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ISIS Related Issues for MICE. Adam Dobbs Proton Accelerator Development Meeting, RAL 24 th March 2011. Contents. Introduction to MICE Purpose Ionisation Cooling The Cooling Channel MICE in ISIS and the Beamline ISIS beam loss measurement ISIS beam loss and MICE particle rate - PowerPoint PPT Presentation
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A. Dobbs 1
ISIS Related Issues for MICE
Adam DobbsProton Accelerator Development Meeting, RAL
24th March 2011
24/03/2011
A. Dobbs 2
Contents
• Introduction to MICE– 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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A. Dobbs 3
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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A. Dobbs 4
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
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LiH2
v
v 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
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• 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
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-ve π → μ optics +ve π → μ opticsStill linear
Spill-by-spill data (no averaging)
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Beam Loss and MICE Particle Rate
Not linear at low beam loss... not to worry,believed to be caused by a mis-configured gate24/03/2011
+ve π → μ optics, “10V study”
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...but what about Muons?
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• Use Time-of-Flight to perform Particle Identification
• -ve π → μ optics
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Beam Loss and Muon Rate
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-ve π → μ optics +ve π → μ optics
Still linear
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Muon Rate Numbers
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So, depending on MICE optics get a few 10’s of muons per 1ms spill
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Conclusion
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• 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:
– 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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