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 COLLIDERNeutrino 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?

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Linear accelerator

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π

H- ion Al2O3 foil

Synchrotron accelerator

ProtonTi

target

Pion

Dipole

Decay solenoid

μ

MICEν

MuonNeutrino

ν -

The MICE beamline

Measure Cool Accelerate Cool Accelerate Cool Measure

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!