1. ISIS Related Issues for MICE Adam Dobbs Proton Accelerator Development Meeting, RAL 24 th March 2011 24/03/20111A. 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 24/03/2011A. Dobbs2

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 24/03/20113A. 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 2.2 μ s to fast to permit traditional cooling techniques → ionisation cooling 24/03/2011A. Dobbs4

5. 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 24/03/2011A. Dobbs5 LiH 2 v v RF v

6. MICE Step VI 24/03/2011A. Dobbs6

7. MICE in ISIS and the Beamline 24/03/2011A. Dobbs7

8. 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. 24/03/2011A. Dobbs8

9. ISIS Beam loss 24/03/2011A. Dobbs9 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

10. Beam Loss and Target Depth 24/03/2011A. Dobbs10

11. Beam Loss and MICE Particle Rate Linear correlation Constant offset Averaged data – few hundred pulses per point Pion optics 24/03/2011A. Dobbs11

12. Beam Loss and MICE Particle Rate 24/03/2011A. Dobbs12 -ve π → μ optics+ve π → μ optics Still linear Spill-by-spill data (no averaging)

13. Beam Loss and MICE Particle Rate Not linear at low beam loss... not to worry, believed to be caused by a mis-configured gate 24/03/2011A. Dobbs13 +ve π → μ optics, “10V study”

14. ...but what about Muons? 24/03/2011A. Dobbs14 Use Time-of- Flight to perform Particle Identification -ve π → μ optics

15. Beam Loss and Muon Rate 24/03/2011A. Dobbs15 -ve π → μ optics+ve π → μ optics Still linear

16. Muon Rate Numbers 24/03/2011A. Dobbs16 So, depending on MICE optics get a few 10’s of muons per 1ms spill

17. Conclusion 24/03/2011A. Dobbs17 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

18. Appendix I: Run conditions 24/03/2011A. Dobbs18