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

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Presentation on theme: "L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities P. Forck et al.,"— Presentation transcript:

1 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 Determination P.Forck 1,G.Franchetti 1,V.Kornilov 1,P.Kowina 1,J.Dietrich 2 for the FAIR Team 1 GSI, Darmstadt and 2 FZJ, Jülich  Brief overview of F aclity for A ntiproton and I on R esearch  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

2 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 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*10 13, U 28+ 5*10 11 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

3 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 U 28+ operation (Design Ions) Different tunes are required for ions fast / slow extraction and p operation:  Large acceptance, low dispersion for bunch compression, high γ t, 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 maximal2  29 Tuneh/v18.84 / / / Max. dispersion -D [m] Max. β–function [m]h/v19.6 / / / 19.9 Natural chomaticity ξh/v-1.19 / / / Design injected emittance εh/vU 28+ : 35 / 15 Design injected Δp/ph/vU 28+ : 0.5 ‰0.2 ‰ x: 80 mm y: 40 mm 1/6 of SIS100: Length 181 m

4 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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: U 28+ at 200 MeV/u injection energy 4 injected batches, 2 bunches each, 1 s max. storage = 1.1∙10 6 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 Q 0 ≈ 0.01 DA for statically distributed dipole and quad errors: 

5 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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  Experiments at CERN and SIS18 ongoing Addition problem: vacuum pressure increase by chemical desorption at vessel surface

6 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 U 28+  U 29+ 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: U 28+ Red: U 29+ Demonstration: ‘vacuum instability’ at SIS18 for 7 MeV/u U 28+ :

7 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 U s storage β=0.5, long bunches to reduce tune spread 2.Acceleration within 300 ms up to β= 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 Q 0  0.01 due to tune spread and chromaticity about -1 (uncorrected) SIS100 Filling and Acceleration: Design Ion U 28+ ActiontimeGeV/ubunchesBfBf Ion/bunchΔp/p ‰ΔQΔQRemark Accumulation1 s0.28, h=100.45∙ Sine wave Acceleration0.5 s1.58, h=100.35∙ Sine wave Pre-compression0.1 s ∙ Barrier bucket At compression0.1ms1.51, h=20.055∙ Rotated to 60 ns

8 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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

9 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 NESR e - -cooling deceleration RIB experiments Atomic physics RESR pbar accumulation stochastic cooling fast RIB/pbar deceleration Storage 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 CR fixed rigidity bunch rotation stochastic cooling isochronous mode RIB Storage time < 10 s

10 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 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 CR pbar RESR RIB RESR pbar Length215 m248 m Energy MeV/u   100 Q x / Q y 4.42/ / /3.31 Trans.Acept Long. Acept.1.7%3.0%0.1% RESR

11 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 Length222 m Energy MeV/u RIB: 740  4 Pbar: 3000  30 Tune h/v3.19/1.86 Momentum accept.  1.5 % Trans. Accept. 160/40  10-6 m Ions operation with RIB and stable ions:  Storage and cooling for 740  4 MeV/u  Deceleration 1 T/s maximal  Experiments with internal 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

12 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 Length574 m Injection energy3 GeV Final energy0.8 – 14 GeV Rigidity50 Tm, n-c Ramp rate0.1 T/s pbar collisions with proton for hadron spectroscopy Acceleration from 3 to 14 GeV or deceleration to 1 GeV # of pbar: for Δp/p=4∙10 -5 for high resolution 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

13 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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. U 28+ : β=0.5 → 0.95 ⇔ 10 th 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 ΔQ 0 ≈ 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)

14 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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

15 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 Q x =  Q y =  17.3 to fulfill Hard-condition SIS100 dynamic aperture calculation: Slow extraction At injection 200 MeV/u U 28 + : At extraction 1.5 GeV/u U 28 + :

16 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 = and Qy=21.79 SIS100 dynamic aperture calculation: Proton injection

17 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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-SystemTotal Pf [MHz]#Technical Concept Acceleration400 kV h=10 1.1–2.720Ferrit ring core, "narrow" band cavities Compression640 kV h= Magnetic alloy ring core, broad band, low duty cycle cavities Barrier Bucket15kV22Magnetic alloy ring core, broad band, low duty cycle cavities SIS18 bunch compressor SIS100 installation

18 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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: Length216 m InjectionMulti-turn Energy 11  2000 MeV/u Ramp0.5 – 1.5 s Rf0.8 – 5 MHz, h=4 Tune h/v4.4 / 3.2 FocusingTriplett/Duplett Tune spreadUp to 0.4

19 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 U 92+ (Design Ions) SIS300 for high energetic ions, design in U 92+ at 30 GeV/u and stretcher for slow extraction:  curved cosθ magnets with B max = 4.5 T, 1 T/s ramping  Lattice optimized for slow extraction U 92+ Energy [GeV/u] 10  30 tuneh/v13.3 / 9.8 Max. dispersion -D [m]4.8 / -2.3 Max. β–function [m]h/v20.4 / 19.9 Natural chomaticity ξh/v-1.36 / Acceptanceh/v50 / 44 x: 65 mm y: 65 mm 1/6 of SIS300: Length 181 m

20 L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 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 MHz  Varying bunch frequency and bunching factor


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