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GEM DHCAL Simulation Studies

GEM DHCAL Simulation Studies. Introduction Analog Studies: TDR vs GEM Preliminary GEM Digital Studies Initial EFA studies with GEM Summary. J. Yu* Univ. of Texas at Arlington ALCW, July 15, 2003 Cornell University.

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GEM DHCAL Simulation Studies

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  1. GEM DHCAL Simulation Studies • Introduction • Analog Studies: TDR vs GEM • Preliminary GEM Digital Studies • Initial EFA studies with GEM • Summary J. Yu* Univ. of Texas at Arlington ALCW, July 15, 2003 Cornell University (*on behalf of the UTA team; S. Habib, V. Kaushik, J. Li, M. Sosebee, A. White)

  2. Introduction • DHCAL a solution for keeping the cost manageable for EFA • Finer cell sizes are needed for effective calorimeter cluster association with tracks and subsequent energy subtraction • UTA Has been working on DHCAL using GEM for • Flexible geometrical design, using printed circuit readout • Cell sizes can be as fine a readout as GEM tracking chamber!! • High gains, above 103~4,with spark probabilities per incident  less than 10-10 • Fast response • 40ns drift time for 3mm gap with ArCO2 • Relatively low HV • A few 100V per each GEM gap • Reasonable cost • Foils are basically copper-clad kapton • ~$400 for a specially prepared and framed 10cmx10cm foil Jae Yu: UTA GEM DHCAL ALCW, Cornell

  3. UTA GEM Simulation • Use Mokka as the primary tool • Kept the same detector dimensions as TESLA TDR • Replaced the HCAL scintillation counters with GEM (18mm SS + 6.5mm GEM, 1cmx1cm cells) • Single Pions used for initial studies • 3 – 100 GeV single pions • Analyzed them using ROOT • Compared the results to TDR analog as the benchmark • GEM Analog and Digital (w/ and w/o threshold) Jae Yu: UTA GEM DHCAL ALCW, Cornell

  4. Resolution curve – TESLA TDR I know this is about 10% higher than others. Estimate of 2.5% systematic uncertainties included Jae Yu: UTA GEM DHCAL ALCW, Cornell

  5. Double GEM schematic S.Bachmann et al. CERN-EP/2000-151 Jae Yu: UTA GEM DHCAL ALCW, Cornell

  6. Detailed GEM ArCO 2 0. 00 6.5mm 5 1 Cu Simple GEM . 0. 0 00 Kapton 5 G10 ArCO2 3.4 mm GEM 3.1 mm UTA Double GEM Geometry Jae Yu: UTA GEM DHCAL ALCW, Cornell

  7. Comparison of Detailed and Simple GEM Geometries Detailed GEM 75GeV p Simple GEM 75GeV p <E>=0.81  0.008MeV <E>=0.80  0.007MeV • 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 Jae Yu: UTA GEM DHCAL ALCW, Cornell

  8. Energy Deposit for 10 GeV Pions (GEM) fEM>=0.85 fHC>=0.85 Total Remaining Jae Yu: UTA GEM DHCAL ALCW, Cornell

  9. EM-HAD Relative Weighting Factor • To compensate the response differences between ECAL and GEM HCAL responses a procedure to normalize them had to be introduced • ELive=SEEM+ W SgEHAD(g:GEM Intrinsic gain) • 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* ELive Jae Yu: UTA GEM DHCAL ALCW, Cornell

  10. GEM TESLA TDR GEM Response (Analog) Estimate of 2.5% systematic uncertainties included Sampling fractions are as expected for both TDR and GEM Jae Yu: UTA GEM DHCAL ALCW, Cornell

  11. GEM TESLA TDR GEM Resolution (analog) Systematic uncertainties for GEM amplified by 50% to reflect unconsidered sources We just cannot make the resolution as good as our French colleagues saw. Jae Yu: UTA GEM DHCAL ALCW, Cornell

  12. GEM Digital Response Jae Yu: UTA GEM DHCAL ALCW, Cornell

  13. ~85% single hit ~74% single hit ~15% >1 hit ~26% >1 hit GEM Cell Occupancies Number of cells with higher number of hits increase w/ E Jae Yu: UTA GEM DHCAL ALCW, Cornell

  14. E vs Layer N vs Layer Energy Deposit/Ncells vs Layers for 50 GeV Pions Jae Yu: UTA GEM DHCAL ALCW, Cornell

  15. Extraction of of dE/dN Jae Yu: UTA GEM DHCAL ALCW, Cornell

  16. GEM Digital GEM Analog GEM Digital Response Estimate of 2.5% systematic uncertainties added to analog. Digital analysis w/ syst. in progress. Sampling fractions are consistent between digital and analog. Jae Yu: UTA GEM DHCAL ALCW, Cornell

  17. 95% efficiency Energy Deposit Efficiency MIP Efficiency At 0.23MeV Energy Deposited (MeV) GEM MIP Digital Threshold Efficiency Jae Yu: UTA GEM DHCAL ALCW, Cornell

  18. Discharge Study: NPairs for Muons in GEM Jae Yu: UTA GEM DHCAL ALCW, Cornell

  19. Single GEM gain/discharge probability • Single pion study almost completed • Understand average total charge deposit in a cell of various sizes • Study fake signal from spiraling charged particle in the gap A.Bressan et al, NIM A424, 321 (1998) Jae Yu: UTA GEM DHCAL ALCW, Cornell

  20. Ep=50 GeV Single Pion EFA Study • Track-cluster association is the first step for a good EFA • Must work for simplest cases • Start with single pion in analog and digital cases • Fit the centroid of shower using energy weighted (analog) and numerically averaged (digital) center in each layer • Measure the distance between fit shower position and the particle incident position Jae Yu: UTA GEM DHCAL ALCW, Cornell

  21. E weighted <Dh>=-3.1x10-5 s=1.1x10-2 Numerical Mean <Dh>=-1.2x10-3 s=2.5x10-2 Dh (E weighted vs Numerical Mean) Ep = 50 GeV 1cm x 1 cm cells Analog seems to be better than digital but not by significant factor Jae Yu: UTA GEM DHCAL ALCW, Cornell

  22. Summary • UTA’s GEM based DHCAL simulation has made significant progress in the past year • First pass single particle studies completed with a M.S. thesis, using Mokka: • GEM analog resolution comparable to TDR • GEM digital seems to be comparable to GEM analog • GEM digital with threshold will complete soon • Fit method refinement in progress • EFA studies began • Single particle study seems to show reasonable performance in E weighted vs numerical means • Jet final state studies will come next • Funding for ½ student for this effort available Jae Yu: UTA GEM DHCAL ALCW, Cornell

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