MEIC Ion Linac and Pre-Booster Design

1. MEIC Ion Linac and Pre-Booster Design Bela Erdelyi Department of Physics, Northern Illinois University, and Physics Division, Argonne National Laboratory

2. Joint Work of Bela Erdelyi (NIU/ANL) Shashikant Manikonda (ANL) Peter Ostroumov (ANL) Sumana Abeyratne (NIU student) With assistance from JLab staff (Y. Derbenev, Y. Zhang, G. Krafft, etc.) Acknowledgements

3. ELIC Conceptual Layout • Three compact rings: • 3 to 11 GeV electron • Up to 12 GeV/c proton (warm) • Up to 60 GeV/c proton (cold)

4. Pulsed linac Short Normal Conducting section: RFQ and IH structure Followed by Superconducting section that contains Stripper for heavy ions at 12 MeV/u Ion Linac for ELIC

5. Linac layout Basic Parameters of the Linac Normal conducting Superconducting 80

6. Developed for the RIA/FRIB project QWR HWR DSR Superconducting Cavities

7. Voltage Gain per Cavity forProtons and Lead Ions

8. QWR, f=109 MHz, =0.15 HWR, f=172 MHz, =0.26 QWR and HWR production at ANL

9. beam Cryomodule assembly at ANL

10. Purpose: Inject from linac Accumulate ions Accelerate them Extract and send to large booster Concepts: Figure-8 shape for ease of spin transport, manipulation and preservation Modular design, with (quasi)independent module design optimization FODO arcs for simplicity and ease of implementation of optics correction schemes No dispersion suppressors Injection insertion Doublet/Triplet straights for long dispersion-less drifts Matching/tuning modules in between Accumulator/Pre-Booster Concept

11. Figure-8 shaped; circumference ~250 m Maximum bending field: 1.5 T Maximum quadrupole gradient: 20 T/m Momentum compaction smaller than 1/25 Maximum beta functions less than 35 m Maximum full beam size less than 2.5 cm and 1 cm vertically in dipoles 5m m long dispersion-less sections for RF cavities, electron cooling collimation and extraction Sizable (normalized) dispersion for/at injection Working point chosen such that tune footprint does not cross low order resonances (tunability) Constraints

12. Protons (and light ions) Stripping injection Heavy ions Repeated multi-turn injection Transverse (horizontal and possibly also vertical) and longitudinal painting Electron cooling for stacking/accumulation Injection

13. Heavy-Ion Injection

14. h=1 RF swing necessary is [0.4,2] MHz 15 kV per cavity 50kV/turn => 3-4 cavities 56000 turns for 200MeV -> 3 GeV Less than 80 ms acceleration time Acceleration

15. Conventional fast extraction Extraction

16. Layout ARC 1 Collimation Electron Cooling Extraction Non dispersive section 1 Injection Insertion section ARC 3 Non dispersive section 2 ARC 2 RF cavity Beam from LINAC Solenoid for Electron Cooling

17. Linear Optics Arc 2 Arc 1 Injection Arc 3 Straight 2 Straight 1

18. Optical modules ARC1&2 FODO ARC3 FODO INJECTION INSERT STRAIGHT TRIPLET

19. Tunability

20. Main Parameters

21. Magnets

22. Presented a preliminary design of the linac and the accumulator/pre-booster, which satisfy the constraints while providing superior performance Fine tuning first order optics Space charge limits on current and emittance Spin and spin-orbit resonance analysis Dynamic aperture estimation Summary and Work in Progress

23. BACKUP SLIDES

24. 4 kW capacitive coupler Adjustable 1 cold/warm windows Pneumatic slow tuner Cavity subsystems • Piezoelectric tuner (PZT) • ~90 Hz window • 35 m displacement beam PZT has been tested with excellent performance

25. Proton beam Setting 1: Mass= 1, Charge= 1, Kinetic Energy = 3000 MeV Electric rigidity (χe) = 3.71E+9 V Magnetic Rigidity (χm) = 12.74 Tm Proton beam Emittance in x and y = 16 π mm·mrad x=± 4mm y=± 4mm , a=±4mrad b = ±4mrad Kinetic Energy Dispersion (δKE/KE )= 1E-4 Setting 2: Mass= 1, Charge= 1, Kinetic Energy = 200 MeV Electric rigidity (χe) = 3.68E+8 V Magnetic Rigidity (χm) = 2.14 Tm Proton beam Emittance in x and y = 140π mm·mrad x=± 4mm y=± 4mm , a=±35mrad b = ±35mrad Kinetic Energy Dispersion (δKE/KE )= 1E-2 25 29-31 July,2010

26. Energy range Protons: from 200 MeV (β=0.57, γ=1.21) @ injection to 3 GeV (β=0.97, γ=4.2) at extraction Lead ions: if fully stripped, from 80 MeV/u (β=0.39, γ=1.08) @ injection to 1.18 GeV/u (β=0.9, γ=2.26) @ extraction Circumference An integer multiple of it must be ~900-1000 m => ~250-300 m Main Parameters (1)

27. Revolution times/frequencies Protons @ injection: {0.883753 μs,1.13154 MHz} if C=150m {0.515181 μs,1.94107 MHz} if C=300m Protons @ extraction: {1.76751 μs,0.565769 MHz} if C=150m {1.03036 μs,0.970533 MHz} if C=300m Pb @ injection: {1.29609 μs,0.771552 MHz} if C=150m {0.557907 μs,1.79241 MHz} if C=300m Pb @ extraction: {2.59218 μs,0.385776 MHz} if C=150m {1.11581 μs,0.896207 MHz} if C=300m If acceleration done with h=1 RF swing necessary is [0.38,1.95] MHz Main parameters (2)

28. Assuming: 3 m long cooling section 300 mA electron current 2.5 cm beam radius ± 5 mrad beam divergence ±0.004 momentum dispersion Cooling for 3 time constants Transverse cooling time: ~ 130 ms Longitudinal cooling time: ~ 67 ms Cooling electron energies: @ injection: { 0.55394 MeV, γ=2.0840 } @ extraction: { 1.15511 MeV, γ=3.2605 } Cooling times

29. @ injection Q (0) Q (1) Q (2) Q (3) Q (4) 0 4% 70% 22% 3% @ extraction Q (0) Q (1) 83% 17% Lead Charge Distributions

30. Protons If assuming 1A current, depending on circumference and injection/extraction: => N_p ~ [ 3 , 11 ] x 1012 Lead ions Under similar circumstances: => N_Pb ~ N_p / Q Intensities

31. Assuming 5x1010 lead ions need to be accumulated One linac pulse delivers ~2x108 ions (assumed @ ~50% efficiency) 50 linac pulses, 250 μs each Total time = 50x 250 μs +50x130 ms+2x80 ms ≈ 7 s Pre-Booster Cycle Time

32. Shorter Version Layout 29-31 July,2010

33. Shorter Version Lattice functions 29-31 July,2010

34. Shorter Version Parameters 29-31 July,2010

35. Shorter Version Magnets

36. New Layout with 5 quads in each matching section (302m)