MICE hydrogen review Introduction to MICE

After the LHC… Many open questions in physics: Gravity & standard model Matter-antimatter imbalance Dark matter Higher energy collisions = MUON COLLIDER Neutrino physics = NEUTRINO FACTORY MICE is an essential proof-of-concept for both

Muon Ionization Cooling Experiment MC & NF need collimated muon beam Pion decay produces muon beam with high ‘emmitance’ Traditional ‘cooling’ techniques are too slow... MICE uses ionization of an absorber material to reduce momentum in all directions Beam then reaccelerated in z-direction only

π – μ – ν? Linear accelerator π H- ion Al 2 O 3 foil Synchrotron accelerator Proton Ti target Pion Dipole Decay solenoid μ MICE ν Muon Neutrino ν -

The MICE beamline MeasureCoolAccelerateCoolAccelerateCoolMeasure Absorber focus coil Spectrometer solenoid Radio frequency coupling coil

Why hydrogen? Because physicists like to be difficult. And, because it has the best ratio of ionisation cooling to multiple scattering (or so they say) Lithium hydride and plastic will also be used

Small problem number 1 We apparently forgot that iron becomes magnetic in a magnetic field… All the services positioned ‘safely’ behind the shield walls became suddenly not so safe! Two options: – Shield every sensitive component individually with mu-metal and iron – Build a retrospective return yoke This has been plagued by: - Difficult integration engineering - Stubborn procurement departments - US/Japan cultural differences - Snow But it’s now on its way!

Small problem number 2 The US Muon Accelerator Program was cancelled and MICE was ordered to undergo a managed ramp-down in DOE funding Taking into account the outstanding US contribution and STFC’s remaining commitment, MICE was re-configured to: Fortuitously, this is actually a good thing as it is now more relevant to future NF activities!