The HERMES RICH as SBS hadron identification detector SBS Meeting JLab : 19/March/2010 JLab 19/Mar/2010 III SBS Meeting The HERMES RICH as SBS hadron identification detector DeLeo, Cisbani / HERMES RICH Evaristo Cisbani / INFN-Rome Sanità Group Raffaele De Leo / University of Bari and INFN Bari

DeLeo, Cisbani / HERMES RICH Overview of the HERMES RICH HERMES RICH performances HERMES RICH in SBS JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH

HERMES Experimental Setup JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH 2 RICH identical modules

Hadron PID: HERMES RICH 5.5 GeV K+ C4F10 gas JLab 19/Mar/2010 III SBS Meeting REAL DATA from NIMA 479 (2002) 511 14.6 GeV e- 1.5 GeV p- DeLeo, Cisbani / HERMES RICH Two radiators: aerogel and gas PMTs as photon detector Focusing Optics Reference: NIMA 479 (2002) 511-530

HERMES RICH module layout 147 JLab 19/Mar/2010 III SBS Meeting 63 101 180 48 DeLeo, Cisbani / HERMES RICH 126 281 unit is cm

DeLeo, Cisbani / HERMES RICH Radiators JLab 19/Mar/2010 III SBS Meeting Dirk Rickbosch – DESY07 DeLeo, Cisbani / HERMES RICH Refractive Index n(633 nm)=1.03 + C4F10 Gas, n(633 nm)=1.00137

DeLeo, Cisbani / HERMES RICH Optics JLab 19/Mar/2010 III SBS Meeting Dirk Rickbosch – DESY07 DeLeo, Cisbani / HERMES RICH

DeLeo, Cisbani / HERMES RICH Photon Detector plane JLab 19/Mar/2010 III SBS Meeting Dirk Rickbosch – DESY07 DeLeo, Cisbani / HERMES RICH ¾ inch diameter

DeLeo, Cisbani / HERMES RICH Light Collection Dirk Rickbosch – DESY07 JLab 19/Mar/2010 III SBS Meeting ~20% of the HERMES RICH PMT array DeLeo, Cisbani / HERMES RICH

DeLeo, Cisbani / HERMES RICH Electronics Dirk Rickbosch – DESY07 JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH VME based, 20 MHz bus from front-end to VME less than 30 ms to transfer data to VME able to keep data up to 800 ns (selectable) since trigger down to 50 ns gate width No time information

One RICH Module during installation JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH

HERMES RICH performances DeLeo, Cisbani / HERMES RICH JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH

exp.- calc. angle resolution (%) HERMES c for single pe pe > 5 GeV Pixel 2.3 Mirror 0.6 Point emiss. 0.7 n disp. 0.5 Chromatic 1.3 Forw.Scatt. 0.4 Surface 0.4 Total (calc.)/pe 2.9 Total (exp.)/pe 3.3 Npe (exp.) 10 JLab 19/Mar/2010 III SBS Meeting Npe = 10 /=3.3%/pe DeLeo, Cisbani / HERMES RICH / = 1.1% /ring Largest error from pixel size (by design!)

DeLeo, Cisbani / HERMES RICH qC ring  n (e+>5GeV) plot vs day JLab 19/Mar/2010 III SBS Meeting n DeLeo, Cisbani / HERMES RICH

Dn ≈ 3 *10-4 in 10 years! Dn ≈ 1*10-4 in the last 5 years! average n (e+>5GeV) JLab 19/Mar/2010 III SBS Meeting Dn ~ 0.0003 Dn ~ 0.0003 DeLeo, Cisbani / HERMES RICH Dn ≈ 3 *10-4 in 10 years! Dn ≈ 1*10-4 in the last 5 years!

pe reconst.starting point distribution DeLeo, Cisbani / HERMES RICH e > 5 GeV JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH a real stable RICH ! DNpe < 0.2 0.3% in 10 years!

DeLeo, Cisbani / HERMES RICH HERMES RICH in SBS JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH

one RICH module now @ UVa (thanks to Gordon) JLab 19/Mar/2010 III SBS Meeting RICH DeLeo, Cisbani / HERMES RICH Aerogel Spare Now stored at UVa under safe/controlled conditions + additional wall of spare Aerogel from the other module.

SIDIS (Cond.appr. Exp.): Setup and parameters e+3He→e’+p(K)+X JLab 19/Mar/2010 III SBS Meeting BB: e-arm at 30o  = 45 msr GEM Tracker Gas Cherenkov Shower  GMn/PR-09-019 SBS: h-arm at 14o  = 50 msr GEM tracker excellent PID / RICH Hadron CALO DeLeo, Cisbani / HERMES RICH Event rate: ~104×HERMES 60 days of production expected stat. accuracy: 10*better than HERMES on proton Beam: 50 A, E=8.8 and 11 GeV (80% long. Pol.) Target: 65% polarized 3He  GEn(2)/PR-09-016  Luminosity: 1.4×1037 cm-2s-1

HERMES RICH in SBS (SIDIS Exp.) JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH (old GEM setup)

Challenges in large acceptance/high luminosity (SIDIS exp.) SBS Tracker rate 60 kHz/cm2 (bck, soft photons) RICH PID: high segmentation of photon detector (2000 PMT): Expected 35 extra hits/event from soft photons → Compton electrons in aerogel (50 ns gate width)  2-5% occupancy JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH (Jan/2009 estimation)

DeLeo, Cisbani / HERMES RICH To be done Present RICH performance ? Characterize the actual RICH and in particular evaluate the aerogel performance (transparency, refractive index …) ? Simulation Study rate capability of the RICH Evaluate required segmentation Are time information needed? Is the PCOS4 electronics still adequate? JLab 19/Mar/2010 III SBS Meeting DeLeo, Cisbani / HERMES RICH