Neutrino Factory Overview Ken Peach Particle Physics Department

Neutrino Factory Overview Ken Peach Particle Physics Department

A neutrino factory is … … a medium energy [10 Ge. V 50 Ge. V] … 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 matrix with good precision Ken Peach

A neutrino factory is … 20 … an acceleratorcomplex designed to produce >10 muon decays per year directed at a detector thousands of km away Principal Components High Power H- source Proton Target Driver Capture ‘far’ detector (5000 -8000 km) Cooling Muon Storage Ring ‘local’ detector Muon Acceleration ‘near’ detector (1000 -3000 km) 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: > 1020 muon decays Conventional n beams p, m & K decay Some flavour selectivity Contamination Fluxes ~1017 -1018 n Reactor n beams Pure ne Huge Fluxes Very low energy (Me. V) Super Conventional n beams p, (& some m) decay Flavour selectivity (nm) Low Contamination at E<200 Me. V Fluxes ~1018 -1019 n? 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 m+ muon neutrinos and electron antineutrinos from m. In principle, gives a complete set of measurements n e, n m n x ne nm n e, n m n t m+ m- disappearance 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 • (~1000 km, ~3000 km or ~3000 km, ~6000 km) • 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 R L? A DUBNA JHF CERN GSI CEA INFN Ken Peach

Possible Baselines Gruber Ken Peach

Proton or H- Source and Proton Driver • Pion production in the 200 - 400 Me. V 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 – m. A proton currents required • Proton energy is a critical design choice – Ideas at 2. 2 Ge. V (CERN), 5 Ge. V (RAL), 8 & 16 Ge. V (FNAL), 15 Ge. V (CERN), 24 Ge. V (BNL), 50 Ge. V (JHF) – ‘figure of merit’ is probably • pions per steradian per proton per Ge. V – Part of the overall design optimisation • Need better data on pion production – HARP, E 910 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/Nu. MI • PSI, TRIUMF & KEK/muon sources – clear area for R&D Mohkov (FNAL) • material • radiation & heating >1 era T d Ra ! Ken Peach

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-away section of target material) Shock wave stresses Shock wave stress intensity contours 4 µs after 100 k. J, 1 ns proton pulse Roger Bennett, Chris Densham & Paul Drumm Ken Peach

PULSED EFFECTS Slow target rotation - areas illuminated by pulses overlap 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. 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 1 10 3 1000 m 100 m 200 m 10 m 2000 m v = 20 m/s 1000 m v = 10 m/s 10 power v = 100 m/s 10000 m 100 m v = 1 m/s MW 1 2 m 1 m 0. 1 10 m v = 0. 1 m/s 1 m 10 m 1 m 0. 1 m 0. 01 0. 1 m 1 Roger Bennett, Chris Densham & Paul Drumm 10 radius/velocity 100 1 10 3 Ken Peach

Cooling • Cooling will (probably) work … but experiments needed pions longitudinal phase space at production. (fluka calculation, 26 mm mercury target, 2. 2 Ge. V beam) Lombardi Ken Peach

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

Heating and Cooling tio s los n Io a niz Mu ltip le sc att e rin g Zisman Peach Ken

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 Peach Ken

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 v Emittance: 1πmm. mrad to 50 πmm. mrad v Energy: 100 to 400 Me. V v Energy spread: “zero” to 20% v Phase, B-field, etc? • Use a single particle beam Ken Peach

m - 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

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

Muon Acceleration • 2 or 3 stages – Linac (to 1 2 Ge. V? ) – Recirculating linac 1 (to 10 Ge. V? ) – Recirculating linac 1 (to final energy) • Some possible parameters (CERN) Haseroth Ken Peach

Muon Storage Ring • A design (CERN) Haseroth Ken Peach

FNAL Feasibility study Cost breakdown - subsystems Ken Peach

Where could a neutrino factory be built? FNAL BNL R L? A DUBNA JHF CERN GSI CEA INFN Ken Peach

Neutrino Factory Footprint Ken Peach

Encouragement Research Fortnight, 15 th January 2003 House of Commons Science and Technology Select Committee. First Report on the work of PPARC, 17 th 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” Ken Peach

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