Page 1 Review 09/2010 MEIC Ion Linac and Pre-Booster Design Bela Erdelyi Department of Physics, Northern Illinois University, and Physics Division, Argonne National Laboratory

Page 2 Review 09/2010 Acknowledgements 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.) 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.)

Page 3 Review 09/2010 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)

Page 4 Review 09/2010 Ion Linac for ELIC Pulsed linac Short Normal Conducting section: RFQ and IH structure Followed by Superconducting section that contains Stripper for heavy ions at 12 MeV/u

Page 5 Review 09/2010 Basic Parameters of the Linac Linac layout Normal conductingSuperconducting 80

Page 6 Review 09/2010 Superconducting Cavities Developed for the RIA/FRIB project QWR HWR DSR

Page 7 Review 09/2010 Voltage Gain per Cavity for Protons and Lead Ions

Page 8 Review 09/2010 QWR and HWR production at ANL QWR, f=109 MHz,  =0.15 HWR, f=172 MHz,  =0.26

Page 9 Review 09/2010 Cryomodule assembly at ANL beam

Page 10 Review 09/2010 Accumulator/Pre-Booster Concept 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

Page 11 Review 09/2010 Constraints 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)

Page 12 Review 09/2010 Injection 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

Page 13 Review 09/2010 Heavy-Ion Injection

Page 14 Review 09/2010 Acceleration h=1 RF swing necessary is [0.4,2] MHz 15 kV per cavity 50kV/turn => 3-4 cavities turns for 200MeV -> 3 GeV Less than 80 ms acceleration time

Page 15 Review 09/2010 Extraction Conventional fast extraction

Page 16 Review 09/2010 Layout ARC 1 Injection Insertion section ARC 2 Non dispersive section 1 ARC 3 Non dispersive section 2 RF cavity Electron Cooling Solenoid for Electron Cooling Extraction Collimation Beam from LINAC

Page 17 Review 09/2010 Linear Optics Injection Arc 1 Straight 1 Arc 3 Straight 2 Arc 2

Page 18 Review 09/2010 Optical modules ARC1&2 FODOARC3 FODO STRAIGHT TRIPLET INJECTION INSERT

Page 19 Review 09/2010 Tunability

Page 20 Review 09/2010 Main Parameters UnitsValue 1Circumferencem302 2Angle at crossingdeg44 3Number of dispersive FODO cells (Type I)6 4Number of dispersive FODO cells (Type II)8 5Number of triplet cells18 6Number of matching cells (2 types)4 7Minimum drift length between magnetscm50 8Drift length in the injection insertionm5.0 9Drift lengths between triplets (for RF, extraction, collimation and electron cooling)m5.3 10Beta maximum in Xm33 11Beta maximum in Ym36 12Maximum beam sizecm2.3 12Maximum vertical beam size in the dipole magnetscm0.6 13Maximum dispersion (x|delta_KE)m3.3 14Normalized dispersion value at injection insertm½m½ Tune in X Tune in Y Gamma of particle Gamma at transition energy5.6 19Momentum compaction3.2E-2

Page 21 Review 09/2010 Magnets Quantity ParametersUnitsValue 1Quadrupole Magnets113 Lengthcm40 Half aperturecm5 Maximum pole tip fieldT1.5 Minimum pole tip fieldT0.15 2Dipole Magnets (Type I)16 StrengthT1.41 Radiusm9.0 Vertical aperturecm3.0 Angledeg11.6 Lengthm1.83 3Dipole Magnets (Type II)18 StrengthT1.41 Radiusm9.0 Vertical aperturecm3.0 Angledeg14.0 Lengthm2.19

Page 22 Review 09/2010 Summary and Work in Progress 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 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

Page 23 Review 09/2010 BACKUP SLIDES

Page 24 Review 09/2010 Cavity subsystems 4 kW capacitive coupler Adjustable 1 cold/warm windows Pneumatic slow tuner Piezoelectric tuner (PZT) ~90 Hz window 35  m displacement beam PZT has been tested with excellent performance

Page 25 Review 09/2010 Proton beam Setting 1: Mass= 1, Charge= 1, Kinetic Energy = 3000 MeV Electric rigidity (χ e ) = 3.71E+9 V Magnetic Rigidity (χ m ) = 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 (χ e ) = 3.68E+8 V Magnetic Rigidity (χ m ) = 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 July,2010

Page 26 Review 09/2010 Main Parameters (1) Energy range Protons: from 200 MeV (β=0.57, injection to 3 GeV (β=0.97, γ=4.2) at extraction Lead ions: if fully stripped, from 80 MeV/u (β=0.39, injection to 1.18 GeV/u (β=0.9, extraction Circumference An integer multiple of it must be ~ m => ~ m

Page 27 Review 09/2010 Main parameters (2) Revolution times/frequencies injection: { μs, MHz} if C=150m { μs, MHz} if C=300m extraction: { μs, MHz} if C=150m { μs, MHz} if C=300m injection: { μs, MHz} if C=150m { μs, MHz} if C=300m extraction: { μs, MHz} if C=150m { μs, MHz} if C=300m If acceleration done with h=1 RF swing necessary is [0.38,1.95] MHz

Page 28 Review 09/2010 Cooling times 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 injection: { MeV, γ= extraction: { MeV, γ= }

Page 29 Review 09/2010 Lead Charge injection Q (0) Q (1) Q (2) Q (3) Q (4) 0 4% 70% 22% extraction Q (0) Q (1) 83% 17%

Page 30 Review 09/2010 Intensities Protons If assuming 1A current, depending on circumference and injection/extraction: => N_p ~ [ 3, 11 ] x Lead ions Under similar circumstances: => N_Pb ~ N_p / Q

Page 31 Review 09/2010 Pre-Booster Cycle Time Assuming 5x10 10 lead ions need to be accumulated One linac pulse delivers ~2x10 8 ions ~50% efficiency) 50 linac pulses, 250 μs each Total time = 50x 250 μs +50x130 ms+2x80 ms ≈ 7 s

Page 32 Review 09/ July,2010 Shorter Version Layout

Page 33 Review 09/ July,2010 Shorter Version Lattice functions

Page 34 Review 09/ July,2010 UnitsValue 1Total lengthm254 2Angle at crossingdeg60 3Number of dispersive FODO cells (Type I)6 4Number of dispersive FODO cells (Type II)8 5Number of triplet cells12 6Number of matching cells4 7Minimum drift length between magnetscm50 8Drift lengths in the insertion regionm5.0 9Drift lengths between triplets (for RF, collimation and electron cooling)m5.0 10Beta maximum in Xm32 11Beta maximum in Ym32 12Maximum beam sizecm2.5 12Maximum beam size in the dipole magnetscm0.6 13Maximum Dispersion (x|delta_KE)2.5 14Normalized dispersion value at injection (x|δ_KE)/√β Tune in X Tune in Y Gamma of particle Gamma at Transition Energy4.7 19Momentum compaction factor4.4E-2 Shorter Version Parameters

Page 35 Review 09/2010 Quantity ParametersUnitsValue 1Quadrupole Magnet95 Lengthcm40 Half aperturecm5 Maximum pole tip field T1.5 Minimum pole tip field T0.16 2Dipole Magnet (Type I)12 StrengthT1.41 Radiusm9 Vertical aperturecm3 Angledeg14 Lengthm2.19 3Dipole Magnet (Type II)18 StrengthT1.41 Radiusm9 Vertical aperturecm3 Angledeg12.9 Lengthm2.04 4Dipole Magnet (Type III)18 StrengthT1.41 Radiusm9 Vertical aperturecm3 Angledeg14.9 Lengthm2.35 Shorter Version Magnets

Page 36 Review 09/2010 New Layout with 5 quads in each matching section (302m)