RICH simulation for CLAS12 Hall B Central Detector Forward Detector Contalbrigo Marco INFN Ferrara Luciano Pappalardo M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 1

Mean pk separation (4.5-5 GeV) Pad size 2 cm Pad size 0 cm VISIBLE light Pad size 2 cm UV+VIS light UV light The hybrid photon detector option M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 2

Status and outlook Hybrid (visible + UV photons) solution C6F14 + visible light should satisfy ID requirements with small pad size High cost for photon detection High material budget affecting TOF Hybrid (visible + UV photons) solution - will probabily require reduced UV fraction - affects anyway TOF C5F12 (UV photons) solution - will probabily resemble C6F14 + UV light - technologically challenging C6F14 (selected UV photons) solution - reduced chromatic error - balance with reduced number of photons Effect of PMT plane on TOF with Geant 3? M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 3

Status and outlook C6F14 + visible light should satisfy ID requirements with small pad size High cost for photon detection High material budget affecting TOF Cerenkov TOF a-la PANDA - faster than scintillator light - single photon collection allows for refined photon-path corrections in principle sensitive to the Cerenkov angle Mirror solution (photon detector outside particles trajectories) - reflecting upward toward larger radius - reflecting on a side toward toroid shadows Toward real experimental conditions p,p,k with their specific spectra Real particle multiplicity M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 4

Time-of-flight disc RICH It measures Cherenkov light that is generated and internally reflected in a 2 cm thick fused silica plate. The Cherenkov angle is reconstructed from a time-of-propagation measurement at the rim of the disc of individual Cherenkov photons with a resolution of better than 50 ps. Dichroic mirrors at the rim of the disc fulfil two purposes. They allow for a selection of certain wavelength bands and thus are used to reduce dispersive smearing, and they enlarge the average photon path length by reflection and thus improve the separation power of the detector. M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 5

Time-of-flight disc RICH Possible hadron ID at large photon paths (and limited momentum) Why not to use it as a TOF ? Photon detector on the side of the sector (< 1 m2) M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 6

Time-of-flight disc RICH Vertical quartz slab, 3 cm thick Photon detector all around slab edge M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 7

Time-of-flight disc RICH P=1.9 GeV/c Quartz light attenuation length = 500 cm Number of detected photons ~ 150 M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 8

Time-of-flight disc RICH P=4.2 GeV/c Reduced photon detection area ( < 1 m2 per sector) Minimized effect on standard TOF Compatible with a standard (UV?) RICH M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 9

Time-of-flight disc RICH Vertical quartz slab, 3 cm thick Photon detector all around slab edge M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 10

RICH detector ratio K/ ~ 0.1-0.15 p/K p/p K/p 3 cm 80 cm Substitute 2 LTCC sectors with a proximity RICH detector 3 cm 80 cm GeV/c 1 2 3 4 5 6 7 8 9 10 p/K TOF LTCC HTCC p/p K/p ratio K/ ~ 0.1-0.15 M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 11

Simulation with realistic phase space To detemine the best photon detector size, ,K,p have been generated at the LTCC-RICH entrance window according with a realistic phase space distribution of reconstructed momenta and angles. (GeV/c) M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 12

Refraction index: freon Simulation based on most conservative n (Moyssdes) M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 13

Refraction index: quartz Quartz absorption length and refraction index from Khashan and Nassif, Optic communications 188 (2001) 129 M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 14

Geometry : 1 Assume: Two radiators (only 1 simulated); one per sector Not to scale Unit: mm and degree Assume: Two radiators (only 1 simulated); one per sector Detector covers up to 2 sectors (detect photons from both radiators) Radiator Polar acceptance: 5° ÷30°  fix radiator size ~ 4 m2 Max gap length = 120 cm M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 15

Geometry : 2 Space for support and neoceram ? Quartz (0.5cm) Space for support and neoceram ? Minimum radius fixed by 5o requirement ? How to define maximum radius ? B’ freon K Study gap depth and freon thickness 20° B C’ gap 90° C 538.5 +10 35° A’ 25° A O 5° beam line H H’ M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 16

Photon detector Hamamatsu R7400-U03: 18 mm diam., 12 mm length 0.8 x 0.8 cm2 pixel, 50 % packing density Spectral range 185-650 nm, max q.e. at 420 nm ~0.1 keu each: 1 m2 costs about 250 keuro Hamamatsu H8500/H9500: 52 mm square. 0.6 x 0.6 cm2 pixel, 89 % packing density Spectral range 300-650 nm, 25 % q.e. at 420 nm ~1.5 keu each: 1 m2 costs > 500 keuro Hamamatsu R7600-03-M16: 26 mm square. 0.5 x 0.5 cm2 pixel, 50 % packing density Spectral range 300-650 nm, max q.e. at 420 nm ~0.5 keu each: 1 m2 costs about 700 keuro M. Contalbrigo JLAB12 coll. Meeting 18 Nov 09 17