1. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19991 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 E.Lipeles California Institute of Technology T.Coan, V.Fadeyev, I.Volobouev, J.Ye Southern Methodist University

2. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19992 CLEO III RICH Requirement Cherenkov angle: more difficult to discriminate at higher momentum Benchmark: 4   /K separation at 2.8 GeV/c ~2  from dE/dX~3.5  from RICH LiF radiator:   K = 12.8 mrad =>  track ~ 3.8 mrad Multiphoton per track: => Design parameters:     mrad    CC C C

3. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19993 The CLEO III RICH Proximity focussing with solid radiators. LiF radiators N 2 expansion gap CaF 2 windows CH 4 /TEA photosensitive medium in MWPC Pad read-out

4. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19994 LiF Radiator CH 4 +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 < |cos  | < 0.82 sawtooth radiator region: |cos  | < 0.38 Sawtooth image Plane image charged track reflected  Planar radiator charged track emerging  4mm Sawtooth radiator 10 mm

5. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19995 LiF Radiator

6. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19996 RICH Photon Detector

7. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19997 Electronics VA-RICH chip produced by IDE AS 64 channels serial differential current readout Linear up to 3  10 5 e 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

8. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19998 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

9. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 19999 Parasitic µ beam (> 100 GeV) Particle rate: 100 Hz/cm 2 2 MWPCs as track reference (  x,y ~0.7mm,  angle ~1mrad) Testbeam Setup 3 radiators (1 plane, 2 sawtooth) + 2 photon detectors Mounting on aluminum box resembles final scheme pure N 2 ( < 4 ppm O 2 ) For data-taking rotate in  and 

10. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199910 Testbeam Setup

11. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199911 Event Display Plane Radiator, 30 ° track incident angle Sawtooth Radiator, normal incident track

12. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199912 Plane Radiator Resolution and N  Data for 30° incidence angle Tracks chosen to have full image containment Photons on ring: photons with   within ±3  Background on ring: ~ 9% => N  = 14.0 From MC: Error contribution from tracking system: 2.3 mrad C  =13.5 mr = 15.5  =4.5 mr

13. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199913 Sawtooth Radiator Resolution and N   =11.8 mrad = 13.5  =4.8 mrad Photons on ring: photons with   within ±3   track in data slightly worse than MC (4.1 mrad). Still under study Background on ring: ~9% Limited acceptance of 55% CLEO III acceptance: N  = 21 => .0 mrad C

14. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199914 Photon Number and Angle Resolution Limited acceptance at all angles for sawtooth radiator and 10° for plane radiator

15. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199915 Cherenkov Angle Resolution per Track MC  track lower 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  track ( corrected ) is simulated with full image containment and no error from tracking system CLEO III in this region

16. Jianchun Wang, Syracuse UniversityDPF conference, Jan 7, 199916 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