1. Claudia Höhne CBM collaboration meeting Dubna, October 20081 RICH workgroup program TimeNameTitle 9:00Claudia Höhne (GSI)Status report RICH R&D: - RICH MAPMT tests at GSI/ FEE - RICH design (PNPI) - mirror R&D (HSE) - RICH prototype (Pusan) 9:30Elena BelolaptikovaRICH layout simulations 9:50Vladimir Rykalin (IHEP)PMT and WLS activities at IHEP 10:10Piotr Koczon (GSI)WLS film studies 10:40alldiscussion 11:00COFFEE Wednesday, October 15, 2008:

2. Claudia Höhne CBM collaboration meeting Dubna, October 20082 Electron identification TimeNameTitle 11:00COFFEE 11:30Simeon Lebedev (GSI/JINR) Electron identification in RICH and TRD 12:00Tatiana Akishina (JINR)Energy loss studies of electrons in the TRD 12:15Olga Denisova (JINR) Systematic studies of e/  identification in TRD 12:30LUNCH

3. Claudia Höhne CBM collaboration meeting Dubna, October 20083 Status RICH R&D layout and designE. Vznuzdaev, O. Tarasenkova, E. Belolaptikova, S. Lebedev mirrorM. Dürr PhotodetectorS. Bianco, P. Koczon, CH WLS film studies FEE test setup at GSI activities at IHEP ProtvinoV. Rykalin prototypeI.-K. Yoo, J. Yi, et al.

4. Claudia Höhne CBM collaboration meeting Dubna, October 20084 RICH design Visit of Evgeny Vznuzdaev and Olga Tarasenkova (PNPI, St. Petersburg) at GSI, April 2008 discussion on RICH design so far dimensions are still subject of layout optimization only range can be given (compact to standard RICH dimensions) discussions on integration of RICH an MuCh in CBM Cave mirror layout and support discussed in some more detail current schedule: Preproduction design and prototyping: 2009 - 2010 Production : 2011 - 2015 Assembling and testing : 2014 - 2015

5. Claudia Höhne CBM collaboration meeting Dubna, October 20085 RICH mirror design "mirror and support are one thing" (!) important consideration: mirror tiles of hexagon or rectangular shape? mirror material: glass, carbon, beryllium ? mirror support structure – depends on shape of mirror tiles hexagon tiles: one mount in center of mirror adjustment around 2 axis rectangular tiles: typically 3 adjustable mounts also shift along z-axis possible or or...

6. Claudia Höhne CBM collaboration meeting Dubna, October 20086 Hexagonal mirror tiles Hexagon effects: Lack of exact geometrical description; impossible to divide a spherical surface into hexagons exactly ; one can only to approximate (manually?) the surface by hexagons with irregular gaps between them (0.5-12mm); Cutting of hexagons to fit a line between 2 mirrors and to fit (if necessary) other sides of the surface  different size of hexagons. E. Vznuzdaev, PNPI St. Petersburg

7. Claudia Höhne CBM collaboration meeting Dubna, October 20087 Rectangular mirror tiles Latitude/longitude division: The globe-wise division has a precise geometrical description; Minimal gaps between units, only technological gaps; Only 2 variants of unit dimensions; No fitting cuts for units E. Vznuzdaev, PNPI St. Petersburg

8. Claudia Höhne CBM collaboration meeting Dubna, October 20088 RICH mirror design considerations Detector Rc Division S/mirror S/unit Mirror Rad. [m] layout[m2] [m2]substrate thickness ---------------------------------------------------------------------------------------------------- Hermes 2.2 2x4 (T*) 1.6 0.8x0.25 CFC 0.01 LHCb(1) 2.7 1x4 (T*) 1.9 0.8x0.6 Be 0.007 CBM 3.0? 5.9 ? ? ? PHENIX4.0 2x12(T*) 10.0 0.8x0.5 CFC 0.004 ---------------------------------------------------------------------------------------------------- Compass6.6 58(H*) 10.5 0.18(0.5**) Glass 0.06 LHCb(2) 8.6 21(H*) 4.1 0.17(0.5**) Glass 0.05 * T – trapezoid, H – hexagon ** diameter of circumscribed circle E. Vznuzdaev, PNPI St. Petersburg

9. Claudia Höhne CBM collaboration meeting Dubna, October 20089 RICH mirror design considerations Common consideration (hexagonal shape): The geometrical relation between linear dimension of mirror unit d and radius of curvature Rc for Compass/LHCb2 case: K=d/RC=0.5/7.5 = 0.067 (soccer ball has K~0.75). Let us take the same K for CBM case. Then: d=(Rc)xK=3.0x0.067=0.2m, and number of hexagon units is 84 for square of 5.9m 2, what significantly increases amount of substance for mirror support (radiation thickness). Also we should increase correspondingly the number of tuning elements for mirror unit and time for their assembling and adjustment. All above brings to increasing of the cost for the mirror support also. E. Vznuzdaev, PNPI St. Petersburg

10. Claudia Höhne CBM collaboration meeting Dubna, October 200810 RICH mirror design considerations Detector Rc Division S/mirror S/unit Mirror Rad. [m] layout[m2] [m2]substrate thickness ---------------------------------------------------------------------------------------------------- Hermes 2.2 2x4 (T*) 1.6 0.8x0.25 CFC 0.01 LHCb(1) 2.7 1x4 (T*) 1.9 0.8x0.6 Be 0.007 CBM 3.0 84(H*) 5.9 0.07(0.2**) Glass 0.05 PHENIX4.0 2x12(T*) 10.0 0.8x0.5 CFC 0.004 ---------------------------------------------------------------------------------------------------- Compass6.6 58(H*) 10.5 0.18(0.5**) Glass 0.06 LHCb(2) 8.6 21(H*) 4.1 0.17(0.5**) Glass 0.05 * T – trapezoid, H – hexagon ** diameter of circumscribed circle E. Vznuzdaev, PNPI St. Petersburg

11. Claudia Höhne CBM collaboration meeting Dubna, October 200811 RICH mirror design considerations E. Vznuzdaev, PNPI St. Petersburg

12. Claudia Höhne CBM collaboration meeting Dubna, October 200812 RICH mirror design considerations Detector Rc Division S/mirror S/unit Mirror Rad. [m] layout[m2] [m2]substrate thickness --------------------------------------------------------------------------------------------------- - Hermes 2.2 2x4 (T*) 1.6 0.8x0.25 CFC 0.01 LHCb(1) 2.7 1x4 (T*) 1.9 0.8x0.6 Be 0.007 CBM 3.0 3x10(T*) 5.9 0.43x0.46 Glass 0.05 PHENIX4.0 2x12(T*) 10.0 0.8x0.5 CFC 0.004 --------------------------------------------------------------------------------------------------- - Compass6.6 58(H*) 10.5 0.18(0.5**) Glass 0.06 LHCb(2) 8.6 21(H*) 4.1 0.17(0.5**) Glass 0.05 * T – trapezoid, H – hexagon ** diameter of circumscribed circle E. Vznuzdaev, PNPI St. Petersburg

13. Claudia Höhne CBM collaboration meeting Dubna, October 200813 RICH mirror R&D February 2008: first mirror prototypes tested (FLABEG, 6mm thickness, 3.2m radius Al+MgF 2 reflective coating) good reflectivity (75% at 180nm) however: surface irregularities on cm scale nevertheless: one sample shipped to Pusan (Korea) for new RICH prototype discussions with FLABEG, but 2nd mirror sample of FLABEG had basically same deficciency contact to Compass company (Czech), waiting for new prototype (supplier of RICH2 mirrors of LHCb) M. Dürr, HS Esslingen

14. Claudia Höhne CBM collaboration meeting Dubna, October 200814 Mirror mount E. Vznuzdaev, PNPI St. Petersburg mirror mount for rectangular mirrors: to be tested as soon as possible together with new mirror prototypes test bench available at PNPI

15. Claudia Höhne CBM collaboration meeting Dubna, October 200815 Open Questions mirror material – glass, carbon beryllium??? material of mirror mount – aluminum, carbon structures,... ??? which material budget can we allow for while still having highly efficient global tracking capabilities? mirror radius? RICH layout, size? can we stay with direct reflection to photodetector plane and resulting high ring densities with smaller radius? sufficient surface regularity with small mirror radii? (what is sufficient?) simulations and work of E. Belolaptikova, S. Lebedev simulations to be done, test in RICH prototype (Selection of open questions:)

16. Claudia Höhne CBM collaboration meeting Dubna, October 200816 RICH layout studies RICH layout studies by Elena Belolaptikova (GSI summer student): systematic studies on RICH material budget (standard RICH), in particular concerning the RICH mirror and its effect on global tracking glass mirror of 3mm, 6mm, 10mm thickness aluminum support structure from aluminum rods included: radius 3 cm, 5mm wall thicknes radius 1.5 cm, 2 mm wall thickness (proposal of E. Vznuzdaev, industry standard) layout optimization of compact RICH detector Systematic investigation and improvement of ring finder in high ring density environment, Simeon Lebedev (GSI/JINR) ring finding and electron identification for standard & compact RICH scenario

17. Claudia Höhne CBM collaboration meeting Dubna, October 200817 Photodetector R&D (GSI) GSI activities on photodetector FEE, single photon test setup (Simone Bianco (summer student), Piotr Koczon, C.H.) wavelengthshifter (WLS) film studies in cooperation with CERN * development of FEE based on n-XYTER for MAPMT (Hamamatsu, H8500) development of test setup for single photon measurements at GSI pulse height distributions of single photons crosstalk effects with and w/o WLS films * cooperation and help by A. Braem, M. van Stenis, C. Joram

18. Claudia Höhne CBM collaboration meeting Dubna, October 200818 Quarz  testbeam: protons, p=3.5 GeV/c  H8500 Hamamatsu H8500   sin  = n sin(  -  ) → for  = 20° is  = 37.7° for Quartz thickness of 1cm and R=5cm: L = 3.16 cm,  R = 1.15 cm RR R L ~6 cm tilting needed because otherwise light would be internally reflected in quartz to check: when does intenal reflection set in again Photodetector test during CBM testbeam Sep'08 ? plan was: participate with photodetector test, use Cherenkov light generated by protons (p = 3.5 GeV/c (2.3 GeV/c)) in plexiglas:

19. Claudia Höhne CBM collaboration meeting Dubna, October 200819 Simulations - testsetup setup in CbmRoot simulations: best tilting angle of plexiglas 45° appr. 50 photons/ event (plexiglass of 8 mm thickness) appr. MAPMT image S. Bianco, CH, GSI

20. Claudia Höhne CBM collaboration meeting Dubna, October 200820 n-XYTER readout for H8500 use n-XYTER chip for readout of H8500 problem: typical gain of H8500 1-2∙10 6 but dynamical range of n-XYTER 120000 e- need attenuator of appr. factor 20-50 → prepare PCB board n-XYTER FEB designed as general pupose board attenuator PCB board S. Bianco, CH, GSI

21. Claudia Höhne CBM collaboration meeting Dubna, October 200821 CBMRICHAB01 PMTN-XYTER R1R2C1C2 0  10 k  1 nF10 pF 91  10  0 nF2 pF 0  100  1 nF10 pF 91  10  0 nF10 pF 0  100  500 pF10 pF 0  0 F PCB board produced, several R-C combinations tested with test pulse ongoing discussions with detector lab S. Bianco, CH, GSI

22. Claudia Höhne CBM collaboration meeting Dubna, October 200822 Test of CBMRICHAB01 input (pulse generator): 2 V, 10 ns R 2 = 100 , C 1 = 1 nF, C 2 = 10 pF R 1 = 91 , R 2 = 10 , C 1 = 0 nF, C 2 = 10 pF 0.04 V 15 ns test with n-XYTER S. Bianco, P. Koczon, GSI

23. Claudia Höhne CBM collaboration meeting Dubna, October 200823.... n-XYTER FEB missing test setup was ready for the beam, however an n-XYTER FEB was missing (only 3 became available – 2 for the silicon strips, 1 for the GEM) S. Bianco, CH, GSI

24. Claudia Höhne CBM collaboration meeting Dubna, October 200824 Next steps more n-XYTER FEBs will become available in the near future, one existing (Rev B) can be shared already now with the silicon strip R&D group (J. Heuser) develop and understand n-XYTER readout of H8500 consider separate future version of CBM-XYTER specifically for H8500 investigate characteristics of H8500 single photon response, homogenuity across the surface and single pixels crosstalk effects w and w/o WLS coverage use MAPMT test setup for next CBM testbeam in February/ March 2009 provide readout to group of i.K. Yoo, Pusan University, Korea

25. Claudia Höhne CBM collaboration meeting Dubna, October 200825 RICH prototype development of RICH prototype at Pusan University, Korea (I.K. Yoo JunGyu Ji, et al.) first small scale prototype already investigated 2nd full scale prototype to be build autumn/ winter 2008 test various radiator gases/ mixtures combine parts developed elsewhere: implement first mirror prototype (FLABEG, 20 cm x 20 cm) once available: use n-XYTER for readout test: electron beam at TEST LINAC, PAL (Pohang Accelerator Lab.), Korea. ; (p e ≈ 60MeV/c) problem: very wide beam spot, poor beam quality → implement beam diagnostics, collimators!

26. Claudia Höhne CBM collaboration meeting Dubna, October 200826 RICH prototype mount for 4 H8500 MAPMTs extension vessel vessel_front window mirror: R = 2700 or 3200 mm side door J. Yi, I.K. Yoo, Pusan University, Korea

27. Claudia Höhne CBM collaboration meeting Dubna, October 200827 Photodetector "plane" in prototype J. Yi, I.K. Yoo, Pusan University, Korea ring on 4 MAPMTs

28. Claudia Höhne CBM collaboration meeting Dubna, October 200828 Mount for 4 MAPMTs Mount_0 4PMTs Mount_1 Bolt J. Yi, I.K. Yoo, Pusan University, Korea

29. Claudia Höhne CBM collaboration meeting Dubna, October 200829 Gas system Molecular Sieve T : 25C P :±20mbar H : ~ 23%RH  3196 ppm P : 3 atm P : ~1 atm J. Yi, I.K. Yoo, Pusan University, Korea

30. Claudia Höhne CBM collaboration meeting Dubna, October 200830 Summary: RICH prototype gas vessel under production in Pusan develop beam setup which allows to work with the existing poor beam quality n-XYTER readout to be investigated/ developed at GSI 1st mirror prototype delivered by HSE future prototypes will be combined and tested with mirror mount

31. Claudia Höhne CBM collaboration meeting Dubna, October 200831 Discussion layout and design studies mechanical concepts developed at PNPI, details on RICH size and mirror layout missing for further progress detailed (promising!) simulations on RICH material budget (mirror and mount), RICH layout, e-ID in high ring density environment mirror R&D 1st prototype shipped to Pusan for RICH prototype new prototypes expected soon, if promising combine with mount photodetector R&D promising WLS film studies (crosstalk with MAPMT?) FEE under way (plan use of n-XYTER FEB) test setup at GSI under development prototype under construction at Pusan university important: get beam quality under control!