1. Neutrino Factories and Muon Ionization Cooling Channels D. Errede HETEP University of Illinois 17 March, 2003

2. 2 Why build a Neutrino Factory? (Physics, of course) What does a Neutrino Factory look like? In particular, what is an ionization cooling channel? What has the University of Illinois been doing with respect to a cooling channel?

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4. 4 The Physics of Neutrinos Neutrino masses (pattern of the all fermion masses) Neutrino oscillation parameters (fill in the CKM matrix for leptons) CP Violating processes in the Lepton Sector (origin of baryon-antibaryon asymmetry in our universe?) GUTS: relating properties of quarks and leptons Is there a grand unified scheme?

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6. 6 The Physics of Neutrinos Standard form for Mixing Matrix connecting weak and mass eigenstates        are the 4 real parameters that describe the mixing…  0 implies CP violation. (phase between 0 and 2 

7. 17 March, 2003 7 The Physics of Neutrinos Connect two weak eigenstates with the evolution operator – involves Hamiltonian H 0 Use two assumptions: m1 < m2 << m3 and dM 2 = dm 2 atm = dm 2 32 ~ dm 2 31 we get And something similar but more complicated for 

8. 17 March, 2003 8 The Physics of Neutrinos The sign of  m 2 : solar neutrinos Matter effects : MSW (Mikheev, Smirnov, Wolfenstein) e interacts with electrons in matter through the charged current interaction. This adds a term to the evolution operator. There is a resonance in matter near a = 1 for typical values of sin 2 2  (10 -3 - 10 -2 ) “a” depends on N e, G F, E,  m 2.  =  12,  13

9. 17 March, 2003 9 The resonance applies to neutrinos for positive dm 2 and antineutrinos for negative  m 2. Thus we can get the mass hierarchy. -----m3 -----------m2 -----------m1 OR -----------m2 -----------m1 -----m3 The Physics of Neutrinos

10. 17 March, 2003 10 The Physics of Neutrinos 3 Plausible Sets of Values 1 2 3 J - Jarlskog factor a measure of CP violatioin

11. 17 March, 2003 11 J = c 12 c 13 2 c 23 s 12 s 13 s 23 sin  Jarlskog J-factor a measure of CP violation CP Operation: C( e L ) = e L P( e L ) = e R CP Violating Process: For example: in vacuum … The Physics of Neutrinos : CP VIOLATION

12. 17 March, 2003 12 The Physics of Neutrinos CP Violating Processes in the Lepton Sector Why is this interesting/fun/exciting? A possible explanation for Baryogenesis. (So far CP violating processes in the b quark sector are insufficient to explain baryogenesis) A SCENARIO Heavy Neutral Leptons: Majorana neutrinos through see-saw mechanism produces a light neutrino pair and a heavy neutrino pair. N e- H+ or e+ H- (both massless particles because this is occuring before EW symmetry breaking).

13. 17 March, 2003 13 The Physics of Neutrinos N e- H+ or e+ H- CP Violating processes provides excess of e +,  ,  + over e -,  ,  - before EW phase transition. Andrei Sakharov says we also need non-equilibrium conditions so that these processes are not driven to equalize the numbers. Standard Model nonperturbative processes violate B, L, but conserve B-L. Churns lepton+’s into baryon material. Thank you Boris Kayser

14. 17 March, 2003 14 The Physics of Neutrinos CP Violation in the Lepton Sector What would this have to do with CP violating processes in the low mass neutrino sector? We don’t know, but certainly CP violation in leptons at low mass makes CP violation in leptonic interactions at high mass scales more plausible. GUTs: one can also imagine unifying quarks and lepton such that their CKM matrices are also related. We won’t understand this until all the parameters are measured.

15. 17 March, 2003 15 Neutrino Factory 1.High intensity beam on target to produce particles (  ’s) for a secondary beam. - Proton Driver + Target 2.Collects  ’s, allow them to decay into muons, spread bunch (large  E) and then perform phase rotation – Drifts + Induction Linacs 3.Reduce energy (and emittance) between induction linacs – Minicooling 4. Adiabatically change from one lattice to the next lattice – Matching Sections 5.Divide long bunch (~100 m) into short bunches that cooling section can handle - Buncher

16. 17 March, 2003 16 Neutrino Factory 6.Reduce beam emittance – Cooling Channels 7.Accelerate to energy and emittance size that the next recirculating accelerators can handle - Linac 8.Accelerate from 2.8 GeV to 20 GeV – Recirculating Linear Accelerators (RLA’s) 9.Circulate muons and let some decay on production straight – Muon Storage Ring 10.Make measurements on neutrino interactions – Near and Far Detectors

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18. 17 March, 2003 18 Neutrino Factory: Proton Driver Based on Feasibility Study 2 version of a neutrino factory…hence set at Brookhaven Natl Lab AGS proton driver uses existing ring, bypasses existing booster and introduces 3 new superconducting linacs.

19. 17 March, 2003 19 Neutrino Factory: AGS Proton Driver Parameters Total beam power (MW)1 Beam Energy (GeV)24 Average beam current (  A) 42 Cycle time (ms)400 Number of protons per fill1 x 10 14 Average circulating current6 No. of bunches per fill6 No. of protons per bunch1.7 x 10 13 Time between extracted bunches (ms)20 Bunch length at extraction, rms (ns)3 Peak bunch current (A)400 Total bunch area (eV-sec)5 Bunch emittance, rms (eV-sec)0.3 Momentum spread, rms0.005

20. 17 March, 2003 20 AGS Proton Driver Layout To target station High Intensity Source plus RFQ 116 MeV Drift Tube Linac (first sections of 200 MeV Linac) Superconducting Linacs 400 MeV 800 MeV 1.2 GeV Booster AGS 1.2 GeV 24 GeV 0.4 s cycle time (2.5 Hz) 6 bunches

21. 17 March, 2003 21 Neutrino Factory: Superconducting Linacs Period Cryo-Modules Insertion at room temp C D AB cavity A B Topology of a Period C D Configuration of the cavities within the cryo-modules

22. 17 March, 2003 22 Injection turns360 Repetition rate (Hz)2.5 Pulse length (ms)1.08 Chopping rate (%)65 Linac average/peak current (mA) 20/30 Momentum spread+/- 0.0015 Norm. 95% emittance (  m rad) 12 RF Voltage (kV)450 Bunch length (ns)85 Longitudinal emittance (eV-s)1.2 Momentum spread+/- 0.0048 Norm. 95% emittance (  m rad) 100 AGS Injection Parameters

23. 17 March, 2003 23 AGS Proton Driver AGS : Harmonic 24 18 bunches Bunch pattern for using harmonic 24 to create 6 bunches

24. 17 March, 2003 24 Neutrino Factory : Target Energy on target 24 GeV, baseline beam power 1 MW, Pion momentum distribution peaks at 250 MeV, = 150 MeV  large angles coming off target…. Capture with 20 Tesla solenoid (r = 7.5cm, p Tmax = 225 MeV). Actually a horn which “tapers” to 1.25 T (r= 30cm, p Tmax = 67.5 MeV) (A horn converts transverse momentum into longitudinal momentum.) Target: High Z  maximize yield of  /p Goal of 2 10 20 muon per year ( 10 7 seconds) decaying in detector direction, 50 kT, 1800 km away.

25. 17 March, 2003 25 Neutrino Factory : Target Z

26. 17 March, 2003 26 Neutrino Factory : Target Liquid Hg jet target chosen for maximum yield. Need to handle 1 – 4 MW beams. Want v jet = 30m/s to resupply Hg. Tests achieved 2.5 m/s to date. ( 30m/s only resupplies mercury before next bunch on average – 6 x 2.5 Hz = 15/sec )

27. 17 March, 2003 27 Target R&D for MW-Scale Proton Beams Carbon Target tested at AGS (24 GeV, 5E12 ppp, 100ns) –Probably OK for 1.5 MW beam … limitation: target evaporation Target ideas for 4 MW: Water cooled Ta Spheres (P. Sievers), rotating band (B. King), conducting target, Front-runner = Hg jet 13 Tesla CERN/Grenoble Liquid Hg jet tests in 13 T solenoid – Field damps surface tension waves 0 Tesla BNL E951: Hg Jet in AGS beam – Jet (2.5 m/s) quickly re-establishes itself. Will test in 20T solenoid in future. t = 0 0.75 ms 2 ms 7 ms 18 ms 27

28. 17 March, 2003 28 Neutrino Factory : Drifts and Induction Linacs Beam has large energy spread. Drift allows beam to spread out to a long bunch length. Induction linacs accerlate late muons (lower energy) and decelerate early muons (higher energy).

29. 17 March, 2003 29 Neutrino Factory : Drifts and Induction Linacs

30. 17 March, 2003 30 Neutrino Factory : Drifts and Induction Linacs

31. 17 March, 2003 31 Neutrino Factory : Drifts and Induction Linacs

32. 17 March, 2003 32 Neutrino Factory : Drifts and Induction Linacs

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34. 17 March, 2003 34 Neutrino Factory : Drifts and Induction Linacs

35. 17 March, 2003 35 Neutrino Factory : Minicooling in Drifts and Induction Linacs

36. 17 March, 2003 36 Neutrino Factory : Buncher and Cooling Channel In order to fit muon beam into cooling lattice the Buncher separates the ~100m long trail of muons into rf buckets. The cooling channel (P nominal = 200 MeV) then reduces the transverse emittance to a level acceptable for acceleration to 20 GeV.

37. 17 March, 2003 37 Momentum-time distributions through the buncher

38. 17 March, 2003 38 Neutrino Factory : Buncher and Cooling Channel

39. 17 March, 2003 39 Momentum-time distributions through the buncher

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41. 17 March, 2003 41 Neutrino Factory : Cooling Channel Lattice Cell

42. 17 March, 2003 42 Neutrino Factory : Cooling Channel

43. 17 March, 2003 43 Neutrino Factory : Cooling Channel

44. 17 March, 2003 44 Neutrino Factory : Cooling Channel

45. 17 March, 2003 45 Neutrino Factory : Cooling Channel

46. 17 March, 2003 46 Neutrino Factory : Cooling Channel

47. 17 March, 2003 47 Neutrino Factory : Cooling Channel

48. 17 March, 2003 48 Neutrino Factory : Cooling Channel

49. 17 March, 2003 49 Absorber : Forced Flow Design

50. 17 March, 2003 50 Approximate Equation Transverse Emittance in a step ds along the particle’s orbit: First term is the Ionization Energy Loss (Cooling) Term Second term is the Multiple Scattering (Heating) term

51. 17 March, 2003 51 Absorber Aluminum Window Pressure/Burst Testing

52. 17 March, 2003 52 MUCOOL: UIUC Absorber Instrumentation Project Zach Conway Mike Haney Debbie Errede

53. 17 March, 2003 53 MUCOOL RF R&D High Power 805 MHz Test Facility 12 MW klystron Linac-type modulator & controls X-Ray cavern 5T two-coil SC Solenoid Dark-current & X-Ray instrumentation Need high gradient cavities in multi-Tesla solenoid field Concept 1 – open cell cavity with high surface field Concept 2 – pillbox cavity - close aperture with thin conducting foil 805 MHz Cavity built & tested ®Surface fields 53 MV/m achieved ®Large dark currents observed ®Breakdown damage at highest gradients ®Lots of ideas for improvement 805 MHz Cavity built & being tested 53

54. 17 March, 2003 54 Neutrino Factory : Cooling Channel

55. 17 March, 2003 55 Construction of FODO Quad Cooling Cell 1/2 1/2 abs F rf D rf F rf D abs COOLING CELL PHYSICAL PARAMETERS: Quad Length0.6 m Quad bore0.6 m Poletip Field~1 T Interquad space0.4 - 0.5 m Absorber length0.35 m * RF cavity length0.4 - 0.7 m* Total cooling cell length4 m *The absorber and the rf cavity can be made longer if allowed to extend into the ends of the magnets. Or, more rf can be added by inserting another FODO cell between absorbers In this design For applications further upstream at larger emittances, this channel can support a 0.8 m bore, 0.8 m long quadrupole with no intervening drift without matching to the channel described here.

56. 17 March, 2003 56 MOVIE Quad cooling movie / Kyoko Makino GSview - View – fit window – full screen – page down - escape Quad Cooling Beam Dynamics Group UIUC – Debbie Errede, Kyoko Makino, Kevin Paul MSU – Martin Berz FERMILAB – Carol Johnstone, A. Van Ginneken

57. 17 March, 2003 57 Recirculating Linear Accelerators (RLAs)

58. 17 March, 2003 58 Recirculating Linear Accelerators (RLAs) : Preaccelerator

59. 17 March, 2003 59 Recirculating Linear Accelerators (RLAs) : Preaccelerator

60. 17 March, 2003 60 Recirculating Linear Accelerators (RLAs) : Preaccelerator

61. 17 March, 2003 61 Recirculating Linear Accelerators (RLAs) : Preaccelerator

62. 17 March, 2003 62 Recirculating Linear Accelerators (RLAs) : Preaccelerator

63. 17 March, 2003 63 Recirculating Linear Accelerators (RLAs) : Preaccelerator

64. 17 March, 2003 64 Recirculating Linear Accelerators (RLAs) : Injection Chicane from Linac to RLA

65. 17 March, 2003 65 Recirculating Linear Accelerators (RLAs) : Arcs

66. 17 March, 2003 66 Recirculating Linear Accelerators (RLAs) : Arcs

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68. 17 March, 2003 68 Recirculating Linear Accelerators (RLAs)

69. 17 March, 2003 69 Recirculating Linear Accelerators (RLAs)

70. 17 March, 2003 70 Muon Storage Ring Maximize number of muon on production straight f s = L s /C Minimize length of arcs Real Estate is an important issue here. Larger energy decreases angular beam spread (1/  ) allowing more neutrinos on “target” = detector

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72. 17 March, 2003 72 Real Estate is an important issue here! : ARCS

73. 17 March, 2003 73 COSY : Kyoko Makino (UIUC), Martin Berz (MSU) Tracking performed on a single arc cell.

74. 17 March, 2003 74 COSY : Kyoko Makino (UIUC), Martin Berz (MSU)

75. Same Lattice with End Fields added

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77. 17 March, 2003 77 Conclusions Neutrino physics is fascinating, beautiful and accessible. A Muon Collaboration exists that has done two feasibility studies on neutrino factory designs and R&D on targetry, absorbers, 800 (200) MHz NCRF cavities, solenoid magnets, and constructing a test area off of the Fermilab 400 MeV/c proton linac. Design studies for Ring Coolers, FFAG machines, Emittance Exchange are ongoing. Alternative technologies pursued at CERN and in Japan. Future plans include the construction of a cooling channel lattice cell to be tested in a low intensity muon beam at Rutherford Labs near Oxford, England.