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CLEO III RICH Detector and Test Beam Results. J.C.Wang representing M.Artuso, R.Ayad, F.Azfar, E.Dambasuren, A.Efimov, S.Kopp, G.Majumder, R.Mountain, S.Schuh, T.Skwarnicki, S.Stone, G.Viehhauser, J.C.Wang, J.Wu Syracuse University S.Anderson, Y.Kubota, A.Smith University of Minnesota
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CLEO III RICH Detectorand Test Beam Results J.C.Wang representing M.Artuso, R.Ayad, F.Azfar, E.Dambasuren, A.Efimov, S.Kopp, G.Majumder, R.Mountain, S.Schuh, T.Skwarnicki, S.Stone, G.Viehhauser, J.C.Wang, J.Wu Syracuse University S.Anderson, Y.Kubota, A.Smith University of Minnesota E.Lipeles California Institute of Technology T.Coan, V.Fadeyev, I.Volobouev, J.Ye Southern Methodist University
sg = 14 mrad N g = 12 C C CLEO III RICH Requirement • Cherenkov angle: more difficult to discriminate at higher momentum • Benchmark: 4sp/K separation at 2.8 GeV/c ~2s from dE/dX ~3.5s from RICH • LiF radiator: DQp-K = 12.8 mrad => strack ~ 3.8 mrad • Multiphoton per track: • => Design parameters: C C
The CLEO III RICH Proximity focussing with solid radiators. • LiF radiators • N2 expansion gap • CaF2 windows • CH4 /TEA photosensitive medium in MWPC • Pad read-out
Sawtooth image charged track charged track emerging g reflected g 10 mm 4mm Planar radiator Sawtooth radiator LiF Radiator • CH4+TEA photon sensitive band: 135nm - 165nm=> Fluoride crystal LiF as radiator: less chromatic dispersion • Well polished to have better transmission • Plane radiator region : 0.38 < |cosq| < 0.82 • sawtooth radiator region: |cosq| < 0.38 Plane image
Electronics VA-RICH chip produced by IDE AS • 64 channels serial differential current readout • Linear up to 3´105e input per pad • Low noise: ENC ~ 130e + 9e ´ C (pF) ~ 200 e • Total 3600 VA-RICH chips used for 230,400 channels Data board • 120 boards for final system, 8 boards for beam test • Bias voltage and current for VA-RICH chips • Flash ADC • Coherent noise subtraction 9U VME crate with Vx-works
Electronics Performance • Photon signal distribution is exponential average signal height ~ 40,000 e • Incoherent noise: ENC ~ 400 e => signal / noise ~ 100 • Coherent noise at beam test: ENC ~ 1000 e • In final system, coherent noise will be ENC ~ 400 e and subtracted on data board
Testbeam Setup • 3 radiators (1 plane, 2 sawtooth) + 2 photon detectors • Mounting on aluminum box resembles final scheme • pure N2 ( < 4 ppm O2) • For data-taking rotate in q and f • Parasitic µ beam (> 100 GeV) • Particle rate: 100 Hz/cm2 • 2 MWPCs as track reference • (sx,y~0.7mm, sangle~1mrad)
Event Display Plane Radiator, 30°track incident angle Sawtooth Radiator, normal incident track
Plane Radiator Resolution and Ng s =13.5 mr <N> = 15.5 s =4.5 mr • Data for 30° incidence angle • Tracks chosen to have full image containment • Photons on ring: photons with Q g within ±3s • Background on ring: ~ 9% => Ng = 14.0 • From MC: Error contribution from tracking system: 2.3 mrad C
Sawtooth Radiator Resolution and Ng • Photons on ring: photons with Q g within ±3s • strack in data slightly worse than MC (4.1 mrad). Still under study • Background on ring: ~9% • Limited acceptance of 55% CLEO III acceptance: N g = 21 => s ~ 4.0 mrad s =11.8 mrad <N> = 13.5 s =4.8 mrad C
Photon Number and Angle Resolution Limited acceptance at all angles for sawtooth radiator and 10° for plane radiator
Cherenkov Angle Resolution per Track • MC stracklower than data, may due to high backgroud at beam test, still under study • MWPC tracking resolution at beam test is worse than CLEO III • MC strack (corrected ) is simulated with full image containment and no error from tracking system CLEO III in this region
Summary • CLEO III RICH fulfill design goals • Status of construction: • Photon detector built 26/30, expect to finish at end of January, and tested by the end of April • Radiator (60%), expect finish at end of April, driven by sawtooth radiator • All VA_RICH hybrids received, nearly all tested • Designing final iteration of data board • CLEO III RICH completion expected: June, 99