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The CMS Preshower Detector Overview

The CMS Preshower Detector Overview. CERN Armenia : Yerevan Physics Institute Belarus : Minsk University Greece : N.C.S.R. Demokritos U. of Ioannina India : Bhabha Atomic Research Centre U. of Delhi Russia : JINR Dubna

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The CMS Preshower Detector Overview

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  1. The CMS Preshower Detector Overview CERN Armenia : Yerevan Physics Institute Belarus : Minsk University Greece :N.C.S.R. Demokritos U. of Ioannina India :Bhabha Atomic Research Centre U. of Delhi Russia : JINR Dubna Taiwan : National Central University National Taiwan University A.Kyriakis (Preshower INP Demokritos group)

  2. Crystal Endcaps Crystal Barrel The CMS Preshower Detector Overview Preshower endcaps A.Kyriakis (Preshower INP Demokritos group)

  3. The CMS Preshower Detector The ECAL Endcaps Crystal Endcaps : Pseudorapidity 1.479 < η<3.0 138 Standard SuperCrystals (25 crystals) 14 Special SuperCrystals 3622 Crystals A.Kyriakis (Preshower INP Demokritos group)

  4. The CMS Preshower Detector Fiducial Coverage The fiducial coverage of SE extends from 1.653<η<2.6 A.Kyriakis (Preshower INP Demokritos group)

  5. tt p g gg The CMS Preshower Detector Physics Goals π0‘s from jets fake a photon from Higgs decay π0γγ : γγ separation in barrel : ~ cm (possible using crystal information only) γγ separation in endcaps : ~ mm (quite poor using crystal info) BR(H gg ) ~ 10-3for mH<150 GeV/c2 A.Kyriakis (Preshower INP Demokritos group)

  6. The CMS Preshower Detector Design Criteria The Preshower acts as a sampling calorimeter: Lead absorbers : initiate EM showers Silicon sensors : act as energy sampling devices g g The Absorber : 3X0(η = 1.7) 95% conv. prob. g • The silicon sensors : • Fabrication on 4” wafers • Large Area : 63 mm x 63 mm • Thickness : 320 μm • Number of Strips : 32 • Strip Capacitance ~ 42pF • Occupancy ~ 1% A.Kyriakis (Preshower INP Demokritos group)

  7. The CMS Preshower Detector Detailed Structure A.Kyriakis (Preshower INP Demokritos group)

  8. The CMS Preshower Detector Sensor Overlap • 1-D sensor overlapping • 2mm wide dead space in one direction • tile + ceramic + sensor+PACE micromodule • 4288 identical micromodules in the complete SE (both endcaps) A.Kyriakis (Preshower INP Demokritos group)

  9. Real Schematic Micro-module The CMS Preshower Detector Micromodules 1000 micromodules to be made in Greece by Demokritos & Un. of Ioannina A.Kyriakis (Preshower INP Demokritos group)

  10. Real Schematic Ladder The CMS Preshower Detector Ladders A.Kyriakis (Preshower INP Demokritos group)

  11. The CMS Preshower Detector Layout Each end cap : 4.5m2 A.Kyriakis (Preshower INP Demokritos group)

  12. The CMS Preshower Detector Silicon Sensors Design A.Kyriakis (Preshower INP Demokritos group)

  13. The CMS Preshower Detector Silicon Sensors Mask A.Kyriakis (Preshower INP Demokritos group)

  14. The CMS Preshower Detector Silicon Sensors Parameters A.Kyriakis (Preshower INP Demokritos group)

  15. The CMS Preshower Detector Electronics PACE is the compination Of 2 chips: Delta and PACE_AM Delta front-end + Programmable biasing And calibration PACE_AM 160 column, 32 deep FIFO. Programmable biasing, mux 40MHz clock New Design in submicron tecnology (will be delivered for testing in May 2003) A.Kyriakis (Preshower INP Demokritos group)

  16. The CMS Preshower Detector Electronics (Submicron Technology) Delta3.. area = 17mm2, [Delta 2 = 21mm2] PACEAM3.. area = 30mm2, [PACEAM2 = 60mm2] A.Kyriakis (Preshower INP Demokritos group)

  17. The CMS Preshower Detector Silicon sensors measurement setup A.Kyriakis (Preshower INP Demokritos group)

  18. The CMS Preshower Detector Silicon sensors characteristics(1) 34 Sensors manufactured by Demokritos (Institure of Microelectronics-IMEL) while the masks were designed by INP C-V Half of them have beengiven to University Of Ioannina At this point in Demokritos we have 87 sensorswithin specifications (17 fromIMEL and 70 from ELMA-Russia) I-V Final goal to deliver 1000 sensors to the CMS collaboration A.Kyriakis (Preshower INP Demokritos group)

  19. The CMS Preshower Detector Silicon sensors characteristics(2) Depletion voltage for each strip of the 34 sensors (Volts) Breakdown voltage for each strip of the 34 sensors (Volts) A.Kyriakis (Preshower INP Demokritos group)

  20. The CMS Preshower Detector Silicon sensors characteristics(2) Breakdown voltage for each strip of the 34 sensors Leakage Current at Depletion voltage for each strip of the 34 sensors (Ampers) Leakage Current at 300V for each strip of the 34 sensors (Ampers) A.Kyriakis (Preshower INP Demokritos group)

  21. Data Duplication Manager Labview V5.1 User Applications Product Managers Virtual Instruments Orbix V3.0.1 Local Center Manager CORBA Instrument Agents Physical Instruments Central Repository Main Database Production Database Configuration Database Digital Control Panels Objectivity V5.2 The CMS Preshower Detector Silicon sensors C.R.I.S.T.A.L. Local Center Software Architecture Implemented in Windows 2000 A.Kyriakis (Preshower INP Demokritos group)

  22. The CMS Preshower Detector Expected response for single γ A single 30 GeV pT (η = 1.7) photon on the SE and EE A.Kyriakis (Preshower INP Demokritos group)

  23. The CMS Preshower Detector Expected response for π0 Two closely spaced photons (~1 cm) from the decay of a 30 GeV pTπ0 (η = 1.7) A.Kyriakis (Preshower INP Demokritos group)

  24. The CMS Preshower Detector Photon (coming from π0) separation in Preshower PreShower strip = 6 cm x 2 mm photon =1.7 0 =2.4 Unfortunately these are not ‘typical’ events A.Kyriakis (Preshower INP Demokritos group)

  25. The CMS Preshower Detector π0/γ Preshower cluster energy distribution Et=20,=1.7 Et=50,=1.7 0/ 0/ Indication of separation power: Variation of Width with Et Clearly lose separation power at higher Et (even worst at higher η) A.Kyriakis (Preshower INP Demokritos group)

  26. The CMS Preshower Detector π0rejection algorithm Preshower information: Energy (fraction) in 11 strips particle around a ‘Central’ strip Central strip definition: • Extrapolate a straight line from ECAL cluster barycenter to point (0,0,0) • Find the intersection of this line with the two Preshower planes • The strip closest to the intersection point is defined as the ‘Central Strip’ Layer1 (x) Layer2 (y) A.Kyriakis (Preshower INP Demokritos group)

  27. The CMS Preshower DetectorNeural Network π0 rejection algorithm Use Neural Network (Feed-Forward Back-Propagation) 23 input variables: 22 PreShower + 1 ECAL crystals ‘Central’ strip: extrapolation from crystals For each strip i in layer 1: Ei / i=1..11 Ei For each strip i in layer 2: Ei / i=1..11 Ei Crystal information: S1/S25 A.Kyriakis (Preshower INP Demokritos group)

  28. The CMS Preshower DetectorNeural Network output Et=20,=1.7 Et=60,=2.4  0  0 Performance:Look for 0-rejection @ 90% -efficiency A.Kyriakis (Preshower INP Demokritos group)

  29. The CMS Preshower Detectorπ0 rejection vs Et and η CMSIM : Detector simulation based on GEANT ORCA : Detector Reconstruction A.Kyriakis (Preshower INP Demokritos group)

  30. The CMS Preshower Detector Conclusions • Demokritos is able to manufacture high quality Silicon Sensors to be used in the CMS-Preshower project • A part of the sensors will be manufactured in Demokritos and the rest will be bought by ELMA- Russia and Hammamastu • Neural Network techniques gave good results in π0 rejection and will be soon implemented in the official CMS reconstruction Software A.Kyriakis (Preshower INP Demokritos group)

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