Ken Peach Particle Physics Department Neutrino Factory Overview

Ken Peach A neutrino factory is … … a medium energy[10 GeV  50 GeV] … high Intensity[>10 20 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 … designed to measure the CP/T-violating phase in the MNS matrix with good precision

Ken Peach Muon Storage Ring A neutrino factory is … … an accelerator complex designed to produce >10 20 muon decays per year directed at a detector thousands of km away Principal Components High Power H - source Proton Driver TargetCapture Cooling Muon Acceleration ‘near’ detector ( km) ‘far’ detector ( km) ‘local’ detector

Ken Peach 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?

Ken Peach The Neutrino Factory CPV: > muon decays Conventional beams  & K decay Some flavour selectivity Contamination Fluxes ~ Reactor beams Pure e Huge Fluxes Very low energy (MeV) Super Conventional beams  (& some  decay Flavour selectivity (  ) Low Contamination at E<200MeV Fluxes ~  The Neutrino Factory

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

Ken Peach Neutrino matter-antimatter asymmetry L/E

Ken Peach Matter v. CP-violation effects

Ken Peach A neutrino factory provides … flavour tagged background free normalised (calibrated flux) equal flux beams of muon antineutrinos and electron neutrinos from  + muon neutrinos and electron antineutrinos from  - In principle, gives a complete set of measurements e,   x disappearance  e   appearance  e,    appearance and     charge conjugate

Ken Peach 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

Ken Peach Where could a neutrino factory be built? FNAL BNL CER N GSI CEA INFN JHF DUBNA RAL?

Ken Peach Possible Baselines Gruber

Ken Peach Proton or H - Source and Proton Driver Pion production in the MeV region is essentially proportional to the beam power over a wide range of proton energies –1-5 MW beam power required for  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

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

Ken Peach The proton power of a neutrino factor

Ken Peach Pion Source & Decay Channel Solenoid option – alternative magnetic horn

Ken Peach 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 !

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

Ken Peach PULSED EFFECTS Proton beam pulse length (~1 ns) at 100 Hz rate.  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. Slow target rotation - areas illuminated by pulses overlap 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

Ken Peach POWER DISSIPATION Roger Bennett, Chris Densham & Paul Drumm

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

Ken Peach One Challenge: Ionization Cooling PTPT PLPL After ionisation energy loss After Multiple Scattering After Acceleration Muon Momentum

Ken Peach Heating and Cooling Zisman Ionization loss Multiple scattering

Ken Peach Muon Ionisation Cooling Experiment

Ken Peach 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

Ken Peach Ionisation loss Zisman

Ken Peach 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

Ken Peach  - STEP I: 2004 STEP II: summer 2005 STEP III: winter 2006 STEP IV: spring 2006 STEP V: fall 2006 STEP VI: 2007 Blondel

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

Ken Peach 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

Ken Peach Muon Storage Ring A design (CERN) Haseroth

Ken Peach Cost breakdown - subsystems FNAL Feasibility study

Ken Peach Where could a neutrino factory be built? FNAL BNL CER N GSI CEA INFN JHF DUBNA RAL?

Ken Peach Neutrino Factory Neutrino Factory Footprint

Ken Peach Encouragement Research Fortnight, 15 th January 2003 “Hosting a global facility like the neutrino factory would bring substantial scientific and commercial benefits to the UK” “We believe that an ambitious and far sighted approach is needed to secure maximum benefit for UK science” ‘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’ House of Commons Science and Technology Select Committee. First Report on the work of PPARC, 17 th December 2002

Ken Peach 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