Radius of diffuser and sizes for PID

1. Radius of diffuser and sizes for PID M. Apollonio – University of Oxford MICE Analysis meeting 23/1/2007

2. Let’s consider different optics for MICE Consider the maximum radius a particle can reach in the tracker (TK) = 15 cm the absorber (ABS) = 15 cm the RF windows (RF) = 21.3 cm It can be shown that b ~ <R2> Propagate the radius throughout MICE according to These curves represent the ENVELOPE of the beam which just touches the TK, the ABS, the RF and the diffuser == muons with a given amplitude == MAX size of diffuser MAX radii in the downstream region CAVEAT: field in the downstream region is approximate, neglecting the presence of the shield!!! MICE Analysis meeting 23/1/2007

3. current diffuser position ideal minimum RD MICE Analysis meeting 23/1/2007

4. Wang-200-42 Z-downstream: shield-in shield-out SW TOF KL MICE Analysis meeting 23/1/2007

5. inside TKs • inside ABS • inside RF current diffuser position ideal minumum RD Every m in the TKs will traverse both ABS and RF RD must be as large as possible 10 cm is definitely too small !!! MICE Analysis meeting 23/1/2007

6. Wang 207-200-193 (with energy loss) R grows linearly far from the solenoid (beta ~ z2) MICE Analysis meeting 23/1/2007

7. Wang-240-42 MICE Analysis meeting 23/1/2007

8. Wang-240-42 MICE Analysis meeting 23/1/2007

9. NF-200-42 MICE Analysis meeting 23/1/2007

10. NF-200-42 MICE Analysis meeting 23/1/2007

11. SFOFO-170-15 MICE Analysis meeting 23/1/2007

12. SFOFO-170-15 MICE Analysis meeting 23/1/2007

13. SFOFO-140-7 MICE Analysis meeting 23/1/2007

14. SFOFO-140-7 MICE Analysis meeting 23/1/2007

15. Summary of min R – DIFFUSER (cm) MICE Analysis meeting 23/1/2007

16. Definition of MIN Radius for PIDs and SHIELD holes !!! NOT IN SCALE (but figures should be correct) 250 100 100 50 250 40 800 40 700 KL SW max radius 50 TOF 6399.5 6499.5 6574.5 6649.5 6729.5 7429.5 6524.5 6599.5 6689.5 MICE Analysis meeting 23/1/2007

17. According to the defs given in previous slides these are the min radii (a) for the shield (to let every m pass) and (b) for the PIDs (to accept every m) Slightly out ? tolerances Within tolerances 600x600 700x700 mm2 1000x1000 mm2 Is it a problem? MICE Analysis meeting 23/1/2007

18. Wang-200-42 like having a 20 cm shorter SW calorimeter But only for the outer muons Z-downstream: shield-in shield-out SW TOF KL MICE Analysis meeting 23/1/2007

19. conclusions the maximum radii for particles traversing MICE are propagated (from the max R in 3 different places) through the apparatus (TKs, ABS, RF) Considering several optics: min Radius (at fixed position z=-6150 mm) for the diffuser is defined: in order to have particles in the TKs it turn out Rd should be as large as possible (compatible with mechanical contraints) In any case RD=10 cm is too small ! min radii for downstream shield holes are computed upon the requirement of accepting every m from trackers min radii for PIDs are computed upon the requirement of having the maximal acceptance within the detector: this condition can be probably relaxed Real B field in the “shield area” should take into account real map. This is just an approximation whose purpose is giving some initial figures MICE Analysis meeting 23/1/2007