1. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)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

2. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)2 Crystal BarrelCrystal Endcaps Preshower endcaps The CMS Preshower Detector Overview

3. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)3 Crystal Endcaps : Pseudorapidity 1.479 < η<3.0 138 Standard SuperCrystals (25 crystals) 14 Special SuperCrystals 3622 Crystals The CMS Preshower Detector The ECAL Endcaps

4. ATHENS HEP2003 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

5. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)5 The CMS Preshower Detector Physics Goals    BR(      for m H <150 GeV/c 2  π 0 ‘s from jets fake a photon from Higgs decay π 0  γγ : γγ separation in barrel : ~ cm (possible using crystal information only) γγ separation in endcaps : ~ mm (quite poor using crystal info)

6. ATHENS HEP2003 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 The Absorber : 3X 0 (η = 1.7)  95% conv. prob. 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%

7. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)7 The CMS Preshower Detector Detailed Structure

8. ATHENS HEP2003 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)

9. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)9 The CMS Preshower Detector Micromodules 1000 micromodules to be made in Greece by Demokritos & Un. of Ioannina Micro-module Schematic Real

10. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)10 The CMS Preshower Detector Ladders Ladder Schematic Real

11. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)11 The CMS Preshower Detector Layout Each end cap : 4.5m 2

12. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)12 The CMS Preshower Detector Silicon Sensors Design

13. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)13 The CMS Preshower Detector Silicon Sensors Mask

14. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)14 The CMS Preshower Detector Silicon Sensors Parameters

15. ATHENS HEP2003 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)

16. ATHENS HEP2003 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]

17. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)17 The CMS Preshower Detector Silicon sensors measurement setup

18. ATHENS HEP2003 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 Half of them have been given to University Of Ioannina At this point in Demokritos we have 87 sensors within specifications (17 from IMEL and 70 from ELMA-Russia) C-V I-V Final goal to deliver 1000 sensors to the CMS collaboration

19. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)19 Depletion voltage for each strip of the 34 sensors (Volts) The CMS Preshower Detector Silicon sensors characteristics(2) Breakdown voltage for each strip of the 34 sensors (Volts)

20. ATHENS HEP2003 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)

21. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)21 C.R.I.S.T.A.L. Local Center Software Architecture User Applications Product Managers Local Center Manager Data Duplication Manager Instrument Agents Digital Control Panels Configuration Database Production Database Main Database Objectivity V5.2 Virtual Instruments Labview V5.1 Orbix V3.0.1 CORBA Physical Instruments Central Repository Implemented in Windows 2000 The CMS Preshower Detector Silicon sensors

22. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)22 The CMS Preshower Detector Expected response for single γ A single 30 GeV p T (η = 1.7) photon on the SE and EE

23. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)23 The CMS Preshower Detector Expected response for π 0 Two closely spaced photons (~1 cm) from the decay of a 30 GeV p T π 0 (η = 1.7)

24. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)24 The CMS Preshower Detector Photon (coming from π 0 ) separation in Preshower photon Unfortunately these are not ‘typical’ events PreShower strip = 6 cm x 2 mm 00  =1.7  =2.4

25. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)25 The CMS Preshower Detector π 0 /γ Preshower cluster energy distribution Indication of separation power: Variation of Width with Et Et=20,  =1.7 Et=50,  =1.7 0/0/ 0/0/ Clearly lose separation power at higher Et (even worst at higher η)

26. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)26 The CMS Preshower Detector π 0 rejection algorithm particle Layer1 (x)Layer2 (y) Preshower information: Energy (fraction) in 11 strips 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’ Central strip definition: around a ‘Central’ strip

27. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)27 The CMS Preshower Detector Neural Network π 0 rejection algorithm Use Neural Network (Feed-Forward Back-Propagation) 23 input variables: 22 PreShower + 1 ECAL crystals For each strip i in layer 1: E i /  i=1..11 E i For each strip i in layer 2: E i /  i=1..11 E i Crystal information: S 1 /S 25 ‘Central’ strip: extrapolation from crystals

28. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)28 The CMS Preshower Detector Neural Network output Performance: Look for  0 - rejection @ 90%  -efficiency Et=20,  =1.7Et=60,  =2.4 00 00  

29. ATHENS HEP2003 A.Kyriakis (Preshower INP Demokritos group)29 The CMS Preshower Detector π 0 rejection vs E t and η CMSIM : Detector simulation based on GEANT ORCA : Detector Reconstruction

30. ATHENS HEP2003 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 π 0 rejection and will be soon implemented in the official CMS reconstruction Software