructure
for transport and installation operations are also
presented. The paper includes conclusions and some of
the lessons learned.
CERN
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
224-1625 - Installation of A Particle Accelerator:
from Theory to Practice. The LHC Example.
Claude Hauviller, Sylvain Weisz (CERN, Geneva)
Installing and commissioning the thousands of
equipments constituting a Particle Accelerator is a
lengthy and complex process. A large number of
multidisciplinary teams are involved over a long period
lasting usually many years. Diverse boundary
constrains must be taken into account: space, a long
and narrow tunnel with few accesses, time, with
milestones set many years in advance, and obviously
budget. A strict organisation associated with the
management tools and the right people is the only way to
arrive to a success. The keywords are: Knowledge: A unique
and up-to-date database of all the elements and their
location, Integration: Study the physical position of the
elements, suppress the interferences and define the
installation methodology, Prevision: Schedule all the
activities and update on-line, In-situ management and
supervision: Teams dedicated to follow-up, corrective
actions and orphan jobs, Safety. After presenting the
planned overall organization, the paper will present practical
achievements with the example of the LHC machine
installation.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
225-1626 - Installation of the LHC Experimental
Insertions
Sonia Bartolome-Jimenez, Gilbert Trinquart (CERN,
Geneva)
The installation of the LHC experimental insertions, and
particularly the installation of the low-beta quadrupoles,
raises many technical challenges due to the stringent
alignment specifications and to the difficulty of access in
very confined areas. The compact layout with many lattice
elements,
vacuum
components,
beam
control
instrumentations and the presence of shielding does not
allow for any improvisation in the installation procedure.
This paper reviews all the constraints that need to be taken
into account when installing the experimental insertions. It
describes the chronological sequence of installation and
discusses the technical solutions that have been retained.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
226-1627 - Logistics of LHC Cryodipoles: from
Simulation to Storage Management
Katy Foraz, Bertrand Nicquevert, Davide Tommasini
(CERN, Geneva)
The particles traveling in the Large Hadron Collider are
guided by superconducting magnets. The main magnets
(cryodipoles) are 16 m long, 30 tons objects placed with
accuracies of few tenths of mm and therefore imposing
challenging requirements for handling and transportation.
Numerous contracts are constraining the production and
installation of these cryodipoles. These contracts have been
rated according to the baseline schedule, based on a "just in
time" scheme. However the complexity of the construction
and the time required to fully test the cryodipoles before
installation in the LHC required to decouple as much as
possible each contract from the others' evolutions and
imposed temporary storage between different assembly and
test steps. Therefore a tool simulating the logistics was
created in order to determine the number of cryodipoles to
store at the various stages of their production. In this paper
the organization of cryodipole flow and the main challenges
of logistics are analyzed on the basis of the planning of each
main step before installation. Finally the solutions
implemented for storage, handling and transportation are
presented and discussed.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
227-1628 - Planning and Logistics Issues of the LHC
Injection Lines
Luisella Lari, Hubert Gaillard, Volker Mertens (CERN,
Geneva)
The installation of the two LHC injection lines has to
fit within tight milestones of the LHC project and of
CERN?s accelerator activity in general. For instance,
the transfer line from the SPS to LHC point 8 (to fill
the anti-clockwise LHC ring) should be tested with
beam before the end of 2004 since the SPS will not run
in 2005. It will first serve during the LHC sector test in
2006. Time constraints are also very strong on the
installation of the transfer line from the SPS to LHC
point 2 (for the clockwise LHC ring): its tunnel is the
sole access for the LHC cryo-magnets and a large part
of the beam line can only be installed once practically
all LHC cryo-magnets are in place. Of course, the line
must be operational when the LHC starts. This paper
presents the various constraints and how they are taken
into account for the logistics and installation planning
of the LHC injection lines.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
228-1629 - Transport and Handling of LHC
Components: a Permanent Challenge
Caterina Bertone, Ingo Ruehl (CERN, Geneva)
The LHC project, collider and experiments, is an
assembly of thousands of elements, large or small,
heavy or light, fragile. Every one of those has own
transport requirements that constituting for us a real
challenge to handle. The manoeuvres could be simple,
but the complex environment and narrow underground
spaces may lead to difficulties in integration, routing
and execution. Examples of transport and handling of
typical LHC elements will be detailed: the 17m long,
35t heavy but fragile cryomagnets from the surface to
the final destination in the tunnel, the delicate
cryogenic cold-boxes down to pits and detector
components. This challenge did not only require a lot
of imagination but also the close cooperation between
all involved parties, in particular with colleagues from
safety, cryogenics, civil engineering, integration and
logistics.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
229-1630 - Scheduling the Installation of the Large
Hadron Collider
Sylvain Weisz, Katy Foraz, Hubert Gaillard, Luisella
Lari (CERN, Geneva)
The size and complexity of the LHC project at CERN
calls for a strong co-ordination of all installation
activities. The detailed installation planning has to take
into account many constraints such as the component
production rates, the installation contracts or the
transport and handling requirements in a narrow tunnel
with limited access points. The planning also needs to be
flexible enough to cope with aleas that are unavoidable in
such a large project that spans over many years. This paper
describes the methodology followed by the team responsible
for the planning and logistics in order to stay reactive to the
actual progress of the installation and to keep optimizing the
usage of resources.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
230-1682 - A J2EE Solution for CERN's Technical
Infrastructure Monitoring
Peter Sollander, Jan Stowisek (CERN, Geneva)
The Technical Infrastructure Monitoring project (TIM) will
design and implement the future control system for CERN's
technical infrastructure. The control system will be built
using standard components including industrial PLCs, Java
Enterprise Edition (J2EE) including Enterprise Java Beans
and the Java Message Service and relational databases. This
paper describes how these standard technologies are used to
build a flexible, scalable, robust and reliable control system.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other
231-1703 - Recent Developments and New Applications
of Ultra-thin Diamond-like Carbon Target Foils
Vitaly Liechtenstein, Tamara Ivkova (RRC Kurchatov
Inst./INF, Moscow), Manfred Friedrich (FZR, Dresden),
Roland Repnow, Robert von Hahn (MPI-K, Heidelberg),
Eugene Olshanski (RRC Kurchatov Institute, Moscow),
Robin Golser, Walter Kutschera, Alfred Priller
In previous experiments, diamond-like carbon (DLC) foils
which are being produced at Kurchatov Institute, have
proven best suited as long-lived stripper foils for high
energy heavy ion tandem accelerators and ultra-thin
secondary-electron (SE) emitting foils for TOF
spectrometers. This talk will survey the recent advances in
DLC targetry with main emphasis given to development and
applications of ultra thin foils (maximum diameter up to
70mm) with high uniformity and minimal possible effective
thickness of 0.5ug/cm2 for ToF spectrometry Results of
energy loss and multiple scattering measurements for heavy
ions penetrating through the ultra-thin DLC foils will be
presented to give an insight into the optimum design and
performance of relevant ToF systems. Comparative lifetimes
of DLC stripper foils irradiated with high intensity He+
beams at 2 MeV are reported, which demonstrate the
favorable use of DLC foils as supplemental strippers at
RFQ linacs. In conclusion, the attractive results of
application of ultra-thin DLC foils to TOF detectors for
heavy ion AMS as well as to compact tandem accelerators
will be presented.
Type of presentation requested: Poster
Classification: [T22] Subsystems, Technology and
Components, Other