Ckov1, Ckov2, Tof2 MICE Pid Tele-Meeting

1. Ckov1, Ckov2, Tof2 MICE Pid Tele-Meeting Steve Kahn 31 March 2005 Steve Kahn -- Ckov and Tof Detector Simulation

2. Improvements to G4Mice Relevant to the Cherenkov Detectors • Ckov1: • Implement the new Mississippi geometry. • Corrections to better handle the threshold effect for PE generation. • Ckov2: • Better model the materials used in Ckov2. • Previous version had too much material in the beam windows. • We now take into account the reduced material due to the honeycomb geometry. • Updated Ckov2 dimensions. Steve Kahn -- Ckov and Tof Detector Simulation

3. Steve Kahn -- Ckov and Tof Detector Simulation

4. Event Samples for Ckov1 Study • Samples with 50%  and 50%  are generated. • Events are generated just before Tof0 (-15750 mm) with • x=y=50 mm • x’=y’=25 mr • Samples were run with the following momenta. • 180, 200, 220, 240, 260 MeV/c. • Current G4Mice problem generates contamination with constant KE, where it should be constant momentum since they survive the final dipole bend. Consequently muon and pion samples must be run separately. Steve Kahn -- Ckov and Tof Detector Simulation

5. Cherenkov Systems • Upstream Ckov • C6F14 radiator with n=1.25 • 4 PMTs • 2 on top, 2 on bottom. • Threshold cherenkov: • 0.7 MeV for electrons • 140 MeV for muons • 190 MeV for pions • Downstream Ckov • Aerogel with n=1.03 • 12 PMTs on 12-sided polygon. • Typically on electrons visible since pion threshold is > 500 MeV. • Requires TOF coincidence. Steve Kahn -- Ckov and Tof Detector Simulation

6. Cherenkov Threshold Effect • The number of Č photons generated by the passage of a charged particle through the radiator is Steve Kahn -- Ckov and Tof Detector Simulation

7. Ckov1 PEs generated: 181 MeV/c • No Pion plot since pions are below threshold for 181 MeV/c • Units on the abscissa are arbitrary at this point. • They are valid for comparison from plot to plot. • I believe that they are high by a factor of 5. Steve Kahn -- Ckov and Tof Detector Simulation

8. Ckov1 PE’s generated: 200 MeV/c • Although 200 MeV/c are above threshold none were generated in the run. Steve Kahn -- Ckov and Tof Detector Simulation

9. Ckov1 PE’s generated: 220 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

10. Ckov1 PE’s generated: 240 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

11. Ckov1 PE’s generated: 260 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

12. Photon Generation in the Cherenkov Detectors • For each track that crosses the radiator with a velocity above threshold a number of photons are generated proportional to the deposited energy. • We currently do not use the Cherenkov photon facility in Geant4. • There is some question as to how well it works with reflective surfaces. • Imaginary photons are generated in a cone (at the č angle) around the particle direction. • Since all mirrors are at 45º w.r.t. the beam direction, we can position the PMTs on an imaginary plane. • The č photons that intercept the PMT circles are “seen”. • Note that Ckov1 has an angle of 53°. The circles should be ellipses. This has not yet been taken into account • Note that in Ckov 1 we are dealing with only 4 PMTS. Steve Kahn -- Ckov and Tof Detector Simulation

13. Ckov1 PE’s seen: 181 MeV/c • No seen pions since they are below threshold. Steve Kahn -- Ckov and Tof Detector Simulation

14. Ckov1 PE’s seen 200 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

15. Ckov1 PE’s Seen 220 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

16. Ckov1 PE’s seen: 240 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

17. Ckov1 PE’s seen: 260 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

18. Ckov1 Efficiency as a Function of Energy P=180 MeV/c P=240 MeV/c Steve Kahn -- Ckov and Tof Detector Simulation

19. Data Sample for Downstream Detectors • Generated samples of muons and electrons. • 20 K events of each kind • Tracks started at –4802 mm. Near the beginning of the upstream SciFi. • Muons have KE 120 MeV. E225 MeV. • Electrons have KE centered at 70 MeV and have E/E=35%. Steve Kahn -- Ckov and Tof Detector Simulation

20. Tof2 Muon Position Scatter Plot Steve Kahn -- Ckov and Tof Detector Simulation

21. Tof2 Muon Position Projections Steve Kahn -- Ckov and Tof Detector Simulation

22. Tof2 Muon Radial Distribution Steve Kahn -- Ckov and Tof Detector Simulation

23. Tof2 Electron Position Scatter Plot Steve Kahn -- Ckov and Tof Detector Simulation

24. Tof2 Electron Position Projections Steve Kahn -- Ckov and Tof Detector Simulation

25. Tof2 Electron Radial Distribution Steve Kahn -- Ckov and Tof Detector Simulation

26. Ckov2 Muon Position Scatter Plot Steve Kahn -- Ckov and Tof Detector Simulation

27. Ckov2 Muon Position Projections Steve Kahn -- Ckov and Tof Detector Simulation

28. Ckov2 Muon Radial Distribution Steve Kahn -- Ckov and Tof Detector Simulation

29. Ckov2 Electron Position Scatter Plot Steve Kahn -- Ckov and Tof Detector Simulation

30. Ckov2 Electron Position Projections Steve Kahn -- Ckov and Tof Detector Simulation

31. Ckov2 Electron Radial Distribution Steve Kahn -- Ckov and Tof Detector Simulation

32. Ckov2 Efficiency Steve Kahn -- Ckov and Tof Detector Simulation