FAIR Requirements for Tune Determination
P.Forck1,G.Franchetti1,V.Kornilov1,P.Kowina1,J.Dietrich2 for the FAIR Team
1GSI,
Darmstadt and 2FZJ, Jülich
 Brief overview of Faclity for Antiproton and Ion Research
 Demands and boundaries for tune diagnostics
Research area:
 Nuclear physics with RIB
 Baryonic matter: ions 30 GeV/u
 Hadrons physics with pbar
 Atomic, plasma, bio physics
Challenges for accelerators:
 High beam intensities
 Beam cooling
 Versatile accelerator facility
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
The FAIR Facility
UNILAC & SIS18 as injector for ions after upgrade
p-LINAC: high current 70 mA, 70 MeV
SIS100: 100Tm, s-c magnets 2T, 1-10 GeV/u
fast ramping 3 T/s, length 1084 m
design: p 4*1013, U28+ 5*1011
SIS300: 300Tm, stretcher or accel.
up to 30 GeV/u, 1T/s
CR:
stochastic cooling
of RIB and pbar
RESR: accumulation of pbar,
deceleration of RIB, 1 T/s
NESR: versatile experimental ring
for stable, RIB, pbar
e-cooling, gas-target, e-A collider
HESR: acc. of pbar to max. 14 GeV,
pellet target, stochastic & e-cooling
HEBT: for fast & slow extraction and low & high currents.
Status: Funding of most parts recently achieved!
pbar
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 Lattice of p and U28+ operation (Design Ions)
Different tunes are required for ions fast / slow extraction and p operation:
 Large acceptance, low dispersion for bunch compression, high γt, flexible lattice settings
 Long section for rf-cavities etc. for 3T/s acceleration, collimators for ionization loss
Ions, fast extr.
U 28+ : 0.2  2 maximal
Energy [GeV]
Tune
Ions, slow extr.
h/v
Max. dispersion -D [m]
protons
229
18.84 / 18.73
17.30 / 17.42
20.84 / 20.73
1.73
1.44
1.30
Max. β–function [m]
h/v
19.6 / 19.6
19.8 / 19.6
20.4 / 19.9
Natural chomaticity ξ
h/v
-1.19 / -1.20
-1.16 / -1.16
-1.25 / -1.26
Design injected emittance ε
h/v
U28+ : 35 / 15
Design injected Δp/p
h/v
U28+ : 0.5 ‰
0.2 ‰
x: 80 mm
y: 40 mm
1/6 of SIS100: Length 181 m
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 Dynamic Aperture Calculation for fast Extraction Mode
Dynamic Aperture uses multipole-coeff. of 96 super-ferric Nucletron dipoles and quadrupoles
(Not included: persitive currents, power supplier ripples, longitudinal coupling)
Example design ion: U28+ at 200 MeV/u injection energy
4 injected batches, 2 bunches each, 1 s max. storage = 1.1∙106 turns
Result: DA ≈ 3∙σ only at injection, ≈ 4.5∙σ at extraction
Lattice nonlinearities contributing
Comparable results for slow extraction and proton working points
→ Stabilization of (bare) tune within Q0≈ 0.01
DA for statically distributed
dipole and quad errors:

P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 Dynamic Aperture Calculation: Space Charge Effect
Due to the 4-fold batch filling the beam with ΔQ ≈ 0.3 is stored up to 1 s.
DA calculations and beam loss for bunched beams:
 Periodic resonance crossing by synchrotron oscillations
: coexistence of stable & unstable regions in phase space
 Decrease of dynamic aperture, losses in % region

Experiments
at CERN and
SIS18 ongoing
Addition problem: vacuum pressure increase by chemical desorption at vessel surface
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Heavy Ions: Beam Loss due to Electron Stripping
At 200 MeV/u electron stripping U28+ U29+ dominates the lifetime:
 Energy loss at surface  desoption  vacuum pressure increase: ‘vacuum instability’
 Optimized lattice with high efficient collimators behind dipoles, efficiency  90%
Demonstration:
‘vacuum instability’ at SIS18
for 7 MeV/u U28+:
Dipole
Yellow: U28+
Red: U29+
Collimator + strong pumping
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 Filling and Acceleration: Design Ion U28+
Injection: 2 bunches at 4 batches, 200 MeV/u for U28+
1. 1 s storage β=0.5, long bunches to reduce tune spread
2. Acceleration within 300 ms up to β=0.95
3. For fast extraction:
barrier-bucket formation + bunch rotation
Demands for tune measurement and feedback:
 variable rf, long bunches during accumulation and prior to compression, large ΔQ
 Fast ramping  reaction time of possible feedback: 10 ms desired  Is this possible?
 Accuracy: only Q00.01 due to tune spread and chromaticity about -1 (uncorrected)
Action
time
GeV/u
bunches
Bf
Ion/bunch
Δp/p ‰ ΔQ
Remark
Accumulation
1s
0.2
8, h=10
0.4
5∙1010
1
-0.3
Sine wave
Acceleration
0.5 s
1.5
8, h=10
0.3
5∙1010
1.5
-0.05
Sine wave
Pre-compression
0.1 s
1.5
1
0.7
5∙1011
0.2
-0.02
Barrier bucket
At compression
0.1ms 1.5
1, h=2
0.05 5∙1011
5
-1
Rotated to 60 ns
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Bunch Compression in SIS100 and Injection to Storage Rings
Acceleration
Short pulses 25 to 60 ns for low emittance of RIB and pbar
SIS100: maximal ΔQ  1 during bunch rotation
SIS100 circumference
Target
Barrier bucket
 2.5 %
Moving barriers
bunch rotation
 0.75 %
50 ns
adiabatic debunching
Pre-compression
Rotated bunch
 0.5 %
Collector Ring CR:
 bunch rotation
 adiabatic de-bunching
 stochastic cooling e.g. 10 s for pbar
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Storage Ring Complex
from SIS18 SIS100,
RIB at 740 MeV/u,
pbar at 3 GeV
Collector Ring CR
fixed rigidity
bunch rotation
stochastic cooling
isochronous mode RIB
Storage time < 10 s
RESR
1011 pbar accumulation
stochastic cooling
fast RIB/pbar deceleration
Storage time up to 1 h
The Storage Rings design:
 normal conducting magnets
 stable ions, RIBs and pbar operation
 13 Tm maximal, versatile modes
 circumference  200 m
 stochastic and electron cooling
 deceleration: RESR, NESR down to 4 MeV/u
 tune: between 2 and 4
atomic physics
HITRAP, FLAIR
Electron ring
NESR
e--cooling
deceleration
RIB experiments
Atomic physics
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
RIBs and Antiprotons at CR and RESR
CR RIB: fixed energy 740 MeV/u
Lifetime measurement, stochastic cooling 1.5 s
CR pbar: fixed energy 3 GeV/u
Stochastic cooling within 10 s
RESR RIB: deceleration
RESR: pbar: accumulation with stochastic cooling
Tune measurement: partly dc-beam  Schottky
Tune feedback: NOT required during cooling
But for 1 s deceleration to prevent for losses
CR
RIB
Length
CR
pbar
RESR
RIB
215 m
RESR
pbar
CR
RESR
248 m
Energy MeV/u 740
3000
740100 3000100
Qx / Q y
4.42/4.24
3.17/3.18 3.85/3.31
3.85/3.31
Trans.Acept.
200
240
1.5
5
Long. Acept.
1.7%
3.0%
0.1%
0.1%
RESR
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
NESR: Versatile Storage Ring for Physics Experiments
Ions operation with RIB and stable ions:
 Storage and cooling for 740  4 MeV/u
 Deceleration 1 T/s maximal
 Experiments with internal targets
Slow and fast extraction after deceleration
pbar:
 Deceleration 1 T/s max down to 30 MeV
 Electron cooling at top and intermediate energy
Deceleration: Tune feedback to prevent for losses
At storage: dc-beams  Schottky better suited
No tune feedback during cooling,
otherwise two active systems
Length
Energy
MeV/u
222 m
RIB: 740  4
Pbar: 3000  30
Tune h/v
3.19/1.86
Momentum accept.
1.5 %
Trans. Accept.
160/4010-6 m
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Antiproton Storage Ring HESR
pbar collisions with proton for hadron spectroscopy
Acceleration from 3 to 14 GeV or deceleration to 1 GeV
# of pbar: 1010 for Δp/p=4∙10-5 for high resolution
1011 for Δp/p=1∙10-4 for high luminosity
Collision with dense pellet target  strong cooling:
stochastic cooling, e-cooling up to 8.9 GeV
Beam manipulation: debunching  cooling  acceleration
deceleration of residual pbar for filling
Tune measurement: Schottky during cooling
Tune feedback: during (slow) acceleration
Length
574 m
Injection energy 3 GeV
Final energy
0.8 – 14 GeV
Rigidity
50 Tm, n-c
Ramp rate
0.1 T/s
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Conclusion
Challenges and questions for tune measurement and feedback:
1. High current synchrotron super-conducting SIS100 (and SIS18 & SIS300)
 Precaution: well working closed orbit feedback (not in operation at SIS18, yet)
 Non-relativistic velocity e.g. U28+: β=0.5 → 0.95 ⇔ 10th harmonic rf 1.1 → 2.2 MHz
 Varying bunching factor during acceleration, barrier bucket… → varying signal amplitude
 Fast ramp within 300 ms → reaction time ≈10 ms desirable: Is this possible ?
 But: Accuracy of ΔQ0≈ 0.01 seems to be sufficient (due to ξ ≈ -1, large Q-spread….)
 Coherent excitation for Q measurement: What is determined for beams with large ΔQ?
 different ions on pulse-to-pulse  remote controlled operation
→ Idea: Using ‘base-band’ bunch recording with 125 MSa/s and digital signal processing
for tune measurement → see talk of Udo Rauch
2. Normal-conducting storage rings:
Tune measurement (constant energy) for varying number of ions → large dynamic range
Tune feedback during deceleration (to low rigidity) to prevent for particle loss (n.c. magnets)
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 dynamic aperture calculation: After acceleration
At upper flat-top the dynamic aperture is sufficient
For fast extraction: barrier bucket creation and bunch rotation at h=1
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 dynamic aperture calculation: Slow extraction
At injection 200 MeV/u U28+:
Slow extraction:
Different working points
Qx = 17.42  17.32
Qy = 17.35  17.3
to fulfill Hard-condition
At extraction 1.5 GeV/u U28+:
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS100 dynamic aperture calculation: Proton injection
Proton working point Qx = 21.85 and Qy=21.79
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Radio-Frequency Systems: Overview
Rf-System
Total P
f [MHz]
#
Technical Concept
Acceleration
400 kV
h=10
1.1–2.7
20
Ferrit ring core, "narrow" band cavities
Compression
640 kV
h=2
0.3950.485
16
Magnetic alloy ring core, broad band,
low duty cycle cavities
Barrier Bucket
15kV
2
2
Magnetic alloy ring core, broad band,
low duty cycle cavities
SIS18 bunch compressor
SIS100 installation
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS18: Versatile synchrotron for all ions
Used for p to U acceleration for low and high currents:
Length
216 m
Injection
Multi-turn
Energy
11  2000 MeV/u
Ramp
0.5 – 1.5 s
Rf
0.8 – 5 MHz, h=4
Tune h/v
4.4 / 3.2
Focusing
Triplett/Duplett
Tune spread Up to 0.4
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
SIS300 Lattice of U92+ (Design Ions)
SIS300 for high energetic ions, design in U92+ at 30 GeV/u and stretcher for slow extraction:
 curved cosθ magnets with Bmax= 4.5 T, 1 T/s ramping
 Lattice optimized for slow extraction
Energy [GeV/u]
tune
Max. dispersion -D [m]
h/v
Max. β–function [m]
Natural chomaticity ξ
Acceptance
h/v
h/v
h/v
U 92+
1030
13.3 / 9.8
4.8 / -2.3
20.4 / 19.9
-1.36 / -1.37
50 / 44
x: 65 mm
y: 65 mm
1/6 of SIS300: Length 181 m
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities
Variation of bunch length at SIS18
SIS18:
 Multi-turn from LINAC  debunched beam at injection with 11 MeV/u ⇔ β= 15 %
 Adiabatic bunch capture
 Rf-swing: 0.8 MHz to 5 MHz
Varying bunch frequency
and bunching factor
P. Forck et al., GSI, th
Charmonix, Dec 2007
requirements
concerning tune
L.
Groening, Sept.
GSI-Palaver,
Dec.15th,
10 ,2003
2003, A dedicated proton accelerator for p-physics at theFAIR
future
GSI facilities