1. Cherenkov Detectors for b Physics Sacha Kopp University of Texas at Austin cos  C = 1/(n  ) CC “radiator” “photo-detector”

2. 2/30 Good Ol’ Days of Cherenkov Counters Threshold Counter Velocity Selector “Fitch Counter”

3. 3/30 Ring-Imaging Cherenkov Detectors (RICH) First detectors:  DELPHI “RICH” at LEP  SLD “CRID” at SLC Both TMAE-based TPC’s, dual radiator Original proposal in J. Séguinot & T. Ypsilantis, Nucl. Instr. Meth. 142, 377 (1977) figures from J. Séguinot CERN-89-12

4. 4/30 BaBar “Detector of Internally-Reflected Cherenkov-light (DIRC)”

5. 5/30 DIRC Principle ee  ee    t ~ 300 ns about collision time  t ~ 8 ns about collision time figures from J. Schwiening, Nucl. Instr. Meth. A502, 67 (2003)

6. 6/30 BaBar DIRC Performance figures from B. Ratcliff, RICH2004 Conference

7. 7/30 Belle Detector SC solenoid 1.5T CsI(Tl) 16X 0 TOF counter 8GeV e - Si vtx. det. 3 lyr. DSSD μ/K L detection 14/15 lyr. RPC+Fe Tracking + dE/dx small cell + He/C 2 H 5 3.5GeV e + Aerogel Cherenkov cnt. n=1.015~1.030 A K  =  0.101±0.025±0.005 3.9

8. 8/30 Particle Identification at Belle slide taken from Blair Ratcliff, RICH 2004 Conference p/K/π separation is based on Likelihood ratio: LR(K)= L(K)+L(π) L(K)

9. 9/30 CLEO-III RICH Detector Fit inside existing CsI calorimeter (102 cm ID) Limit to 13% X 0 Needed <20 cm depth  C = 12.8 mrad in LiF Coverage for daughters of B mesons produced at rest: p max ~ 2.65 GeV/c

10. 10/30 LiF + TEA Detector

11. 11/30 Alkali-halide crystals  low dispersion (  n/  = 0.0023 nm -1 ): cos  C = 1/  n( )  Can fabricate with good transparency, large sizes (after many yrs’ effort) Sole example in world: previous effort by Sauli @ FNAL E605,  n pe  ~ 1-2

12. 12/30 Images are conic intersections distorted and truncated by refractive effects. Total internal reflection for  trk < 6°  sawtooth radiator  Also reduces chromatic aberrations Radiator Optics Image in photon detectors: charged track Sawtooth image in detectors: primary arcs secondary arcs (+1 reflection) A. Efimov and S. Stone, Nucl. Instr. Meth. A371, 79 (1996)

13. 13/30

14. 14/30 Multiwire chamber 20  246 cm 2 CH 4 + TEA gas (no blinds/cloisons) Total 15 m 2 of chambers <8% “dead area” No observed aging of components from corrosive TEA Cathode pad readout (80% coupling) Achieve effective  gain  ~ 10 5 Photon Detector MWPCs S.K. & Georg Viehhauser

15. 15/30 Single Photo-electron Detection Assume:  electronics  = 400 e   chamber gain ~ 40,000 Charged ptcles ionize ~ 62 e - /cm in CH 4 Single  ’s: large statistical fluctuations. Gain limit g~10 5 due to  feedback (R.Arnold et al, Nucl. Instr. Meth. A270, 255 (1980). originally seen by H. Schlumbohm, Z. Phys. 151, 563 (1958) Analog readout of signal  accurate  clustering in RICH  identification of charged particles = e  4  /g = 96%

16. 16/30 Readout Electronics VA_RICH chip  variation of chip used for Si tracking detectors (input C det )  daisy-chain multiple chips into one VME controller  input protection (protect against chamber sparking)  dynamic range 650,000 e  Marina Artuso

17. 17/30 Electronics Performance 230,400 channels in CLEO RICH  onboard sparsification. Coherent noise subtraction was an improvement, also adopted for CsI  incoh  ~ 2.6 ADC counts ~ 400e  Marina Artuso & Silvia Schuh

18. 18/30 Parasitic µ beam (> 100 GeV). 2 MWPCs as track reference Demonstrated  n pe ~12 expected for CLEO-III  Sawtooth works as expected given clarity measurements. RICH Beam Test E866 beam dump MWPC1MWPC2 Trigger counters Vetocounter 1.5 m RICH concrete   N  = 13.5  =4.8 mr CC CC NN NN

19. 19/30 photo of beam test Beamline Elliot Lipeles Ray Mountain Silvia Schuh Alex Efimov

20. 20/30 Beam Test Events Planar Sawtooth M. Artuso et al Nucl. Instrum. Meth. A441, 374 (2000)

21. 21/30 Sheldon Stone Yuri Maravin Jeff Cherwinka Rachid Ayad

22. 22/30 Alex Smith Ray Mountain Georg Viehhauser Silvia Shuh

23. 23/30 Ray Mountain Jeff Cherwinka Georg Viehhauser

24. 24/30 First CLEO-III Data ee  eeee  ee taken from T. Skwarnicki, BCP Conference, Taipei, Dec. ‘99

25. 25/30 CLEO-III RICH Performance M. Artuso et al, Nucl. Instrum. Meth. A554: 147-194 (2005) BDKBDK BDBD Beam Constrained Mass (GeV/c  ) A. Bornheim et al, Phys. Rev. D68:052002 (2003)

26. 26/30 LHCb Layout b Exp’ts at Hadron Machines CERN LHC Proposed for FNAL Tevatron Purpose is to collect large samples to over-constrain Unitarity Triangle and search for New Physics.

27. 27/30 Particle ID in Forward b Experiments Gas C 4 F 8 O n=1.00138 Liquid C 5 F 12 n=1.24 (proximity focused) (mirror-focused) BTeV RICH

28. 28/30 -20,000 V -19,890 V -15,800 V ground Vacuum-based Photodetectors 0pe 1pe 2pe 3pe BTeV HPD readout with VA_RICH 87 mm 125 mm e-e-  +60 V Silicon diode HPD: DEP PP0380AT figures from T. Skwarnicki, presentation at DOE review of BTeV

29. 29/30 MAPMTs Beam (120 GeV p) Glass mirror Gas tank: C 4 F 8 O and Argon Beam Test of BTeV RICH figures from T. Skwarnicki, presentation at DOE review of BTeV J.C. Wang R. Mountain S. Blusk

30. 30/30 Looking Back The CLEO-III/c RICH detector works well We all made it through a challenging project  working beyond edge of demonstrated technology  rising/falling of semiconductor industry  learning curve in chambers, crystals, gas systems, electronics, …  near-miss not choosing CsI or other photocathode I would like to express my gratitude and admiration for my coworkers at Syracuse, and those that followed to make the RICH a success. All of us grateful for the job Sheldon did  supporting our research  encouraging “discussion”  spreading infectious enthusiasm  maintaining focus  providing “guidance” to young turks I wish Sheldon & Syracuse group many years of productive research