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Particle identification — TOF detector of BESIII. Heng Yuekun hengyk@mail.ihep.ac.cn. Outline. Functions and target Structure and dimension Detector design TOF+TOF TOF+CCT CCT Experiment plan. Functions of TOF. Particle ID Give a fast trigger (Level-1) Reject cosmic ray background.
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Particle identification—TOF detector of BESIII Heng Yuekun hengyk@mail.ihep.ac.cn
Outline • Functions and target • Structure and dimension • Detector design • TOF+TOF • TOF+CCT • CCT Experiment plan
Functions of TOF • Particle ID • Give a fast trigger (Level-1) • Reject cosmic ray background
PID Target • Time Res.: • Target: • Upper limit of K/ separation(2) : 1.1GeV/c
Detector design • Two layers, two independent time: • Two options: • TOF+TOF • TOF+CCT • PMT connected directly
Dimension • Length: 1906mm • Coverage:~83% • Pieces:80 /layer • Place: • Space: 105mm • Reserved: 7mm • Thickness:49mm /layer
Scintillator:BC404 PMT: R5924 Scintillator and PMT
CCT introduction • Cherenkov Correlated Timing • Proposed in 1994 byK.Honscheid, M.Selen, M.Sivertz • Beam test in 1996 • no detector apply it • need more researches
CCT Principle & advantages • Cherenkov radiation: • Improve PIDGreater mass, Smaller angle,Longer time • Cheap • Simple
TOF+TOF TOF+CCT Comparison of K/ sep.
CCT threshold • Why threshold?Cherenkov radiation& Full reflection: • Under threshold, no signal • TOF layer give trigger signal
CCT Material • Quartz is best,but expensive • Plastic: 50-100ps • BC480:Atte. Length:4.5mCher/Scin.: 10/1
Preliminary Simulation • The Cher. light production and transit in BC480 by Geant4 Fig. Under the different hitting angle, the number of photon received by PMT. Fig. The histogram of the time when the photons hitting the PMT.
T0,Trig. T0,Trig. Scin. Scin. PMT PMT PMT PMT T1 T2 CCT Experiment Plan • Cosmic ray • Lead: • Two Scin.: • Coin. & Trig. • Collimation • Two CCT:T1-T2: Lead Cosmic ray
Summary • Target: 65ps, >1.1GeV • Structure: 2 layers, 2 timing • Two options: • TOF+TOF: experienced • TOF+CCT: better PID, more research • CCT Experiments plan