Download ISIS Related Issues for MICE

ISIS Related Issues
for MICE
Adam Dobbs
Proton Accelerator Development Meeting, RAL
24th March 2011
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Contents
• Introduction to MICE
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Purpose
Ionisation Cooling
The Cooling Channel
MICE in ISIS and the Beamline
• ISIS beam loss measurement
• ISIS beam loss and MICE particle rate
– Beam loss and target depth
– Beam loss and particle rate
– Beam loss and muon rate
• Conclusion
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Muon Ionisation Cooling
Experiment
• Purpose: investigate the feasibility of
ionisation cooling, for application to a future
Neutrino Factory or Muon Collider.
• Neutrino Factory → Precision measurements
of neutrino oscillations
• Muon Collider → Multi-TeV lepton –
anti-lepton collisions
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Ionisation Cooling - Why
• An NF muon beam requires cooling (emittance
reduction) in order to fit efficiently within the
acceptance of downstream acceleration
components
• An MC also requires small interaction points
to increase luminosity
• Muon lifetime of 2.2μs to fast to permit
traditional cooling techniques → ionisation
cooling
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Ionisation Cooling - How
• Pass the beam through an absorber e.g. liquid
hydrogen, lithium hydride
• The particle beam ionises the medium, the beam
particles losing energy and momentum in all
directions
• Re-accelerate the beam in the beamline direction
(z) only, using a radio frequency electric field
v
LiH2
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RF
v
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MICE Step VI
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MICE in ISIS and the
Beamline
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The MICE target
• A 24 coil stator is used to
drive a shuttle, consisting
of a titanium shaft upon
which are mounted
permanent magnets to
couple to the field
produced by the stator
• The lower end of the shaft
takes the form of a hollow
cylinder, which is pulsed
into the ISIS beam by the
stator
• Upper and lower bearings
are used to maintain the
transverse position of the
shaft.
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ISIS Beam loss
• 39 argon gas
ionisation chambers
around the ring
• Use the summed
signal of the four
sector 7 BLMs,
integrate over the
whole 10ms ISIS
cycle (V.ms)
• Slightly different
gauge used than
ISIS (smaller by ∼
1/3 )
Increased beam loss levels raise the concerns over machine
activation levels inhibiting hands-on maintenance
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Beam Loss and Target Depth
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Beam Loss and
MICE Particle Rate
• Linear
correlation
• Constant
offset
• Averaged
data – few
hundred
pulses per
point
• Pion optics
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Beam Loss and
MICE Particle Rate
Spill-by-spill data (no averaging)
-ve π → μ optics
+ve π → μ optics
Still linear
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Beam Loss and
MICE Particle Rate
+ve π → μ optics, “10V study”
Not linear at low beam loss... not to worry,
believed to be caused by a mis-configured gate
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...but what about Muons?
• Use Time-ofFlight to perform
Particle
Identification
• -ve π → μ optics
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Beam Loss and Muon Rate
-ve π → μ optics
+ve π → μ optics
Still linear
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Muon Rate Numbers
So, depending on MICE optics get a few 10’s of muons per 1ms spill
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Conclusion
• The MICE Muon Beamline is functioning well in ISIS,
and has been for sometime
• Depending on MICE optics, the beamline delivers a
few 10’s of muons per 1ms spill that can be used
• Desired rate is several hundred “good” muons per 1ms
spill
• Would probably require beam loss levels that are
intolerable to ISIS
• Various solutions put forward:
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Increased MICE target dip rate
Longer MICE data running to account for lower rates
ISIS beam bump at MICE target
Improved ISIS collimator system
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Appendix I: Run conditions
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