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Front End Studies- International Design Study Muon Collider

Front End Studies- International Design Study Muon Collider. David Neuffer January 2009. Outline. Front End for the Neutrino Factory/MC Concepts developed during study 2A Concern on V rf ’ as function of B sol Need baseline design for IDS need baseline for engineering study

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Front End Studies- International Design Study Muon Collider

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  1. Front End Studies-International Design StudyMuon Collider David Neuffer January 2009

  2. Outline • Front End for the Neutrino Factory/MC • Concepts developed during study 2A • Concern on Vrf’ as function of Bsol • Need baseline design for IDS • need baseline for engineering study • ~lower fields; medium bunch length • Other variations

  3. Official IDS layout

  4. Optimization for IDS p p π→μ π→μ FE Target FE Target Solenoid Solenoid Drift Drift Buncher Buncher Rotator Rotator Cooler Cooler 10 m 10 m ~100 m ~50 m ~32m ~51m 36m 52m up to ~100m m up to ~100m m • ISS study based on nB = 18 (280 MeV/c to 154 MeV/c) • Buncher 0 to 12MV/m; Rotator 12.5MV/m, B=1.75T (201.25 MHz) • Long system, • Obtain shorter version has nB = 10 (280 MeV/c to 154 MeV/c) • slightly higher fields (2T, 15MV/m) • Shorter bunch train

  5. V’rf may be limited in B-fields baseline has ~2T, ~15MV/m Potential strategies: Use lower fields (V’, B) <10MV/m at 1.5T? Use non-B = constant lattices alternating solenoid Magnetically insulated cavities Shielded rf lattices Use gas-filled rf cavities but electron effects? Use Be Cavities should have better B/ V’rf Possible rf cavity limitations

  6. Shielded rf cooling channel (C. Rogers) • Lattice that keeps B small within rf cavities • Iron placed around coils • B < 0.25T at rf • Problems • rf occupancy ~1/3 • larger β* (~1m) • tranverse acceptance • Only in cooling section … • Still has fair cooling • increases μ/p by 1.7 3m rf cavity rf cavity

  7. Front End ReOptimization p π→μ FE Target Solenoid Drift Buncher Rotator Cooler 18.9 m ~60.7 m ~33m 42m up to ~100m m • Change reference B-field to 1.5T • constant B to end of rotator • changing to nB =“12” example • A bit longer than nB = 10 • optimize with lower fields • V’rf < 12 MV/m • Will see if we can get “better” optimum

  8. Parameters of candidate release • Initial drift from target to buncher is 79.6m • 18.9m (adiabatic ~20T to ~1.5T solenoid) • 60.7m (1.5T solenoid) • Buncher rf – 33m • 320  232 MHz • 0  9 MV/m (2/3 occupancy) • B=1.5T • Rotator rf -42m • 232  202 MHz • 12 MV/m (2/3 occupancy) • B=1.5T • Cooler (50 to 90m) • ASOL lattice, P0 = 232MeV/c, • Baseline has 15MV/m, 2 1.1 cm LiH absorbers /cell

  9. Some differences • Used ICOOL to set parameters • ACCEL model 10, • Phase Model 0 – • zero crossing set by tREFP 1 • refp 1 @ 233MeV/c, • 2 at 154MeV/c, 10 λ • Cool at 232 MeV/c • ~10% higher momentum • absorbers ~10% longer • Cools transverse emittance from 0.017 to 0.006m μ/8 GeV p 0.08 0.00

  10. Beam Through System z=80m z=0 z=156m z=111m ∆n=10 z=236m

  11. Varying Buncher/Rotator Voltage • Vary buncher/rotator gradients from baseline to explore sensitivity to gradient limits. • same baseline cooling channel (16MV/m, 1.15cm LiH) • 15 MV/m -> 1.1cm Li H • Somewhat less sensitive than previous cases

  12. More realistic models • For buncher & rotator replace B=1.5T with “realistic” solenoid coils • (B ~1.5T) • 0.5 m long, 0.25m spacing • ~OK for rf feed in between • ICOOL simulation shows no change in performance • (<~1%) • Next: rf • smaller number of rffrequencies • 14 ,B 16 R rf freq. OK • 7,8 20% less • Set rf power requirements

  13. rf requirements • Buncher – 13 rf frequencies • 319.63, 305.56, 293.93,285.46, 278.59, 272.05, 265.80, 259.83, 254.13, 248.67, 243.44, 238.42, 233.61 (13 f) • ~100MV total • Rotator – 15 rf frequencies • 230.19, 226.13, 222.59, 219.48, 216.76, 214.37,212.28, 210.46,208.64, 206.90, 205.49,204.25, 203.26, 202.63,202.33 (15 f) • 336MV total, 56 rf cavities • Cooler • 201.25MHz –up to 75m ~750MV • ~15 MV/m, 100 rf cavities

  14. Buncher rf cavity requirements RF frequency Total voltage cavities Gradient Rf Power 319.63 1.368 1 (0.4m) 4 MV/m 305.56 3.915 2 (0.4m) 5MV/m 293.93 3.336 2 (0.45m) 4 MV/m 285.46 4.803 2 (0.45m) 5.5MV/m 278.59 5.724 2 (0.45m) 6.4 MV/m 272.05 6.664 3 (0.45m) 5MV/m 265.80 7.565 3 (0.45m) 5.7MV/m 259.83 8.484 3 (0.45m) 6.5MV/m 254.13 9.405 3 (0.45m) 7MV/m 2.25 248.67 10.326 4 (0.45m) 6MV/m 243.44 11.225 4(0.45m) 6.5MV/m 238.42 12.16 4 (0.45m) 7MV/m 233.61 13.11 4 (0.45m) 7.5MV/m 3.5 98.085 0.2 0.6 0.5 1.0 1.25 1.5 1.5 2 2.25 2.5 3 MW

  15. Rf Rotator/ Cooler requirements • RF Rotator • 56 cavities (15 frequencies) • 12 MV/m, 0.5m • ~2.5MW (peak power) per cavity • Cooling System – 201.25 MHz • 100 0.5m cavities (75m cooler), 15MV/m • ~5MW /cavity

  16. Add Windows effects • ISS had windows … • 200μ Be – 7MV/m cavities • (0.12 MeV energy loss) • 395 μ Be – 10MV/m cavities • (0.24 MeV energy loss) • 750 μ Be – 12.5MV/m cavities (Rotator) • (0.45 MeV energy loss) • MICE rf cavities • 380 μ Be window design • For IDS ?? • Use 200 μ Be for Buncher • Use 400 μ Be for Rotator • Could use Be-grid or “open-cell” ?

  17. How Long a Bunch Train for IDS? • ISS study alotted space for 80 bunches (120m long train) • 80m or 54 bunches is probably plenty Study 2A ~80m -20 100 nB =12 ~60m 40 -30

  18. From Juan G.’s studies 8GeV 20T beam from H. Kirk Also 8GeV 30T beam New H. Kirk initial beam 20 T, 8 GeV beam, Hg target from more recent MARS (?)– (subtract 2.9ns to get mean of 0) more π/8GeV p (~10%) Tried 30T initial beam scaled 20 to 1.5T to 30 to 2.25 to 1.5T ~20 to 25% more than with 20T Recent Studies

  19. Plans etc. • Move toward “realistic” configuration • add Be windows • Set up design for cost algorithm • rf cavity design (pillbox, dielectric) • rf power requirements • Magnet design • Continuing front end IDS design study • C. Rogers, G. Prior, D. Neuffer, C. Yoshikawa, K. Yonehara, Y. Alexahin, M. Popovic, Y. Torun, S. Berg, J. Gallardo, D. Stratakis … • ~Biweekly phone Conference • Cost meeting at CERN March • April at Fermilab (IDS meeting)

  20. Quasi-Isochronous Muon Capture • Front end with isochronous HCC • 2009 SBIR w C. Yoshikawa

  21. U Miss reminds me of my university days

  22. Study2B June 2004 scenario (ISS) • Drift –110.7m • Bunch -51m • 12 rf freq., 110MV • 330 MHz  230MHz • -E Rotate – 54m –(416MV total) • 15 rf freq. 230 202 MHz • P1=280 , P2=154NV = 18.032 • Match and cool (80m) • 0.75 m cells, 0.02m LiH • Captures both μ+ and μ- • ~0.2μ/(24 GeV p)

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