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The HERMES RICH: past and future

The HERMES RICH: past and future. PSHP Frascati, October 20 th -2010. Raffaele De Leo / University of Bari and INFN Bari. Overview of the HERMES RICH HERMES RICH performances HERMES RICH in SBS. HERMES Experimental Setup. 2 RICH identical modules.

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The HERMES RICH: past and future

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  1. The HERMES RICH: past and future PSHP Frascati, October 20th-2010 DeLeo, Cisbani / HERMES RICH Raffaele De Leo / University of Bari and INFN Bari

  2. Overview of the HERMES RICH • HERMES RICH performances • HERMES RICH in SBS DeLeo, Cisbani / HERMES RICH

  3. HERMES Experimental Setup DeLeo, Cisbani / HERMES RICH 2 RICH identical modules

  4. ’97: the HERMES dual radiator RICH proposal • focalized R = 2.2 m • n(aerogel)=1.03, C=242 mrad • n(C4F10)= 1.00137 • Npe (aerogel) = 10 • /(/ring) =1.2 % (4.1% / pe) • (/ring) = 3 mrad • C-Ck (7GeV,n =1.03) = 9mrad qC ±3s ring resolution

  5. HERMES RICH module layout 147 63 101 180 48 DeLeo, Cisbani / HERMES RICH 126 281 units in cm

  6. Radiators DeLeo, Cisbani / HERMES RICH Refractive Index n (633 nm)=1.03 Matsushita (hydrophobic) + C4F10 Gas, n(633 nm)=1.00137

  7. Optics DeLeo, Cisbani / HERMES RICH

  8. Photon Detector plane DeLeo, Cisbani / HERMES RICH PMT: 18 mm diameter

  9. ~20% of the HERMES RICH PMT array Light Collection DeLeo, Cisbani / HERMES RICH

  10. Electronics 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

  11. nov. ‘98

  12. In operation: 98-00, 02-08

  13. HERMES RICH performances DeLeo, Cisbani / HERMES RICH

  14. T  Cher. ’s  photoelectrons exp Npe (calc.) 10±2 (400 nm) = 2.3cm

  15. % /pe = geometrical contributions to C 1) pixel 2) focal plane a) (dq/q)opt.aber.= (d/R)2 = 0.5% b) (dq/q)surf.imp.= 0.3 % mirror alignment a)+b)(dq/q)mirror= 0.6 % / pe 3) point emiss. (dq/q) point= 0.7 % / pe

  16. aerogel opt. properties contrib.s to C • 1) n dispersion in the different tiles • 2) chromatic dispersion n() • 3) forward scattering • 4) tile surface irregularities aerogel Selected 850 tiles over 1200 11x11x1 cc from Matsushita 2 planes, 5 rows, 17 columns, 5 layers one aerogel radiator

  17. Hadron PID: HERMES RICH 5.5 GeV K+ 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 C4F10 Reference: NIMA 479 (2002) 511-530

  18. Pixel 2.3 Mirror0.6 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 exp. vs calc. angle resolution (%) HERMES c for single pe pe > 5 GeV Npe = 10 /=3.3%/pe DeLeo, Cisbani / HERMES RICH / = 1.1% /ring Largest error from pixel size (by design!)

  19. qC ring n (e+>5GeV) plot vs day n DeLeo, Cisbani / HERMES RICH

  20. average n (e+>5GeV) 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!

  21. pe reconst.starting point distribution e > 5 GeV DeLeo, Cisbani / HERMES RICH a real stable RICH ! DNpe< 0.2 0.3% in 10 years!

  22. HERMES RICH in SBS@HallA DeLeo, Cisbani / HERMES RICH

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

  24. SIDIS (Cond.appr. Exp.): Setup and parameters e+3He→e’+p(K)+X 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

  25. HERMES RICH in SBS (SIDIS Exp.) DeLeo, Cisbani / HERMES RICH (old GEM setup)

  26. 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 DeLeo, Cisbani / HERMES RICH (2009 estimation)

  27. 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? DeLeo, Cisbani / HERMES RICH

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