The CLEO-c Detector Steve Gray Cornell University BESIII Workshop January 13, 2004

BESIII WorkshopThe CLEO-c DetectorJanuary 13, New Era -> New Needs Need Quality Tracking AND Precision EM Calorimetery Large 93%  –Nearly hermetic Full-range Particle ID Simulate Alternatives Coordinate with Storage Ring Expect High Luminosity High Statistics Systematics Dominate Rare Decays Backgrounds Matter –Fakes –Feed-down –Combinatorics

BESIII WorkshopThe CLEO-c DetectorJanuary 13, T now, T later 93% of 4   p /p = dE/dx: 5.7% 93% of 4   E /E = = Trigger: Tracks & Showers Pipelined Latency = 2.5  s Data Acquisition: Event size = 25kB Thruput < 6MB/s CLEO III -> CLEO-c 83% of 4   % Kaon ID with 0.2%  85% of 4  For p>1 GeV

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO III  (4S) Typical Hadronic Event 10 tracks 10 showers

BESIII WorkshopThe CLEO-c DetectorJanuary 13,

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Drift Chamber Coordinated with IR 9796 sense wires 14 mm square cell 16 inner axial layers 31 stereo layers Outer cathode segmentation – z=1 cm; =2/8 Thin Inner Tube –0.12% X 0 60:40 Helium- Propane

BESIII WorkshopThe CLEO-c DetectorJanuary 13,

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Drift Chamber Performance Avg. residual 85 m –Best 65 m MC agreement Momentum Resolution – p/p=0.7% at 5 GeV/c – p/p=0.3% at 1 GeV/c –MS limited < 1.5 GeV/c dE/dx resolution –5.7% at min Ionizing –K– sep. at low p Drift Distance (mm) Residual (  m) DR3 All Layers

BESIII WorkshopThe CLEO-c DetectorJanuary 13, ZD – Inner Drift Chamber Charm -> lower momentum spectrum Multiple scattering limited p/p No vertexing needed Replace silicon with low-mass Z tracker Similar mass resolution More layers - better track recognition

BESIII WorkshopThe CLEO-c DetectorJanuary 13, ZD – Inner Drift Chamber 6 stereo layers: –r=5.3 cm – 10.5 cm –12-15 o stereo angle –|cos  < , 10 mm cells 1% X 0,.8mm Al inner tube 60:40 Helium-Propane 20 m Au-W sense wires 110 m Au-Al field wires Outer Al-mylar skin

BESIII WorkshopThe CLEO-c DetectorJanuary 13, ZD Drawing

BESIII WorkshopThe CLEO-c DetectorJanuary 13,

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Tracking with ZD P (GeV/c) Z0 (  )  p/p (%) ZD Calibration Underway –Residuals now < 200  Expect to outperform CLEO-c/CESR Project Description

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Cosmic Ray in ZD June 7, 2003

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO-c Event in ZD June 7, 2003

BESIII WorkshopThe CLEO-c DetectorJanuary 13, RICH Detector LiF Radiators –Flat and sawtooth –UV photons ( nm) N 2 expansion volume MWPC photo-detectors –TEA & CH 4   LiF radiator K/ 

BESIII WorkshopThe CLEO-c DetectorJanuary 13, RICH Detector

BESIII WorkshopThe CLEO-c DetectorJanuary 13,

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Resolution & Performance CLEO III data D->K without & with RICH cuts. 80% eff, 8:1 bkg suppression K- Separation (Chisq Difference)

BESIII WorkshopThe CLEO-c DetectorJanuary 13, RICH Performance Designed for B decay Excellent for D decay K –  separation Measured in data D*  D 0  + ; D 0  K -  + High efficiency Low  fake rates Combine with dE/dx CLEO-c B physics Kaon eff = 0.8 Kaon eff = 0.85 Kaon eff = 0.9

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CsI Calorimeter Projective Barrel Endcaps 4 photodiode readout Triple range ADCs Excellent –Photon finding –Electron ID –  0 &  reconstruction

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO CsI at a Glance ~7800 CsI(Tl) crystals ~ 5530 cm 3 (16X 0 ) 4 photodiode readout w/local preamps –229 crystals have 1 turned off (too noisy) –10 crystals have 2 turned off (6 in endcap) –0 have 3 or 4 turned off. –~7 “dead” crystals in CLEO III (all in endcaps, 5 near inner or outer radii) External summation/pulse shaping & TDC Total noise per crystal is ~0.5 MeV incoherent & ~0.2 MeV coherent Light output losses – calibrate away

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO II -> CLEO III Barrel unchanged TF removed, RICH inserted DR lengthened & narrowed Endplate material thinned Endcap repackaged Pushed back ~7 cm

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CsI for CLEO III & CLEO-c Barrel unchanged from CLEO II –But DR/Particle ID changes increase minimally obstructed barrel from 70% to 80% of 4 – “Good Barrel” is 14% bigger than CLEO II’s Endcaps repackaged for new I.R. superconducting quadrupoles – Thinner DR Endplate & better support design make less material in front than CLEO II – Only ~40%X 0, about 30% of CLEO II material – “Good Endcap” coverage |cos| = 0.85 to 0.93 Quality solid angle ~25% > than CLEO II New digitizing electronics

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CsI Performance

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Lessons from the Calorimeter Endcaps reconfigured for CLEO III Many crystals had lost signal with age –Glue joint had opened up –Endcap crystals reglued –Unable to fix barrel glue joints Material matters –Much improved Endcap performance

BESIII WorkshopThe CLEO-c DetectorJanuary 13,  ’  X,    +  - CLEO-c Muon System

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Trigger Programmable (FPGA), Pipelined Track and CsI cluster primitives: –Tracks (p t >150 MeV/c) –Low, Med, High shower clusters Combine to define triggers, e.g. >2 tracks + low shower >99% for hadronic events For CLEO-c –Reduce med & high thresholds –Add new neutral-only triggers –Implemented Tile Sharing

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Data Acquisition VME & FastBus front ends Designed for 1 kHz & 4 MB/sec Achieved 500 Hz & 6 MB/sec Several upgrades completed A few remain for Spring 2004

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Summary New era of high luminosity makes new demands on the detector. The CLEO-c Detector is state of the art, understood at a precision level, now taking data in the charm region.

BESIII WorkshopThe CLEO-c DetectorJanuary 13, Credits Calorimetry - Brian Heltsley DAQ - Tim Wilkson Tracking - Karl Ecklund, Dan Peterson Trigger - Topher Caulfield

BESIII WorkshopThe CLEO-c DetectorJanuary 13,  ’   +  - ;   e + e -

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO-c Event Picture D +   +  -

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO-c Event Picture D 0  

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO History CLEO I ( ) CLEO II ( ) –CsI calorimeter CLEO II.V ( ) –Silicon Vertex Detector CLEO III ( ) –RICH Particle ID –New IR & tracking: Silicon, Drift Chamber CLEO-c (2003-??) –Silicon replaced by ZD inner drift chamber Size of CLEO: 120–220 Collaborators

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CESR at Cornell

BESIII WorkshopThe CLEO-c DetectorJanuary 13, CLEO III Running for CLEO-c