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Introduction Special requirements Particle ID TOF RICH PreShower Preliminary results from 12 C- 12 C [1.5 AGeV]. Lepton ID in HADES High Acceptance Di-Electron Spectrometer. For the HADES Collaboration. Meson. Mass (MeV/c 2 ). G (MeV/c 2 ). C t (fm). dominant decay.
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Introduction Special requirements Particle ID TOF RICH PreShower Preliminary results from 12C-12C [1.5 AGeV] Lepton ID in HADESHigh Acceptance Di-Electron Spectrometer For the HADES Collaboration R. Gernhäuser (TU-München)
Meson Mass (MeV/c2) G (MeV/c2) Ct (fm) dominant decay Ge+e-/G r 769 150 1.3 2p 4.5 10-5 w 783 8.5 23.4 2p 7.1 10-5 f 1019 4.5 44.4 2K 2.9 10-4 The Challenge • Beam intensity 108/s • Nuclear reactions 106/s • Central collisions 105/s • Charged particles up to 200/evt • Leptons 104/s • Lepton pairs 103/s • Pairs from hadronic decay 10/s • pairs from r, w 1/s R. Gernhäuser (TU-München)
Second Level Trigger Online Lepton ID • Fast readout of all PID - detectors (10ms) • Real time processing with • Calibration • Pattern recognition • Position calculation • Transfer to Matching Unit • Decision and second level trigger distribution RICH Shower TOF Matching Unit R. Gernhäuser (TU-München)
TDC Start-Detektor t1 t2 The TOF Detector Catania (INFN - LNS) Milano (INFN, Univ.) Rez (CAS, NPI) Bratislava (SAS, PI) • 6 x 64 Scintillators stof : 90-140 ps • In beam start detector Diamond, d = 120mm, st = 66ps Talk by E. Berdermann R. Gernhäuser (TU-München)
X, Y, TOFonline calculation • Tundra VME-Bridge (SCV64) • Programmable Logik (XILINX-CPLD) • ADSP 21062 „Sharc“ (Analog Device) • RS485-Link to Matching Unit Position Window of +-5° for matching R. Gernhäuser (TU-München)
The RICH Detector CaF2 window VUV mirror Photon Detector : • CH4 MWPC • CsI cathode • 28.600 pads • 10 ms readout R. Gernhäuser (TU-München)
Single events in the RICH R. Gernhäuser (TU-München)
RICH online Lepton ID • Ring recognition algorithm (fixed radius) • Ring radius (+) inner and outer veto regions (-) • Correlation of pads • Summing correlation results • Threshold on positive and negative quality parameters R. Gernhäuser (TU-München)
Efficiency calibration(OEM) Photons produced by 600 AMeV 12C beam particles passing two different solid radiators R. Gernhäuser (TU-München)
2cm OEM Radiator beam beam line R. Gernhäuser (TU-München)
OEM results Radial distribution of photons represents spectral sensitivity of the detector N0 > 80 R. Gernhäuser (TU-München)
Lepton ID with TOF and RICH R. Gernhäuser (TU-München)
Lepton ID Software and Hardware [100%] Correlation of rings found by hardware or software image processing Efficiency of Ring recognition using matrix method @ suppression 100 Data from GEANT simulation R. Gernhäuser (TU-München)