Overview of Experiment and Parameter Choices presented by Giles Barr.
Published byModified over 5 years ago
Presentation on theme: "Overview of Experiment and Parameter Choices presented by Giles Barr."— Presentation transcript:
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 10 -6 s so we must be quick Require (1) r.f., (2) absorber and (3) magnetic field x z
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 2 4.03461.281 Liquid He1.93794.320.55 Li1.63982.760.30 Be1.59465.190.18 Al1.61524.010.02 Plastic2.417 a) 46.22 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
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