1. 1. Optical matching in MICE Ulisse Bravar University of Oxford 2 June 2004 Constraints Software MICE proposal mismatch MICE Note 49 (September 2004, Bob Palmer) New Coils from Mike Green MICE Stages IV and V Current issues

2. 2. Constraints Baseline configuration: flip mode p = 200 MeV/c   = 42 cm in LH Goals: achieve minimum   as stated: FC & CC uniform B-field inside spectrometer (to 1%): EC uniform   inside spectrometer: MC

3. 3. Software Matching code from Bob Palmer: ICOOL + minimization routine ‘empty’ MICE channel paraxial tracks Numerical evolution of  , by John Cobb: ‘empty’ MICE channel   from G. Penn, MuCool note 71: 2     ’’ – (   ’) 2 + 4   2  2 – 4 = 0

4. 4. MICE proposal MICE proposal to RAL: coil configuration from tab. 4.1 currents from tab. 4.2, case 1a p = 220 MeV/c p = 200 MeV/c p = 180 MeV/c MISMATCH for p = 200 MeV/c !!!

5. 5. MICE Note 49 Currents from Bob Palmer’s note, Sept. 2003 Tab. 4 & 5 SFOFO   = 43 cm 200 MeV/c   looks OK:   = minimum in LH   = uniform in solenoid Mismatches at 180 and 220 MeV/c

6. 6. New Coils Coil configuration from Mike Green and INFN-GE after CERN 2004 meeting (room temperature). Currents determined with Bob Palmer’s minimization routine. Again   at p = 200 MeV/c looks OK. Note: big   increase in match coil region.

7. 7. MICE stages IV and V

8. 8. Present issues Visibly, BP ‘better’ than MG. How good is good? Issues: achromaticity beam scraping, large   in MC, stay-clear area peak B-field in FC varies, i.e. B = 0 away from centre of LH

9. 9. ICOOL simulations (1) Actual beam ‘Empty’ channel   from paraxial beam consistent with   from G. Penn eqn.   from beam with   = 6  mm rad is mismatched

10. 10. ICOOL simulations (2) ‘Empty’ channel + paraxial beam ‘Empty’ channel + actual beam ‘Full’ channel (i.e. LH + RF) + actual beam (i.e.   = 6  mm rad) Problem: matching for p = 200 MeV/c, but p is NOT constant along ‘full’ channel.

11. 11. Cooling MICE proposal MICE Note 49 New coils   = 6  mm rad, cooling  = 13.5% (MICE proposal) 15.2% (MICE Note 49) 14.6% (New coils)

12. 12. Conclusions We have a realistic set of coils and currents with an appropriate optic solution Solution is OK for Stages V & VI (and IV) Need to determine optic solutions for all MICE momenta, various   -values and flip, no-flip & semi-flip modes A lot of fine-tuning is necessary to achieve optimum performance

13. 13. Appendix Present coil configuration, MICE Stage VI. Coils and currents from CERN 2004 meeting. Flip mode, p = 200 MeV/c,   = 42 cm in LH.