1. CBM-RICH: Photodetector developement CBM Collaboration Meeting February 2008 P.Koczoń, C.Höhne, A.Braem C.Joram, S.Ilie, M. van Stenis CBM Workshop February 2008 Piotr Koczoń,GSI

2. CBM Workshop February 2008 Piotr Koczoń,GSI

3. CBM Workshop February 2008 Piotr Koczoń,GSI Photodetector for RICH CsI – MPWC, PM Array photomultiplier: H8500, H9500 geometrical properties -> coverage optical properties -> quantum efficiency electronical properties -> readout, cross-talk H8500: room for improvements: - WLS coating: technology, measurements, results - Single Photon Counting: measurement, results Outlook/Plans

4. CBM Workshop February 2008 Piotr Koczoń,GSI H8500 8x8 pads 5.8 x 5.8 mm each 89% packing density U=1100 V but borosilicate window and low QE for UV

5. CBM Workshop February 2008 Piotr Koczoń,GSI Wave-length shifter p-Terphenyl pTer Tetraphenyl Butadiene TPB

6. CBM Workshop February 2008 Piotr Koczoń,GSI Coating plant (theory) Schutter Boat PMs Heating Vacuum Quartz crystal microbalance Material

7. CBM Workshop February 2008 Piotr Koczoń,GSI Coating plant (reality)

8. CBM Workshop February 2008 Piotr Koczoń,GSI Depositing pTer, TPB and YellowX TPBpTerYellowX PM5 41 μg/cm 2 63 μg/cm 2 PM4 65 μg/cm 2 95 μg/cm 2 276 μg/cm 2 PM3 92 μg/cm 2 PM2162 μg/cm 2 PM1235 μg/cm 2 343 μg/cm 2

9. CBM Workshop February 2008 Piotr Koczoń,GSI QE Test Bench (HPD) - Air - 200 nm cut off - abs. QE measurement Monochromator -Vacuum - deep UV - no absolute QE Quantum efficiency measurements (theory)

10. CBM Workshop February 2008 Piotr Koczoń,GSI Monochromator QE Test Bench Quantum efficiency measurements (reality)

11. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 PRELIMINARY

12. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 coated with TPB PRELIMINARY

13. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 coated with pTer PRELIMINARY

14. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 with YellowX PRELIMINARY

15. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 @ far UV I A (λ) = F(λ) * QE(λ) R(λ) = I A wls (λ)/ I A (λ) = QE wls (λ) / QE(λ) QE wls (λ) = R(λ) * QE(λ) = I A wls (λ)/ I A (λ) * QE(λ)

16. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 @ far UV for p-Ter for TPB I A wls (λ)/ I A (λ) PRELIMINARY

17. CBM Workshop February 2008 Piotr Koczoń,GSI QE for XP3102 @ far UV for TPB for p-Ter PRELIMINARY

18. CBM Workshop February 2008 Piotr Koczoń,GSI Single photon counting capability ( theory) PM HV PulseGenerator Pico FADC n grey filters Light guide bundle Light tight box LED gate signal

19. CBM Workshop February 2008 Piotr Koczoń,GSI Single photon counting capability ( reality) n times grey filter Light guide bundle Dark box LED signal Pulse generator (a bad one) HV

20. CBM Workshop February 2008 Piotr Koczoń,GSI Single photon counting capability - results

21. CBM Workshop February 2008 Piotr Koczoń,GSI Single photon counting capability - results Not convincing!!! A combined pulse-amplitude - time-series analysis necessary.

22. CBM Workshop February 2008 Piotr Koczoń,GSI Open questions: WLS - ageing in CO 2 – next measurement at CERN in June 2008 - mechanical properties Single Photon Counting - final proof for H8500 Cross-talk between neighbouring pixels (with and w/o WLS) Readout - nXyter – April 2008 - nXyter: adapter – charge divider RICH-prototype for the test run in Fall´08

23. CBM Workshop February 2008 Piotr Koczoń,GSI Thank You !

24. CBM Workshop February 2008 Piotr Koczoń,GSI