The Muon Ionisation Cooling
Experiment
David Adey
EPP Group Meeting - Warwick University
20th December 2011
• Muon beam emittance too large for downstream accelerator
• Need fast method to reduce transverse emittance
• Ionisation cooling unproven
2
Ionisation Cooling
• Need for transverse emittance reduction
to meet acceptance in neutrino factory or
muon collider
• Existing methods of cooling too slow for
muons
• Reduce total momentum of beam with
an absorber (some scattering involved) emittance reduction
• Re-accelerate beam longitudinally for
sustainability
• Optimise absorber material and
focussing for lowest equilibrium emittance
PT
Quality Factor - scaled to LH2
PT
PT
MCS
dE/dx
Pz
Initial State
Pz
Pz
Absorber
Acceleration
3
Muon Ionisation Cooling Experiment
• Based at Rutherford Appleton
Laboratory, UK
•Precision single particle
measurements of position, time
and momentum: measure 10%
loss in emittance to 1%
• PID for muon tagging
• Liquid hydrogen absorber
• 201MHz 8MV RF cavities
• Staged data campaign
4
Steps
Step I - Installation of detectors and characterisation of
beamline - Complete
Step IV - Installation of trackers and
absorber. Precision measurement of
emittance reduction
Step V - Installation of first RF
cavities - Sustainable cooling
Step VI - The full
cooling cell
5
Measurement concepts
TOF0
TOF1
TOF2
Tracker 1
Q6
Q7
Tracker 2
Q9
• Trackers in solenoids measure x, Px, y, Py, t, Pz
• Measure beam parameters is Tracer 1
Cooling
• Beam passes through cooling channel
Channel
• Remeasure in Tracker 2 and compare
6
MICE at RAL
7
Target
• Dynamic target - mechanically dips
into Isis beam at extraction - 80g
acceleration
• ~ 1Hz rate/1ms spill
• Depth limited to beam losses in Isis
• Rates in MICE hall proportional to
losses seen in Isis
Average Tracks per 1ms spill
Average Tracks per 3.2ms spill
16
50
0
2.5
Beamloss (V.ms)
0
3.5
Beamloss (V.ms)
8
2011 Progress
• Tests of EMR detector - calorimeter to detect muons that
have decayed in the beamline - now returned to Geneva
• Upgrade of Cerenkov detectors
• Improvement of TOF detectors - 50ps resolution
• Installation of RF power system - 1MW achieved
• More Step 1 data
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TOF0
Q4
Q5
Q5
Step 1 data campaign
TOF1
Q6
Q7
TOF2
Q9
Cooling
Channel
• Detector installation and commissioning
• Vary beamline settings
• Measure particle position and time at TOF counters
• Reconstructed position and momentum
• Calculate mean parameters at entrance of cooling channel
• > 1TB of data taken so far - interruptions due to Isis cycle and target
problems
10
• Time of flight detectors used for
measurement of particle position
and angle
• Emittance and betatron function
of beams measured
• Preliminary measurement using
TOFs - precision measurement
requires spectrometers
11
SciFi Trackers
• 5 Stations (measurement planes)
• Each station has 3 planes of
scintillating fibre at 120 degrees
• Fibres 350microns thick in
doublet layer arrangement
• Placed within solenoid particles follow helical motion
• Pt and Pz from helix radius and
dip angle
• VLPC and D0 CFT Front end
electronics
Tracker 1
Measure emittance in
Cooling channel
Tracker 2
Measure emittance out
12
• Data acquisition developed
• Triggering and Timing
• Calibration
13
• Hardware seems to have
remained stable
• Issues remain in readout
• Plane single station test in MICE
Event Display Place Holder
beam before solenoid arrival
14
2012 Plans
• Completion and mapping of spectrometer solenoids
• Installation of trackers into MICE hall
• LH2 system and focus coil completion
• Step 4 running end of 2012/beginning 2013
2013+ Plans
• Arrival and installation of two more absorber focus coil
modules
• RF cavities and coupling coils
• Step 5 and 6 Running
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