1. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 I. Strasik 1, I. Prokhorov 1,2 and O. Boine-Frankenheim 1,2 1 GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany 2 Technical University Darmstadt, Germany

2. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Introduction  FAIR – Facility for Antiproton and Ion Research at GSI  Synchrotron SIS 100 (fixed target) 1 Beams - protons (antiproton production) - fully-stripped ions (e.g. ) - partially-stripped ions (e.g. ) Lattice - circumference ~ 1 km - hexagonal shape (six superperiods) - quadrupole doublet structure - superconducting magnets one superperiod

3. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 SIS 100 synchrotron AcceleratorBeamEnergy Intensity / Cycle SIS 18 protons4.5 GeV6×10 11 238 U 28+ 200 MeV/u5×10 9 SIS 100 protons30 GeV2×10 13 238 U 28+ 2.7 GeV/u4×10 11 Beam Number of bunches Intensity Maximum beam energy [GeV] Total beam energy [MJ] SIS 100 proton1, 2, 4 2.0  10 13 290.093 SIS 100 238 U 28+ 1, 2, 4 4.0  10 11 643 (2.7 GeV/u)0.051 LHC proton2808 1.15  10 11 7000362  Total beam energy  Beam parameters 2

4. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Need for the halo collimation in SIS 100  Heavy ions  Protons and light ions Activation ("hands-on" maintenance limit) 1 W/m (1 GeV protons), 5 W/m (1 GeV/u uranium ions) Quenches Vacuum degradation due to desorption process Radiation damage [Ref] I. Strasik et al., Physical Review ST AB 13, (2010) [Ref] E. Mahner, Physical Review ST AB 11, (2008) Uranium beam experiments, GSI 3

5. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Interaction with residual gas: U 28+ → U 29+. Cryocatchers - a combined collimation/pumping system developed to intercept heavy ions which lost electrons due to interaction with residual gas. Minimize the desorbed gas entering the beam pipe. Important also for the halo collimation [Ref] L. Bozyk et al., Proceedings of the IPAC’12, p. 3237. Cryocatchers in SIS 100 cryocatchers prototype Courtesy Lars Bozyk 4

6. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 [Ref] L. Bozyk et al., Proceedings of the IPAC’12, p. 3237. Cryocatchers in SIS 100 Courtesy Lars Bozyk Particle tracking: Stripped ions distribution: 5

7. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Two-stage betatron collimation system Primary collimator (thin foil) – scattering of the halo particles Secondary collimators (bulky blocks) – absorption of the scattered particles Particles have small impact parameter on the primary collimator. The impact parameter at the secondary collimator is enlarged due to scattering → reduced leakage of the particles. [Ref] M. Seidel, DESY Report, 94-103, (1994). [Ref] T. Trenkler and J.B. Jeanneret, Particle Accelerators 50, 287 (1995). [Ref] J.B. Jeanneret, Phys. Rev. ST Accel. Beams 1, 081001 (1998). [Ref] K. Yamamoto, Phys. Rev. ST Accel. Beams 11, 123501 (2008). [Ref] N. Mokhov et al., Journal of Instrum. 6, T08005 (2011). 6

8. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Collimation of protons and fully-stripped ions Location of the collimation system in SIS 100 SIS 100, Sector 1 - straight section, cell 3 and 4 rectangular aperture Parameters of the collimators CollimatorPrimarySecondary Materialtungsten Thickness1 mm40 cm Transverse position4.5 σ5 σ 7

9. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Lattice and beam parameters Operation modeQxQx QyQy Proton21.817.7 Ion (slow extraction)17.3117.8 Ion (fast extraction)18.8818.8 Beam  x [mm·mrad]  y [mm·mrad] Proton134 238 U3414 Ion operation (fast extraction) 8

10. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Efficiency of the proton beam collimation Simulation tools Beam-material interaction: FLUKA Statistics: 700 000 particles Particle tracking: MAD-X Efficiency: ~ 99 % 9

11. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Importance of the impact parameter 10 1 mm IP = 10  m IP = 1  m IP = 0.5  m IP = 0.1  m IP = 0.01  m

12. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Impact parameter and beam energy Dependence of the collimation efficiency on the impact parameter and beam energy. 11

13. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Collimation of fully-stripped ions Two-stage collimation system utilize also for fully-stripped ions Study of the following processes for various ion species Reference quantity - magnetic rigidity Injection and extraction energy Scattering in the primary collimator Molière theory (multiple Coulomb scattering), ATIMA code, FLUKA code Energy (momentum) losses in the primary collimator Bethe formula, ATIMA code, FLUKA code Inelastic nuclear interactions in the primary collimator Sihver, Tripathi, Kox, Shen formulae, FLUKA code Collimation efficiency Dependence on the ion species 12

14. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Magnetic rigidity Reference quantity → magnetic rigidity Magnetic rigidity → injection and extraction energy of the beam 13

15. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Scattering in the primary collimator Molière theory of multiple Coulomb scattering [Ref] J. Beringer et al. (Particle Data Group), Phys. Rev. D86, 010001 (2012). ATIMA code (1 mm, tungsten) ATIMA vs FLUKA 14

16. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Momentum losses in the primary collimator Bethe formula [Ref] J. Beringer et al. (Particle Data Group), Phys. Rev. D86, 010001 (2012). ATIMA code (1 mm, tungsten) ATIMA vs FLUKA 15

17. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Inelastic nuclear interactions - Sihver formula (E > 100 MeV/u) [Ref] L. Sihver et al., Phys. Rev. C47, 1225 (1993). - Tripathi formula (E > 10 MeV/u) [Ref] R. Tripathi et al., NIMB117, 347 (1996). Cross section for inelastic nuclear interaction - Kox formula (E > 10 MeV/u) [Ref] Kox et al. Phys. Rev. C35, 1678 (1987). - Shen formula (E > 10 MeV/u) [Ref] Shen et al. Nucl. Phys. A491, 130 (1989). Tripathi (1 mm, tungsten) Probability P Beam 1 H 1+40 Ar 18+238 U 92+ Tripathi0.0110.0310.057 FLUKA0.0110.0320.114 Tripathi vs FLUKA (B  = 18Tm) Discrepancy for heavy ions - EMD 16

18. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Choice of the material for the primary collimator High-Z materials are preferable. 17 40 Ar ions

19. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Efficiency of the ion beams collimation Simulation tools Beam-material interaction: ATIMA, FLUKA Statistics: 100 000 particles Particle tracking: MAD-X 18

20. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Impact parameter and imperfections of the lattice Dependence of the collimation efficiency on the impact parameter and COD. 19 1 mm ± 30 %magnet misalignment

21. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Collimation of partially-stripped ions Intermediate charge-state ions will be accelerated in SIS 100. [Ref] FAIR - Baseline Technical Report, GSI Darmstadt, (2006). Colimation concept - Stripping foil: - Deflection by a beam optical element 20

22. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Collimation of partially-stripped ions Slow extraction area in SIS 100 [Ref] A. Smolyakov at al, EPAC2008, 3602 (2008). Slow extraction area - two warm quadrupoles The stripping foil for the halo collimation is placed in the slow extraction area in SIS 100 SIS 100 / Sector 5 / Cell 2 stripping foil Cell 3 warm quadrupoles beam direction 21

23. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Charge state distribution after stripping injection energies high energies (2 GeV/u) fully-ionized state equilibrium charge-state distribution [Ref] C. Scheidenberger et al., NIMB 142 (1998) 441. code GLOBAL Stripping foil: 500 μm thick, titanium Medium-Z materials (Al – Cu) → optimal for efficient stripping for wide range of projectiles and beam energies Electron capture and electron loss 22

24. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Particle tracking of stripped ions Horizontal Vertical 23

25. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Charge state distribution after stripping Horizontal Vertical 24

26. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Conclusion Efficiency of the proton beam collimation: ~ 99%. Efficiency of the ion beam collimation: ~ 99% for fully-stripped ions < 20 Ne. Efficiency of the ion beam collimation + cryocatchers: ~ 99% for fully-stripped ions < 132 Xe. Efficiency of the ion beam collimation + cryocatchers: almost 90% for 238 U. The collimation concept for the partially-stripped ions is based on the stripping of their electrons The stripped ions are then deflected using two warm quadrupoles. 25

27. I. Strasik et al. ● Halo Collimation of Proton and Ion Beams in FAIR Synchrotron SIS 100 ● CERN 27.01.2014 Thank you for your attention