L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

FAIR Requirements for Tune DeterminationP.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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

The FAIR Facility

UNILAC & SIS18 as injector for ions after upgradep-LINAC: high current 70 mA, 70 MeVSIS100: 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/sCR: stochastic cooling of RIB and pbarRESR: accumulation of pbar, deceleration of RIB, 1 T/sNESR: versatile experimental ring for stable, RIB, pbar e-cooling, gas-target, e-A colliderHESR: acc. of pbar to max. 14 GeV, pellet target, stochastic & e-coolingHEBT: for fast & slow extraction and low & high currents. Status: Funding of most parts recently achieved!

pbar

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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. Ions, slow extr. protons

Energy [GeV] U 28+ : 0.2 2 maximal 229

Tune h/v 18.84 / 18.73 17.30 / 17.42 20.84 / 20.73

Max. dispersion -D [m] 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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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 turnsResult: 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≈ 0.01DA for statically distributed dipole and quad errors:

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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

Experimentsat CERN andSIS18 ongoing

Addition problem: vacuum pressure increase by chemical desorption at vessel surface

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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%

Dipole

Collimator + strong pumping

Yellow: U28+

Red: U29+

Demonstration: ‘vacuum instability’ at SIS18

for 7 MeV/u U28+:

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Injection: 2 bunches at 4 batches, 200 MeV/u for U28+

1. 1 s storage β=0.5, long bunches to reduce tune spread2. Acceleration within 300 ms up to β=0.953. 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 Q00.01 due to tune spread and chromaticity about -1 (uncorrected)

SIS100 Filling and Acceleration: Design Ion U28+

Action time GeV/u bunches BfIon/bunch Δp/p ‰ ΔQ Remark

Accumulation 1 s 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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Collector Ring CR: bunch rotation adiabatic de-bunching stochastic cooling e.g. 10 s for pbar

Bunch Compression in SIS100 and Injection to Storage Rings

Target

Short pulses 25 to 60 ns for low emittance of RIB and pbar

SIS100: maximal ΔQ 1 during bunch rotation Acceleration

Barrier bucket

Moving barriers

Rotated bunch

Pre-compression

SIS100 circumference

50 ns

2.5 %

0.5 %

0.75 %

bunch rotation

adiabatic debunching

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Storage Ring Complex

from SIS18 SIS100, RIB at 740 MeV/u, pbar at 3 GeV

atomic physics HITRAP, FLAIR

NESRe--coolingdeceleration RIB experimentsAtomic physics

RESR1011 pbar accumulationstochastic coolingfast RIB/pbar decelerationStorage time up to 1 h

Electron ring

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

Collector Ring CRfixed rigiditybunch rotationstochastic coolingisochronous mode RIBStorage time < 10 s

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

RIBs and Antiprotons at CR and RESR

CR

RESR

CR RIB: fixed energy 740 MeV/u Lifetime measurement, stochastic cooling 1.5 sCR pbar: fixed energy 3 GeV/u Stochastic cooling within 10 sRESR RIB: decelerationRESR: pbar: accumulation with stochastic coolingTune measurement: partly dc-beam Schottky Tune feedback: NOT required during cooling But for 1 s deceleration to prevent for losses

CR

RIB

CR pbar

RESR RIB

RESR pbar

Length 215 m 248 m

Energy MeV/u 740 3000 740100 3000100

Qx / Q y4.42/4.24 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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

NESR: Versatile Storage Ring for Physics Experiments

Length 222 m

EnergyMeV/u

RIB: 740 4 Pbar: 3000 30

Tune h/v 3.19/1.86

Momentum accept. 1.5 %

Trans. Accept. 160/4010-6 m

Ions operation with RIB and stable ions: Storage and cooling for 740 4 MeV/u Deceleration 1 T/s maximal Experiments with internal targetsSlow and fast extraction after decelerationpbar: Deceleration 1 T/s max down to 30 MeV Electron cooling at top and intermediate energyDeceleration: Tune feedback to prevent for lossesAt storage: dc-beams Schottky better suited No tune feedback during cooling, otherwise two active systems

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Antiproton Storage Ring HESR

Length 574 m

Injection energy 3 GeV

Final energy 0.8 – 14 GeV

Rigidity 50 Tm, n-c

Ramp rate 0.1 T/s

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 coolingTune feedback: during (slow) acceleration

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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 rangeTune feedback during deceleration (to low rigidity) to prevent for particle loss (n.c. magnets)

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Slow extraction:Different working points Qx = 17.42 17.32Qy = 17.35 17.3 to fulfill Hard-condition

SIS100 dynamic aperture calculation: Slow extraction

At injection 200 MeV/u U28+:

At extraction 1.5 GeV/u U28+:

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

Proton working point Qx = 21.85 and Qy=21.79

SIS100 dynamic aperture calculation: Proton injection

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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

0.395-

0.485

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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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

U 92+

Energy [GeV/u] 1030

tune h/v 13.3 / 9.8

Max. dispersion -D [m] 4.8 / -2.3

Max. β–function [m] h/v 20.4 / 19.9

Natural chomaticity ξ h/v -1.36 / -1.37

Acceptance h/v 50 / 44

x: 65 mm

y: 65 mm

1/6 of SIS300: Length 181 m

L. Groening, Sept. 15th, 2003GSI-Palaver, Dec. 10th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities

P. Forck et al., GSI, Charmonix, Dec 2007 FAIR requirements concerning tune

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 MHzVarying bunch frequency and bunching factor