UTA GEM DHCAL Simulation

UTA GEM DHCAL Simulation • Introduction • GEM Geometry Implementation • Single Pion Study for GEM performances • GEM Analog Mode • GEM Digital Mode • Single Pion EFA Studies • Summary Jae Yu* UTA DoE Site Visit Nov. 13, 2003 (*On behalf of the UTA team; A. Brandt, K. De, S. Habib, V. Kaushik, J. Li, M. Sosebee, A. White)

Introduction • LC physics topics require excellent jet energy and angular resolutions • Energy flow algorithm is one of the solutions • Large number of readout channel will drive up the cost for analogue style energy measurement  Digital HCAL • Tracking calorimeter with high gain sensitive gap • GEM is one such detector technology • Simulation effort to understand detector progressed along with prototype development • Thanks to the support from LCRD and ADR Status of DHCAL Simulation, J. Yu

UTA GEM Simulation • LC Physics Events: Pandora – Phythia • 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 performance & EFA studies • 5 – 100 GeV single pions • Analyzed them using ROOT Status of DHCAL Simulation, J. Yu

TESLA TDR Geometry • Ecal – Electromagnetic Calorimeter Material: W/G10/Si/G10 plates (in yellow) • 1mm W absorber plates • 0.5 mm thick Si, embeded 2 G10 plates of 0.8 mm each • Hcal – Hadronic Calorimeter • Material: • 18 mm of Fe • 6.5 mm of Polystyrene scintillator (in green) Status of DHCAL Simulation, J. Yu

UTA Double GEM Geometry Detailed GEM 75GeV p Simple GEM 75GeV p Detailed GEM <E>=0.81  0.008MeV <E>=0.80  0.007MeV 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 25.2sec/event for Simple GEM v/s 43.7 sec/event for Detailed GEM Status of DHCAL Simulation, J. Yu

Energy Deposit for 10 GeV Pions (GEM) fEM>=0.85 fHC>=0.85 Total Remaining Status of DHCAL Simulation, J. Yu

GEM-Digital: Elive vs # of hits for π- Status of DHCAL Simulation, J. Yu

~85% single hit ~15% >1 hit GEM Cell Occupancies ~74% single hit ~26% >1 hit Number of cells with higher number of hits increase w/ E Status of DHCAL Simulation, J. Yu

E vs Layer N vs Layer Energy Deposit/Ncells vs Layers for 50 GeV Pions Status of DHCAL Simulation, J. Yu

Extraction of of dE/dN Status of DHCAL Simulation, J. Yu

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 Status of DHCAL Simulation, J. Yu

GEM – Relative Weights Analog Digital Status of DHCAL Simulation, J. Yu

GEM-Digital: Live Energy 50 GeV π- Status of DHCAL Simulation, J. Yu

GEM – Normalized Response Analog: 2.4% Digital:2.6% Status of DHCAL Simulation, J. Yu

Converted energy: 50 GeV π- Analog Digital Fits are Landau + Gaussian Status of DHCAL Simulation, J. Yu

Digital GEM Analog GEM Resolutions Status of DHCAL Simulation, J. Yu

Only susceptible part to Shower statistical fluctuation EF Technique Normal Calorimetric Method: C1 C2 C3 C4 C6 C5 Energy Flow Method: C7 p3 p2 p5 p7 Status of DHCAL Simulation, J. Yu

Energy Flow Studies Using π- • Charged particle energy subtraction based on track-cluster association is important to EFA • The algorithm must work well with single particle case • Pions Eπ- = 7.5 GeV chosen for study • Studied the energy distribution of pions in jet events • Find the centroid of the shower ( HCAL ) using • Energy weighted method • Hits weighted method • Density weighted method • Match the extrapolated centroid with TPC last layer hit to get Δ and Δφ distribution Status of DHCAL Simulation, J. Yu

Calorimeter Centroid Determination • Energy Weighted Method • Hit Weighted Method • Density Weighted Method Status of DHCAL Simulation, J. Yu

Ep=50 GeV Event Displays 6 jets Single p Status of DHCAL Simulation, J. Yu

Number of charged and Neutral particles <N>~6 <N>~12 Charged: e, , K Neutral particles Status of DHCAL Simulation, J. Yu

R flattens out after 0.3 R of all the particles relative to quark Status of DHCAL Simulation, J. Yu

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 Status of DHCAL Simulation, J. Yu

Bug???  - 7.5 GeV π- Energy Weighted Hit Density Weighted Status of DHCAL Simulation, J. Yu

Summary • Made a marked progress thanks to the LCRD and ADR support • Completed single p GEM DHCAL performance studies • Initial study documented in Habib’s MS thesis • More detailed and refined study being completed by Kaushik • Analog resolution seems to be worse compared to other detector technology due to large fluctuation in initial ionization electrons • Digital, however, performance is comparable to other analog technologies • Released our Pandora – Phythia ASCII and other analysis packages to LC software group per their request Status of DHCAL Simulation, J. Yu

EFA studies in progress • Study track – cluster association and energy subtraction using single pion  Three methods being investigated • Study typical distance between charged particles within the jet • Determine necessary resolving power for realistic situation • Prepare for larger scale prototype, cosmic ray stack and TB simulation • Development of analysis software • Continued and increased support is critical to make the next quantum jump Status of DHCAL Simulation, J. Yu

UTA GEM DHCAL Simulation