Neutrino Factory Overview

1. Neutrino Factory Overview

2. A neutrino factory is … … a medium energy [10 GeV  50 GeV] … high Intensity [>1020 muon decays/year] … muon storage ring [racetrack, triangle, bow-tie] … with long straight section(s) … pointing to detector(s) several thousand km distant … designed to measure the CP/T-violating phase in the MNS matrixwith good precision

3. A neutrino factory is … Target Capture Proton Driver … an accelerator complex designed to produce >1020 muon decays per year directed at a detector thousands of km away Principal Components High Power H- source ‘far’ detector (5000-8000km) Muon Storage Ring Cooling Muon Acceleration ‘local’ detector ‘near’ detector (1000-3000km)

4. Why? • Neutrino physics has become a very hot topic • Fundamental particle • Recent observations show that neutrinos are not massless • Neutrino masses are “something new” • Physics “beyond the standard model” • Implications for cosmology • Possible (part of the) explanation for the matter/antimatter asymmetry of the Universe • Why is there a physical universe at all?

5. The Neutrino Factory CPV: > 1020 muon decays Conventional n beams p,m & K decay Some flavour selectivity Contamination Fluxes ~1017-1018n Reactor n beams Pure ne Huge Fluxes Very low energy (MeV) Super Conventional n beams p, (& some m) decay Flavour selectivity (nm) Low Contamination at E<200MeV Fluxes ~1018-1019n? The Neutrino Factory

6. Neutrino Mixing Parameters of neutrino oscillation 1 absolute mass scale 2 squared mass differences 3 mixing angles 1 phase 2 Majorana phases

7. Neutrino matter-antimatter asymmetry L/E

8. Matter v. CP-violation effects

9. A neutrino factory provides … flavour tagged background free normalised (calibrated flux) equal flux beams of muon antineutrinos and electron neutrinos from m+ muon neutrinos and electron antineutrinos from m- In principle, gives a complete set of measurements ne, nm nxdisappearance ne  nmappearance ne, nm  nt appearance and m+ m-charge conjugate

10. Shape of Muon Storage Ring • Racetrack • Single far detector, relatively simple construction • Maximum ‘efficiency’ ~ 40% • Very intense local beam for conventional neutrino experiments • Triangle • Two detectors at different distances • (~1000km, ~3000km or ~3000km, ~6000km) • Maximum ‘efficiency’ ~80% • Ring built in a steeply inclined plane • Steeply rising local beam for conventional neutrino experiments • Bow-tie • Advantages as for triangle • Because of the ‘bow-tie’, the depth is ~½ triangle depth • 2 Steeply rising local beams for conventional neutrino experiments • May ruin the precision knowledge of the neutrino spectrum

11. Where could a neutrino factory be built? DUBNA FNAL BNL JHF CERN GSI CEA INFN RAL?

12. Possible Baselines Gruber

13. Proton or H- Source and Proton Driver • Pion production in the 200 - 400 MeV region is essentially proportional to the beam power over a wide range of proton energies • 1-5 MW beam power required for 1020 1021 muons per year • mA proton currents required • Proton energy is a critical design choice • Ideas at 2.2 GeV (CERN), 5 GeV (RAL), 8 & 16 GeV (FNAL), 15 GeV (CERN), 24 GeV (BNL), 50 GeV (JHF) • ‘figure of merit’ is probably • pions per steradian per proton per GeV • Part of the overall design optimisation • Need better data on pion production • HARP, E910

14. Example: Proton Driver Design Similar features needed for • ESS • Radioactive Ion Beams • Accelerator Transmutation of Nuclear Waste • IFMIF Prior & Rees

15. The proton power of a neutrino factor

16. Pion Source & Decay Channel Solenoid option – alternative magnetic horn

17. Target issues/muon source • Liquid jet … or … solid (moving?) target • no clear consensus • much R&D needed • Existing/future high power targets • RAL/ISIS • CERN/ISOLDE • CERN & FNAL/antiproton • SNS/Oak Ridge • FNAL/NuMI • PSI,TRIUMF & KEK/muon sources • clear area for R&D • material • radiation & heating Mohkov (FNAL) >1 Tera Rad !

18. Target Studies for a Future Neutrino Factory Pion production target for a future neutrino factory: Pulsed proton beam induced shock waves in section of solid tantalum target Proposed rotating tantalum target ring Temperature jump (cut-awaysection of target material) Shock wave stresses Shock wave stress intensity contours 4 µs after 100 kJ, 1 ns proton pulse Roger Bennett, Chris Densham & Paul Drumm

19. PULSED EFFECTS Proton beam pulse length (~1 ns) at 100 Hz rate. Slow target rotation - areas illuminated by pulses overlap  rotation individual overlapping beam pulses on the target, 20 cm long Faster rotation, illumination by each pulse separate until at v = 20 m/s they just touch. At speeds greater than 20 m/s the areas of each pulse separate The maximum power at a pulse repetition rate f is: W = 0.322·f W = 32 MW at 100 Hz Roger Bennett, Chris Densham & Paul Drumm

20. POWER DISSIPATION 3 1 10 v = 100 m/s 10000 m 1000 m 100 v = 20 m/s 2000 m 100 m 200 m v = 10 m/s 1000m 10 power MW 20 m 100 m 10 m v = 1 m/s 10 m 100 m 2 m 1 10 m v = 0.1 m/s 1 m 1 m 10 m 0.1 1 m 0.1 m 0.1 m 0.01 3 radius/velocity 0.01 0.1 1 10 100 1 10 Roger Bennett, Chris Densham & Paul Drumm

21. Cooling pions longitudinal phase space at production. (fluka calculation, 26 mm mercury target, 2.2 GeV beam) Lombardi • Cooling will (probably) work … but experiments needed

22. One Challenge: Ionization Cooling PT PL Muon Momentum After Multiple Scattering After ionisation energy loss After Acceleration

23. Heating and Cooling Ionization loss Multiple scattering Zisman

24. Muon Ionisation Cooling Experiment

25. ISIS as MICE host HEP Test Beam Hall Potential MICE location An international study of muon beam options (including CERN, FNAL, TRIUMF, PSI) ISIS was identified as the best technical location for the MICE test facility

26. Ionisation loss Zisman

27. Muon Ionisation Cooling Experiment What does it have to do? • Demonstrate a cooling channel is feasible • Measure a 10% reduction in emittance • Investigate channel performance as a function of • Emittance: 1πmm.mrad to 50 πmm.mrad • Energy: 100 to 400 MeV • Energy spread: “zero” to 20% • Phase, B-field, etc? • Use a single particle beam

28. m - STEP I: 2004 STEP II: summer 2005 STEP III: winter 2006 STEP IV: spring 2006 STEP V: fall 2006 STEP VI: 2007 Blondel

29. Reverse Rotation Lattice An alternative to cooling? Pion-muon decay channel 88 MHz muon linac Chris Prior, Graham Rees

30. Muon Acceleration • 2 or 3 stages • Linac (to 1  2 GeV?) • Recirculating linac 1 (to 10 GeV?) • Recirculating linac 1 (to final energy) • Some possible parameters (CERN) Haseroth

31. Muon Storage Ring • A design (CERN) Haseroth

32. Cost breakdown - subsystems FNAL Feasibility study

33. Where could a neutrino factory be built? DUBNA FNAL BNL JHF CERN GSI CEA INFN RAL?

34. Neutrino Factory Neutrino Factory Footprint

35. Encouragement Research Fortnight, 15th January 2003 House of Commons Science and Technology Select Committee. First Report on the work of PPARC, 17th December 2002 “Hosting a global facility like the neutrino factory would bring substantial scientific and commercial benefits to the UK” ‘the government will need to show “greater willingness” … to carry out the necessary development work to put together a serious bid, and then commit the necessary resources … to see it through’ “We believe that an ambitious and far sighted approach is needed to secure maximum benefit for UK science”

36. A neutrino factory … … is needed (probably) to measure CP violation in the lepton sector … is (probably) feasible … but significant challenges Design – muon energy, baseline optimisation Machine – target, cooling, r/f (muon acceleration) Detector – flavour identification with charge measurement … and COST