RICH 2002, Pylos, Greece1 Steven Blusk for the BTeV Collaboration Design of the BTeV RICH and its...

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Transcript of RICH 2002, Pylos, Greece1 Steven Blusk for the BTeV Collaboration Design of the BTeV RICH and its...

  • Steven Blusk for the BTeV CollaborationDesign of the BTeV RICH and its Expected Performance

  • The BTeV CollaborationBelarussian State- D .Drobychev, A. Lobko, A. Lopatrik, R. ZouverskyUC Davis - J. Link, P. YagerUniv. of Colorado at BoulderJ. CumalatFermi National Lab J. Appel, E. Barsotti, CN Brown, J. Butler, H. Cheung, G. Chiodini, D. Christian, S. Cihangir, I. Gaines, P. Garbincius, L. Garren, E. Gottschalk, A. Hahn, G. Jackson, P. Kasper, P. Kasper, R. Kutschke, SW Kwan, P. Lebrun, P. McBride, L. Stutte, M. Votava, M. Wang,J. YarbaUniv. of Florida at Gainesville P. Avery University of Houston K. Lau, B. W. Mayes, J. Pyrlik, V. Rodriguez, S. SubramaniaIllinois Institute of TechnologyRA Burnstein, DM Kaplan, LM Lederman, HA Rubin, C. White Univ. of Illinois- M. Haney, D. Kim, M. Selen, J. WissIndiana University RW Gardner, DR Rust Univ. of Insubria in Como-P. Ratcliffe, M. RovereINFN - Frascati- M. Bertani,L. Benussi, S. Bianco, M. Caponero,F. Fabri, F. Felli, M. Giardoni, A. La Monaca, E. Pace, M. Pallota,A. Paolozzi, A. Scicutelli INFN - Milano G. Alimonti,M. Citterio, P. DAngelo, S. Magni,D. Menasce, L. Moroni, D. Pedrini,M. Pirola, S. Sala, L. Uplegger INFN - Pavia - G. Boca, G. Cossail, E. Degliantoni, PF Manfredi, M. Manghisoni, M. Marengo, L. Ratti, V. Re,V. Speziali, G. TraversiINFN - Torino N. Cartiglia, R. Cester,F. Marchetto, R. Mussa, N. PastroneIHEP Protvino, Russia A. Derevschikov, Y. Goncharenko,V. Khodyrev, A. Meschanin,L. Nogach, K. Shestermanov,L. Soloviev, A. Vasiliev University of Iowa C. Newsom, R. Braunger University of Minnesota V. V. Frolov, Y. Kubota, R. Poling, A. Smith Nanjing Univ. (China) T. Y. Chen, D. Gao, S. Du, M. Qi, BP. Zhang, JW Zhao Ohio State University K. Honscheid, & H. Kagan Univ. of Pennsylvania W. Selove Univ. of Puerto Rico A. Lopez, & W. Xiong Univ. of Science & Tech. of China - G. Datao, L. Hao, Ge Jin, L. Tiankuan, T. Yang, XQ YuShandong Univ. (China) CF Feng, Yu Fu, Mao He, JY Li, L. Xue, N. Zhang, & XY Zhang Southern Methodist University - T. Coan SUNY Albany - M. Alam Syracuse University M. Artuso, C. Boulahouache,O. Dorjkhaidav K. Khroustalev, R.Mountain, R. Nandakumar, T. Skwarnicki, S. Stone, JC Wang, H. Zhao Univ. of Tennessee K. Cho, T. Handler, R. Mitchell Tufts Univ. A. Napier Vanderbilt University W. Johns, P. Sheldon, K. Stenson, E. Vaandering, M. Webster Wayne State University G. Bonvicini, D. Cinabro University of Wisconsin M. Sheaff Yale University J. Slaughter York University S. Menary

  • Physics of BTeV BTeV will vastly improve the constraints on the CKM angles by making precision measurements of both the sides and the angles a, b, g. over-constrain (r,h). Measurements and searches for rare and SM forbidden decays Beyond the SM Physics. B factories will provide valuable input on sin(2b) and Vub, but they cannot compete with a hadron collider on measuring a, g, and searches for new physics (even by 2007). - They dont produce BS - s(bb) is ~10,000X larger at the Tevatron than at U(4S)

  • B Production at the Tevatronb cross section ~ 100 mb at 2 TeV 2x1011 bs per 107 sec at L=2x1032 cm-2 s-1.

  • B Physics Detector Wish List

    Detector PropertyPrecision 3D TrackingExcellent Particle ID (K, p, p, e, m)Excellent calorimetryDetached Vertex trigger at lowest level trigger


  • The BTeV Detector

  • RICH Specifications Momentum Range of Interest * p > 2-3 GeV for CP tagging * p < 70 GeV clean separation of 2-body modes: Bpp, Kp, KK. Minimize material in front of ECAL Longitudinal space available ~3 meters Desirable to detect Cerenkov photons in the visible range (minimize chromatic error, less sensitive to contaminants, etc) Well-suited for a Ring Imaging Cerenkov DetectorTagging kaons in BTeV Acc.

  • RadiatorsLarge momentum coverage requires a low index of refraction gas radiator We chose C4F10 because:* heaviest gas which has high transparency in the visible * wide usage in other HEP expts (e.g. Delphi, HERA-B, HERMES, LHC-b). For momenta below 9.5 GeV/c neither K nor P radiate in C4F10 Separate liquid radiator for K/P separation below 9.5 GeV/c

  • The BTeV RICHArrays of 163-channel HPDs (~1000 in total)PMT Arrays (~5,000 in total)Spherical mirrorsC5F12 Liquid RadiatorC4F10 gas volume Photons from gas are reflected off mirrors and focused at the HPD plane. Photons from liquid are directly detected in the PMTs.

  • Photon AnglesTrack from InteractionHPDArrayPMTArrayLiquid radiator photons are detected in PMT array.Liquid RadiatorGas Radiator VolumeGas radiator photons are detected in HPD array.Mirror

  • Gas RadiatorGas: C4F10 (n=1.00138): * K/p separation for 3 < p
  • Detecting Gas Photonswith HPDs* See talk by Ray Mountain Started with 61-channel HPD that LHC-b and DEP developed. We worked with DEP to develop 163-ch version| which would meet BTeVs requirements.

    Cross-focused onto hexagonal pixels Signal: ~5000 e- in Silicon. Readout system is being developed by Syracuse in collaboration with IDE AS Norway.HPDeg163 channels~1.5 mm-20 kV

  • HPD Hexad Mu-metal shieldReadout Boards are mounted hereHPDVA_BTEV ASICs (AS&D) Full HPD Array

  • HPD Readout VA_BTeV ASIC being developed in collaboration with IDE AS Norway (independent from HPD development) Initial tests indicate that ~500 e- noise level be achieved. Threshold for each channel is adjustable. Readout is binary (ON or OFF) Testing of first prototypes is underway at Syracuse.HPDReadoutBoardVA_BTeV chip

  • More on HPD Readout Discharge of FE chip requires 2 beam crossings, so a hit channel is dead for the next crossing. Simulated effect @ L=2x1032 cm-2 s-1. Find
  • Liquid RadiatorC5F12 (n=1.24): * Extends P/K separation to p
  • Detecting Liquid Photons -- PMTs Expect to use 3 tubes. Shielding necessary ( |B| < 15 G in PMT region) Expect s(qgc) ~ 6 mrad, N(g)~15/trk s(qtrkc) ~ 1.6 mradPMT Layout in BTeVMu-metal shields3

  • Magnetic Shielding of PMTsUnshieldedUnshieldedB Trans.PMTs from 4 different manufacturers4. Long.Bmax=15 G

  • Preliminary Conceptual Tank DesignPMT ArraysHPD Arrays

  • Liquid Radiator Conceptual Design 1 cm of C5F12 3 mm Carbon Fiber front window & 3 mm quartz back window Split into 5 volumes to reduce pressure. Structure is reinforced by CF posts Total Material Budget: X0 ~ 8.7% Simulations indicate negligible impact on p0 reconstruction since electrons from g conversions are only in a very weak magnetic field.

  • Progress with Mirrors Measurements being taken on the test bench of the TA2 group at CERN. Several mirrors under study COMPAS: glass, glass+foam back., CMA: Carbon fiber Initial tests show that they meet spot size spec.Rcurv=660 cmWork being done by INFN Torino group~60 cm

  • Expected Performancefrom Simulations

  • Efficiency vs Fake RateClean separation of B pp from BKp and BKK For example: e(B pp): 80% Kp Rejection ~ 95% KK Rejection > 99% The latter is important because BsKK lies on top of Bpp signalB pp Simulation w/ 2 minimum bias events.Gas Radiator & HPDsK+p-K+K-

  • Low Momentum K/P separation using Liquid Radiator & PMTsK and P cannot be separated below 9.5 GeV/c in gas system. Our simulations showed that we could improve eD2 by ~25% for BS and ~10% for B0 using liquid radiator.Mom. < 9 GeV/c

  • Expectations for eD2Error on CP Asymmetry

    Tag TypeeD2B0BSAway Side Kaon Tag6.0%5.8 %Same Side Kaon (Pion) Tag1.1%4.5%Away Side Muon Tag0.8%1.3%Jet Charge1.4%0.4%Total9.2 %12.1 %BTeV Expected10 %13 %

  • Test Beam May 2003ConcreteSupport BlocksHPDEnclosureMirrorAssemblyFrontEntrance Window ~15 HPDs to cover full Cerenkov ring ~100 GeV p beam Will measure: * resolution on Cerenkov angle * photon yield Well also scan the mirror to check sensitivity Construction underway.

  • Summary The BTeV RICH uses : gas system: C4F10 gas and HPDs, and liquid system: C5F12 and PMTs to achieve excellent p/K/P separation for all relevant momenta less than 70 GeV/c. Recent addition of the liquid radiator system will improve eD2 for CP tag by ~25% for BS and ~10% for B0. Initial tests of HPDs/PMTs look encouraging (see talk by R. Mountain) Test beam next year to validate detector design and simulations.

  • Why did we punt on Aerogel?Both gas & aerogel photons were detected in the HPDs After removing photons which were consistent with more than 1 track, aerogel provided essentially no K/P separation The aerogel rings have too few photons to compete with the bright gas ringsLow mult. eventHigh mult. event

  • Alternate solution fordetecting gas photons(MA-PMT16) Larger active region than 1st gen. lens system not required Viable backup to HPDs slightly worse position resolution.. Currently being tested at Syracuse.