Muon Accelerator R&D

1. Muon Accelerator R&D DOE Program Review May 17, 2006 A. Bross

2. Muon Accelerator R&D • Our activities focus on studying the accelerator physics of a Neutrino Factory and Muon Collider and developing the accelerator technologies that are required to make these facilities a reality • This work is being conducted within the Framework of the US Neutrino Factory and Muon Collider Collaboration (NFMCC) and consists of • Design and Simulation • Includes participation in international studies such as the International Scoping Study for a Future Neutrino Factory and Super-Beam Facility (ISS) • MuCool • MICE @ RAL • Targetry – MERIT @ CERN • Approximately 7 FTE physicist effort

3. Design and Simulation C. Johnstone, D. Neuffer, K. Paul, S. Poklonskiy K. Yonehara

4. Overview The International Scoping study of a Future Neutrino Factory and super-beam facility Muon Collider Neutrino Factory FS2A Concept

5. Cool here Design and Simulation -Some Specific Areas of Study m Capture/Bunch/Rotation/Cool Linear nonscaling FFAG Energy Time Two fixed point acceleration: half synchrotron oscillation + path between fixed points H2 filled cavities

6. m Capture/Bunch/Rot/Cool • Change pressure to 150Atm • Rf voltage to 24 MV/m • Transverse rms emittance cools 0.019 to ~0.008m • Acceptance ~0.22/p at εT < 0.03m • ~0.12/p at εT < 0.015m • About equal to Study 2B Transverse emittance Acceptance (per 24GeV p)

7. Cooling simulation results 0.5GeV 0 0.4m -0.4m 0.4m -50m 50m

8. Extraction reference orbit Injection reference orbit Injection reference orbit FFAG Studies Electron Model (EMMA) Host: Daresbury Laboratory U.K. downstream of their 8-35 MeV Energy Recovery Linac Prototype (ERLP) of the 4th Generation Light Source (4GLS Proton Model (PAMILA) Provisional Patent: Fermilab Host: Oxford University, U.K. • Tune-stabilized Nonscaling FFAG with no nonlinear fields • Strong + weak focusing machine • Applications • Carbon therapy • Proton driver Unprecedented momentum compaction Asynchronous gutter acceleration Resonance Crossing Evolution of phase space Validate concept for muon acceleration

9. MuCool A. Bross, S. Geer, A. Moretti, B. Norris, Z. Qian

10. MuCool Program • Currently consists of 9 institutions from the US and Japan • Mission • Design, prototype and test all cooling channel components (SFOFO) • 201 MHz RF Cavities, absorbers, SC solenoids • Support MICE (cooling demonstration experiment) • Perform high beam-power engineering test of cooling section components RF Development ANL Fermilab IIT JLAB LBNL Mississippi Absorber R&D Fermilab IIT KEK NIU Mississippi Osaka Solenoids LBNL Mississippi

11. R&D Focus of MuCool • Component testing Fermilab • RF Cavities • High RF-power Testing • Absorbers • Technology tests • High power-load testing • With beam • Magnets

12. MuCool Test Area • Facility to test all components of cooling channel (not a test of ionization cooling) • At high beam power • Designed to accommodate full Linac Beam • 1.6 X 1013p/pulse @15 Hz • 2.4 X 1014 p/s • » 600 W into 35 cm LH2 absorber @ 400 MeV • RF power from Linac (201 and 805 MHz test stands) • Waveguides pipe power to MTA

13. MTA Hall

14. MTA • The MTA is the focus of our Activities • RF testing (805 and 201 MHz) • High pressure H2 gas-filled RF • LH2 Absorber tests • Two parts of infrastructure yet to be completed • Cryo Plant • Beam Line

15. Phase I of RF Cavity Closed Cell Magnetic Field Studies (805 MHz) • Data seem to follow universal curve • Max stable gradient degrades quickly with B field • Sparking limits max gradient • Copper surfaces the problem Gradient in MV/m Peak Magnetic Field in T at the Window

16. Phase II of 805 MHz studies • Study breakdown and dark current characteristics as function of gradient and applied B field in Pillbox cavity • Curved Be window Test • TiN coated • Cavity has been conditioned to 32MV/m without B field • Measurements at 2.5T • So Far – stable gradient limited to about 14MV/m • Button test • Evaluate various materials and coatings • Quick Change over

17. RF R&D – 201 MHz Cavity Design • The 201 MHz Cavity is now operating • Recently reached 16MV/m at B=0 (design gradient!)

18. High Pressure H2 Filled Cavity WorkMuon’s Inc • High Pressure Test Cell • Study breakdown properties of materials in H2 • Just finished run in B field • No degradation in M.S.G. up to » 3.5T

19. Absorber Design Issues • 2D Transverse Cooling and • Figure of merit: M=LRdEm/ds M2 (4D cooling) for different absorbers H2 is clearly Best - Neglecting Engineering Issues Windows, Safety

20. Convective Absorber Activities • First Round of studies of the KEK absorber performed in the MTA • GHe used to input power

21. Convective Absorber Activities II

22. Convective Absorber Activities III • Next Round of tests will use a modified absorber • Test • Electrical Heater • New Temperature sensors • LH liquid level sensor Instrumentation will be used in MICE Absorber Body being modified in Lab 6 at Fermilab

23. LiH Test Program • Produce encapsulating cast (not pressed) samples • Small disk (5-10 cm) for intense radiation exposure • Look at Material stability primarily • Temperature Profile • Large disk (30 cm) for detailed thermal conductivity studies • External Cooling + Internal Heating • Potential absorber for MICE Phase I • Non-instrumented, no cooling

24. MICE A. Bross, M. Ellis, S. Geer, A. Moretti, D. Neuffer, M. Popovic, R. Rucinski

25. Focus Coils Muon Ionization Cooling Experiment MICE Coupling Coils Tracking Spectrometers Beam Diffuser Matching Coils Magneticshield RFCavities Liquid Hydrogen Absorbers Radiation shield

26. MICE – Precision Emittance Measurement • Expect 10% cooling (input 6π mm rad beam). • Wish to measure this change to ~ 1%. • Require measurement of emittance of beams into and out of cooling channel to 0.1%! • Cannot be done with conventional beam monitoring devices. • Instead, perform a single particle experiment: • High precision measurement of each track (position, momentum, time, energy). • Build up a virtual bunch offline. • Analyse effect of cooling channel on many different bunches. • Study cooling channel parameters over a range of initial beam momentum and emittance. • Presence of X-rays and electrons from RF cavities and safety issues relating to operation of LH2 absorbers affects specification of tracker. • Solution chosen – Scintillating Fibres readout with VLPCs.

27. Fermilab MICE Responsibilities • Scintillating Fibre Tracker: • Fibre Mirroring • Ribbon fabrication • Connector polishing • VLPC readout system: • VLPC cassettes • Cryostats (4) • AFEIIt • VLSB • Software: • G4MICE • DAQ / Controls and Monitoring • Tracker Quality Assurance

28. MuCool and MICE • Muon Ionization Cooling Experiment (MICE) • Demonstration of “Study II” cooling channel concept • Has Phase I UK funding ($20M) • MuCool Collaboration interface to MICE • Design Optimization/develop of Study II cooling channel • Simulations • Detailed engineering • Full component design • Systems integration • Safety • RF cavity development, fabrication, and test • Absorber development, fabrication, and test • Development of beam line instrumentation • MuCool will prototype and test cooling hardware including MICE pieces for which the collaboration is responsible • Fermilab is also contributing to the cryogenics and readout electronics for the two fiber trackers used in the spectrometers.

29. MERIT N. Mokhov, S. Striganov

30. MERIT –Mercury Intense Target • Test of Hg-Jet target in magnetic field (15T) • Submitted to CERN April, 2004 (approved April 2005) • Located in TT2A tunnel to ISR, in nTOF beam line • First beam ∼April, 2007 • 50 Hz operation at 2.2 GeVÞ 4 MW

31. Fermilab Contribution to MERIT • Developed Full Mars Simulation • Particle fluxes, energy deposition, absorbed dose and residual activity in the experimental hall • Absorbed dose and activation of mercury system • Secondary particle production • Study/define diagnostics needed for experiment • Radiation load in components • Radiation shielding • Particle production in secondary beam

32. Plans for the Remainder of the Year • Design and Simulation • Continue with participation in the International Scoping Study (NF) • NF Front-end detailed simulation • MuCool • After a long pause due to the loss of our 805 MHz RF test facility in Lab G at Fermilab, we are now up and running again • 805 MHz RF studies (with and without B field) • Be Window tests • Materials tests • Surface treatment • 201 MHz RF test program off to a Rousing start! • B field tests • Curved Be Windows • Second round of tests with KEK LH2 convective absorber • Prototype and test encapsulated LiH absorbers RF Highest Priority!

33. Plans for the Remainder of the Year II • MICE • Need to have trackers ready to commission at Rutherford Lab in April 2007. • Purchase fibre and perform mirroring. • Produce ribbons (3 trackers = 45 ribbons ~ 70k fibres). • Produce and commission 2-cassette cryostats. • MERIT • Mars Simulations • Calculate radiation levels in secondary tunnels in order to determine the survivability of electronics • Develop final plan for instrumentation to measure particle fluxes • Scintillation Counters • Cerenkov