1. Downstream Cherenkov Gh. Grégoire University of Louvain MICE collaboration meeting RAL, October 28, 2004 Design study for the Technical Reference Document 1 Physical constraints Mechanics Evaluation of the optics Electronics

2. T.J. Robert’s simulations At CKOV2 entrance window At MUCAL entrance face 2

3. Optics 12 identical systems 3

4. Outer steel shielding Front panel (iron) Back panel (iron) Partially aluminized glass window O-ring Welds Transverse clamps for window Low carbon iron cylinder O-ring Cut along z-axis 4

5. Elementary module Hollow wedges (iron) to construct 12-sided polygon Part of front panel (20 mm iron) Part of back panel (20 mm iron) Longitudinal clamps for window BNC hole for light pulser Beam axis Centering rings and suspension rods for PM tube 5

6. Mumetal shielding Mumetal Fixation washers of the mumetal to the iron lid Beam axis 6 30° wedge pieces welded to front and back panels

7. Basic unit Beam axis 7 30° wedge pieces External magnetic shielding (5 mm soft iron)

8. Construction of 12-sided ring Single-piece front and back panels welded to the wedge pieces Hollow wedge pieces 8

9. Pyramidal mirror and exit window PARTICLE EXIT WINDOW: one single piece of 10-mm thick honeycomb with a 1- mm Aluminium skin on the inner face Downstream flat mirrors (4 pieces polycarbonate 3-mm thick; glued to honeycomb) 12-sided 45° pyramidal mirror (polycarbonate sheets supported by a honeycomb structure) 9

10. Aerogel box and entrance window Aerogel support box (honeycomb) Mirror upstream surfaces (4 pieces polycarbonate 3-mm thick on a 10-mm honeycomb ring; glued to aerogel box) Aerogel tiles (each 113 x 113 x 10 mm) to cover a diameter of ~ 800 mm; 100 mm thick) 10 PARTICLE ENTRANCE WINDOW: one single piece of 10-mm thick honeycomb with a 1-mm Aluminium skin on the inner face

11. Transverse cut 11 Cut through the support structure of the reflecting pyramid

12. Longitudinal cut 12

13. 3D view 13 Overall view without the aerogel and the particle entrance window

14. Optics Optical parts implemented into ZEMAX-EE Aerogel 14

15. Light collection efficiency 500 random light rays from the aerogel exiting through the photocathodes… 15

16. MC simulations Assume the muons generated by Tom are electrons … X vs Y Momentum Theta Phi 16

17. Ongoing work Assume the muons generated by Tom are electrons … Generation of photons inside the aerogel Propagate through optical sytem 17 Determine light collection efficiency ~ 60-70 % ( preliminary )

18. CKOV2 Electronics For each PM tube1 discriminator + fanout 1 QDC 1 TDC 1 light pulser + LED driver Fast electronics Slow controls1 Temperature sensor 1 Humidity sensor 1 Pressure sensor (helium) 12 HV control/monitoring channels (current/voltage) 12 times ! Data flow1 QDC and 1 TDC reading per good (muon) candidate Data flow1 reading of each per setting (run ?) For Edda 1 trigger for light pulser every n minutes (n?)