UTA GEM DHCAL Simulation Jae Yu UTA Do

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

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 Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 2

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 (18 mm SS + 6. 5 mm GEM, 1 cmx 1 cm cells) • Single Pions used for performance & EFA studies – 5 – 100 Ge. V single pions – Analyzed them using ROOT Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 3

TESLA TDR Geometry Ecal – Electromagnetic Calorimeter Material: W/G 10/Si/G 10 plates (in yellow) • 1 mm W absorber plates • 0. 5 mm thick Si, embeded 2 G 10 plates of 0. 8 mm each Hcal – Hadronic Calorimeter Material: • 18 mm of Fe • 6. 5 mm of Polystyrene scintillator (in green) Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 4

UTA Double GEM Geometry Ar. CO Simple GEM Detailed GEM 2 0. 00 6. 5 mm 51 Cu . 0. 0 00 5 Kapton G 10 3. 4 mm Ar. CO 2 3. 1 mm GEM Detailed GEM Simple GEM 75 Ge. V p <E>=0. 81 0. 008 Me. V <E>=0. 80 0. 007 Me. V 25. 2 sec/event for Simple GEM v/s 43. 7 sec/event for Detailed GEM Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 5

Energy Deposit for 10 Ge. V Pions (GEM) f. EM>=0. 85 f. HC>=0. 85 Total Remainin g Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 6

GEM-Digital: Elive vs # of hits for π - Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 7

GEM Cell Occupancies ~85% single hit ~74% single hit ~15% >1 hit ~26% >1 hit Number of cells with higher number of hits increase w/ E Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 8

Energy Deposit/Ncells vs Layers for 50 Ge. V Pions E vs Layer Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 9

Extraction of of d. E/d. N Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 10

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 Sg. EHAD (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 Nov. 13, 2003 Status of DHCAL 11 Simulation, J. Yu

GEM – Relative Weights Analog Digital Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 12

GEM-Digital: Live Energy 50 Ge. V π- Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 13

GEM – Normalized Response Analog: 2. 4% Digital: 2. 6% Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 14

Converted energy: 50 Ge. V πAnalog Fits are Landau + Gaussian Nov. 13, 2003 Status of DHCAL Simulation, J. Yu Digital 15

Resolutions Analog GEM Digital GEM Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 16

EF Technique C 1 Normal Calorimetric Method: C 2 C 4 C 3 C 6 C 5 C 7 Energy Flow Method: p 2 p 3 p 5 p 7 Only susceptible part to Shower statistical fluctuation Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 17

Energy Flow Studies Using π • Charged particle energy subtraction based on trackcluster association is important to EFA • The algorithm must work well with single particle case • Pions E π- = 7. 5 Ge. V 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 Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 18

Calorimeter Centroid Determination • Energy Weighted Method • Hit Weighted Method • Density Weighted Method Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 19

Event Displays 6 jets Single E =50 Ge. V Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 20

Number of charged and Neutral particles <N>~6 <N>~12 Charged: e , , K Nov. 13, 2003 Neutral particles Status of DHCAL Simulation, J. Yu 21

R of all the particles relative to quark R flattens out after 0. 3 Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 22

h (E weighted vs Numerical Mean) E = 50 Ge. V 1 cm x 1 cm cells E weighted < h>=-3. 1 x 10 -5 s=1. 1 x 10 -2 Analog seems to be better than digital but not by significant factor Nov. 13, 2003 Numerical Mean < h>=-1. 2 x 10 -3 s=2. 5 x 10 -2 Status of DHCAL Simulation, J. Yu 23

- 7. 5 Ge. V π Bug? ? ? Energy Weighted Hit Density Weighted Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 24

Summary • Made a marked progress thanks to the LCRD and ADR support • Completed single 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 Nov. 13, 2003 Status of DHCAL 25 request Simulation, J. Yu

• EFA studies in progress – Study track – cluster association and energy subtraction usingle 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 Nov. 13, 2003 Status of DHCAL Simulation, J. Yu 26