1. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 1 Simulation Study of Digital Hadron Calorimeter Using GEM Venkatesh Kaushik* University of Texas at Arlington Introduction GEM Geometry Implementation in Mokka GEM Single Pion Studies Conclusion *On behalf of the HEP Group at UTA

2. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 2 Introduction LC physics topics require –Distinguish W from Z in two jet final states  Good jet mass resolution –Higher Jet energy resolution; –Excellent jet angular resolution Energy flow algorithm is one of the solutions –Replace charged track energy with momentum measured in the tracking system Requires efficient removal of associated energy cluster  Good position resolution Higher calorimeter granularity –Use calorimeter only for neutral particle energies –Best known method for jet energy resolution improvement Large number of readout channel will drive up the cost for analogue style energy measurement  Digital HCAL Tracking calorimeter with high gain sensitive gap

3. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 3 UTA Simulation Effort S. Habib and VK have been working on this project for their Master’s theses –Mokka geometry database downloaded and installed –Simple GEM geometry implemented –Completed single pion studies using GEM and TESLA- TDR geometry. Various software has been packaged and released

4. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 4 CERN-open-2000-344, A. Sharma Large amplification Gas Electron Multiplier (GEM) Exploring the possibility of using GEM in hadron calorimetry GEM DHCal Progress and Plans, A.White (Session IV, Jan 11, 8:30-10:00)

5. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 5 Single Pion Studies GEM and TESLA TDR Geometry Single pion events using Mokka particle gun command –Incident energy range: 5 – 150 GeV Developed analysis programs to read total energies deposited per pion for each incident energy –Gain of the GEM detector given (3500) as a detector property –EM-HAD relative weighting factor necessary –Mean energy v/s incident pion energies –Energy conversion from the slope of the straight line –Conversion factors are 2.4% (for GEM) and 3.47% (for TDR) and agree with the computed sampling fraction

6. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 6 TESLA TDR Geometry Existing Geometry of Digital Hadron Calorimeter 8 staves each having 5 modules Each module has 40 layers, each layer with plates of 18 mm of Fe and 6.5 mm of polystyrene scintillator Hcal hits are collected Polystyrene scintillator, in cells of ~1 cm 2 Hcal end-caps are build as 32 side Polyhedrons, with 40 layers inside, each layer with plates of 18 mm of Fe and 6.5 mm of Polystyrene scintillator Courtesy: Paulo deFrietas Replace with GEM

7. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 7 GEM Geometry Implementation Mechanics in Mokka TDR / Hcal02 Model chosen for modification Fe-GEM sub-detector instead of the existing Fe-Scintillator New driver for the HCal02 sub-detector module Local database connectivity for HCal02  Database downloaded and implemented at UTA Courtesy: Paulo deFrietas

8. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 8 Double GEM Geometry 0. 00 5 1.01.0 Cu Kapton ArCO 2 G10 0. 00 5 6.5mm Simple GEM 3.4 mm ArCO 2 GEM 3.1 mm Detailed GEM Simple GEM uses average density

9. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 9 Comparison of Detailed and Simple GEM Geometries Detailed GEM 75GeV  25.2sec/event for Simple GEM v/s 43.7 sec/event for Detailed GEM Responses look similar for detailed and simple GEM geometry Simple GEM sufficient =0.80  0.007MeV =0.81  0.008MeV Simple GEM 75GeV 

10. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 10 Single Pion Cell Energy Deposit in GEM HCal GEM cell energy deposit is functional Used for discharge studies

11. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 11 Incident pion energy  50 GeV. 2000 events Live energy deposit in Ecal and Hcal for TESLA TDR geometry, Live energy (MeV)  Live Energy Deposit:TESLA TDR Mean : 8.6 MeV/event Mean: 2.44 GeV/event EM HAD  E EM  E HAD

12. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 12 E Live =  E EM +  E HAD, Live energy (MeV)   E Live Mean : 1.92 GeV/event TOTAL Live Energy Deposit:TESLA TDR

13. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 13 CERN GDD group GEM gains HV=420V G=3500

14. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 14 Live Energy Deposit: GEM TOTAL Mean : 4.87 GeV/event Two Gaussian Fits G = 3500 E Live =  E EM +  GE HAD, Live energy (GeV)   E Live

15. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 15 EM-HAD Weighting Factor E Live =  E EM + W  GE HAD Obtained the relative weight W using two Gaussian fits to EM only v/s HAD only events Perform linear fit to Mean values as a function of incident pion energy Extract ratio of the slopes  Weight factor W E = C* E Live

16. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 16 Gaussian Fit to EM and HAD Only E  = 5 GeV

17. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 17 GEM Relative Weighting EM HAD Relative Weight W = Slope EM / Slope HAD = 0.237 Slope HAD Slope EM

18. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 18 GEM Live Energy before and after Weight factor Before After ( Pion Energy)/Event (GeV) # of Pions Live Energy/Event for 50 GeV Pion in Mokka GEM

19. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 19 Mean Live Vs Incident Energy C TDR = 0.038 C GEM = 0.024 E = C * E Live

20. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 20 GEM Measured Energies for 100 GeV Pion Limited fit range to 3  for resolution Complete fit range for data

21. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 21 GEM and TESLA TDR Single Pion Resolution Still about 10% worse than what French colleagues achieved  Due to fitting of measured energy distributions TESLA-TDR GEM

22. 1/9/2003 UTA-GEM Simulation Report Venkatesh Kaushik 22 Conclusions UTA team has made a significant progress –Double GEM prototype (see A. White’s talk) functional UTA Developed software packages have been handed-over to N. Graf –Pandora-Pythia ASCII HEPEVT output generator interface –Mokka reader –Mokka ROOT analysis –Mokka to JAS GEM Simulation effort making good progress –Geometry implementation completed Test for simple and detailed geometry shows consistency –Single pion study of GEM response needed a method to obtain relative gain factor for EM and HAD normalization –Single pion response seems to be consistent with TDR –First glance at resolution seems to be comparable to TDR –Digital study in progress Eflow work will come next