International Muon Ionization Cooling Experiment
Encyclopedia
The International Muon Ionization Cooling Experiment (or MICE) is a high energy physics
experiment
dedicated to observing ionization cooling
of muon
s for the first time. This is a process where by the beam emittance
of a beam is reduced in order to reduce the beam size, so that more muons can be accelerated in smaller aperture accelerators and with fewer focussing magnets. This might enable the construction of high intensity muon accelerators, for example for a Neutrino Factory
or Muon Collider.
MICE will reduce 6D emittance over a single 5.5 m cooling cell and measure that reduction. The MICE design is based on a scheme outlined in Feasibility Study II. Pions will be produced from a target in the ISIS neutron source
and transported along a beamline where most will decay to muons before entering MICE. MICE will measure cooling performance over a range of beam momenta between about 150 and 250 MeV/c, for various absorber materials and magnetic field configurations.
The MICE linacs consist of four normal-conducting copper cavities approximately 430 mm in length and 610 mm in radius. The RF cavities operate at 201.25 MHz with a peak field of 8 MV/m. The full muon energy will be replaced for muons that pass through the rf cavities on-crest. As there is no time distribution in the incoming beam, muons at all phases will be sampled.
The cavities must have a large aperture in order to avoid significant scraping from the high emittance beam. Hence 0.38 mm thick Beryllium windows are used to electromagnetically seal the cavities to avoid a high shunt impedance. These are nearly invisible to the muon beam. The windows have been designed to prevent electromagnetic heating from buckling the windows.
The baseline MICE absorber consists of a 21 litre, 350 mm long liquid Hydrogen vessel sealed with a pair of curved, cylindrically symmetric aluminium windows at each end and cooled using cryocoolers. The absorber is removable, so that different materials may be used. For example, solid absorbers constructed from materials such as Lithium Hydride may replace the liquid Hydrogen absorbers.
in the UK. The muon beamline is in place and commissioning has begun. During the rest of 2010 further instrumentation will be installed and commissioned. Starting in 2011 and until 2014, measurements with progressively more powerful muon cooling devices will aim at effecting the first experimental demonstration of ionization cooling itself.
Compare to: MUCOOL
Particle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
experiment
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
dedicated to observing ionization cooling
Ionization cooling
Ionization cooling is a process by which the beam emittance of a beam of particles may be reduced.In ionization cooling, particles are passed through some material. The momentum of the particles is reduced as they ionize atomic electrons in the material. Thus the normalised beam emittance is reduced...
of muon
Muon
The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...
s for the first time. This is a process where by the beam emittance
Beam emittance
The beam emittance of a particle accelerator is the extent occupied by the particles of the beam in space and momentum phase space as it travels. A low emittance particle beam is a beam where the particles are confined to a small distance and have nearly the same momentum...
of a beam is reduced in order to reduce the beam size, so that more muons can be accelerated in smaller aperture accelerators and with fewer focussing magnets. This might enable the construction of high intensity muon accelerators, for example for a Neutrino Factory
Neutrino Factory
The Neutrino Factory is a proposed particle accelerator complex intended to measure in detail the properties of neutrinos, which are extremely weakly interacting fundamental particles that can travel in straight lines through normal matter for thousands of kilometres...
or Muon Collider.
MICE will reduce 6D emittance over a single 5.5 m cooling cell and measure that reduction. The MICE design is based on a scheme outlined in Feasibility Study II. Pions will be produced from a target in the ISIS neutron source
ISIS neutron source
ISIS is a pulsed neutron and muon source. It is situated at the Rutherford Appleton Laboratory on the Harwell Science and Innovation Campus in Oxfordshire, United Kingdom and is part of the Science and Technology Facilities Council...
and transported along a beamline where most will decay to muons before entering MICE. MICE will measure cooling performance over a range of beam momenta between about 150 and 250 MeV/c, for various absorber materials and magnetic field configurations.
Beamline
The MICE muon beamline provides a low intensity muon beam for MICE. Pions will be transported from a target dipping into the fringe of the ISIS proton beam, through a pion decay channel, into a muon transport line and then into MICE. For efficient use of muons it is desirable to have a reasonably good match between the transport beamline and the cooling channel, with selection performed in analysis. Also, the beamline must suppress non-muon events from entering the cooling channel. A beam rate of a few hundred muons per second is expected.Cooling Channel
The final MICE magnetic lattice is made up of 18 superconducting coils. Three solenoid coils provide a constant field for the each of the two MICE tracking detectors and matching coils match the beam from the spectrometers into, and out of, the cooling channel. Each of the three absorbers sits between two focus coils. These focus the muon beam in the absorbers to provide optimal cooling. At the centre of each RFCC module a single coupling coil creates the second harmonic term in the field that improves the range of momenta that the cooling channel can accept.The MICE linacs consist of four normal-conducting copper cavities approximately 430 mm in length and 610 mm in radius. The RF cavities operate at 201.25 MHz with a peak field of 8 MV/m. The full muon energy will be replaced for muons that pass through the rf cavities on-crest. As there is no time distribution in the incoming beam, muons at all phases will be sampled.
The cavities must have a large aperture in order to avoid significant scraping from the high emittance beam. Hence 0.38 mm thick Beryllium windows are used to electromagnetically seal the cavities to avoid a high shunt impedance. These are nearly invisible to the muon beam. The windows have been designed to prevent electromagnetic heating from buckling the windows.
The baseline MICE absorber consists of a 21 litre, 350 mm long liquid Hydrogen vessel sealed with a pair of curved, cylindrically symmetric aluminium windows at each end and cooled using cryocoolers. The absorber is removable, so that different materials may be used. For example, solid absorbers constructed from materials such as Lithium Hydride may replace the liquid Hydrogen absorbers.
Detectors
Muons pass through the cooling channel one by one. The muons' phase space coordinates will be measured by time of flight scintillators and scintillating fibre tracking detectors upstream and downstream of the cooling channel. Muons will be distinguished from other particles in the beam using a combination of the spectrometers and the so-called Particle Identification (PID) detectors, three time of flight scintillators, a Cerenkov detector and an electron-muon calorimeter.Status
As of 2010, MICE is in the final stages of construction at Rutherford Appleton LaboratoryRutherford Appleton Laboratory
The Rutherford Appleton Laboratory is one of the national scientific research laboratories in the UK operated by the Science and Technology Facilities Council . It is located on the Harwell Science and Innovation Campus at Chilton near Didcot in Oxfordshire, United Kingdom...
in the UK. The muon beamline is in place and commissioning has begun. During the rest of 2010 further instrumentation will be installed and commissioned. Starting in 2011 and until 2014, measurements with progressively more powerful muon cooling devices will aim at effecting the first experimental demonstration of ionization cooling itself.
Compare to: MUCOOL