Overview of Experiment and Parameter Choices presented by Giles Barr

Outline The ionization cooling technique: –Why we want to use it. –What is it ? Component parameter choices in design MICE measurement program (brief) Detectors in MICE

Why do we want to cool muons? Present day accelerators are used with stable particles only: e , e +, p, ions etc... Aim is to develop technology to allow muons to be accelerated Muons are created in collisions of protons and nuclei which produce pions. These then decay to produce the muons But, the muons are not in an ordered bunch

Large emittance away from a focus Large emittance close to a focus Small emittance x z

Emittance Beta-function (at a focus) Liouville’s theorem Focusing x z

How does ionization cooling work ? Muon lifetime = 2.2 x s so we must be quick Require (1) r.f., (2) absorber and (3) magnetic field x z

The MICE Experiment

Muon cooling formula Beta function Absorber material Ionization Loss (Cooling) Multiple Scattering (Heating) Equilibrium emittance

Choice of material Material  dE/dx  min (MeV g –1 cm 2 ) X 0 (g cm –2 ) Merit Liquid H Liquid He Li Be Al Plastic2.417 a) a) 0.20 a) a) Evaluated for CH 4.

Parameter choices LH 2 Material with the best merit factor by far Thin aluminum windows Multiple scattering also in windows Something light Not reacting with hydrogen B field strength Good   Cell length Short and compact (   ) Good   Radial spaceSuperconducting magnet design limited by field at conductor – easier if coils are close RF gradientReplace energy lost Flip modeFlips required somewhere in cooling channel

Operation 4T 0 -4T 5T 0 SFOFO flip mode No-flip mode

Summary of operating mode variations Change mode of flip operation –flips in all three, –flips in only one magnet, –no flips Different materials: –LH 2, LHe, Li, Be, Al, Plastic Different field settings –‘Central momentum’ values –  T values

Detectors in MICE a brief look Detectors: Spectrometer magnets Scintillating fibres, VLPDs Cerenkov, TOF, calorimetry (=photomultipliers)

Summary Description of the ionization cooling technique Component parameter choices in design MICE measurement programme (brief) Detectors in MICE