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UTA GEM DHCAL SIM. Introduction Digital Hadron Calorimeter Requirements GEM in the sensitive gap UTA GEM DHCAL Prototype Status Simulation Status Summary. J. Yu* Univ. of Texas at Arlington Nov. 7 - 9, 2002 NIU/NICADD.
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UTA GEM DHCAL SIM • Introduction • Digital Hadron Calorimeter Requirements • GEM in the sensitive gap • UTA GEM DHCAL Prototype Status • Simulation Status • Summary J. Yu* Univ. of Texas at Arlington Nov. 7 - 9, 2002 NIU/NICADD (*On behalf of the UTA team; A. Brandt, K. De, S. Habib, V. Kaushik, J. Li, M. Sosebee, A. White)
Introduction • LC physics topics • 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 Jae Yu: GEM Based DHCAL
Goals for UTA DHCAL Development • Develop digital hadron calorimetry for use with EFA • Aim for cost effectiveness and high granularity • Look for a good tracking device for the sensitive gap • Develop GEM cell(s) and prototype • Develop module/stack design for EFA optimization • Simulate GEM behavior in calorimeter • Implement GEM readout structure into simulation • Develop EF and calorimeter tracking algorithms • Cost effective, large scale GEM DHCAL Jae Yu: GEM Based DHCAL
Why GEM? • GEM developed by F. Sauli (CERN) for use as pre-amplification stage for MSGC’s • Allow flexible and geometrical design, using printed circuit readout Can be as fine a readout as GEM tracking chamber!! • High gains, above 104,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 compared to 10-16kV for RPC • Rather reasonable cost • Foils are basically copper-clad kapton • ~$400 for a specially prepared and framed 10cmx10cm foil Jae Yu: GEM Based DHCAL
Large amplification 140mm 70mm CERN-open-2000-344, A. Sharma Jae Yu: GEM Based DHCAL
GEM gains High gain Low voltage differential!! CERN GDD group Jae Yu: GEM Based DHCAL
Double GEM DHCAL Design Anode pad Embeded onboard readout Ground Thr. Thr. AMP DISC AMP DISC REG REG Ground to avoid cross-talk Digital/serial output Preliminary readout design Jae Yu: GEM Based DHCAL
Double GEM test chamber • Sufficient space for foil manipulation • Readout feed-through, retaining large space for ease of connection • Clear cover to allow easy monitoring • Readout pads connection at the top 2cmx2cm pad design J. Li, UTA Jae Yu: GEM Based DHCAL
UTA GEM Test Chamber HV layout Drift gap HV fed from one supply but individually adjusted Good to prevent HV damage on the foils 2.1kV Transfer gap Induction gap Jae Yu: GEM Based DHCAL
UTA GEM Prototype Status • Readout circuit board (2cmx2cm pads) constructed • HV Connection implemented • Two GEM foils in the UTA Nano fabrication facility cleanroom • Preamp in hand and characterization completed (LeCroy HQV800) Amplification factor of 300 for 5xGEM size signal (LeCroy HQV800 ) Jae Yu: GEM Based DHCAL
Want to know how GEM Foils look like? Jae Yu: GEM Based DHCAL
Single GEM gain/discharge probability • Simulation study in progress using single pions before multi-jets • Determine Maximum total charge deposit in a cell of various sizes and gains • Study fake signal from spiraling charged particle in the gap A.Bressan et al, NIM A424, 321 (1998) Jae Yu: GEM Based DHCAL
UTA Simulation Status • Two masters students have been working on this project • Pandora-Phythia implementation and HEPEvt ASCII output in place • Mokka successfully installed • Mokka Geometry database downloaded and installed at UTA • Completed single pion studies using default geometry • Reproduced expected response • Energy resolution seems to be reasonable also • Preliminary mixture GEM geometry implemented • Single pion study with mixture GEM begun • Root macro and JAS based analysis packages developed • Proceed with more detailed GEM geometry implementation Jae Yu: GEM Based DHCAL
Single Pion Studies w/ Default TESLA Geometry • Single pion events using Mokka particle gun command. • Incident energy range: 5 – 200GeV • kinematics information on primary particles in the files • Developed an analysis program to read total energies deposited per pion for each incident energy. • Mean Energy vs Incident pion energies • Energy conversion from the slope of the straight line • Conversion factor is 3.47% and agrees with the computed sampling fraction Jae Yu: GEM Based DHCAL
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) Jae Yu: GEM Based DHCAL
TESLA TDR detector live energy deposit for single pions Jae Yu: GEM Based DHCAL
TESLA TDR Elive vs Ep % Jae Yu: GEM Based DHCAL
TESLA TDR CAL Single Pion Resolution Jae Yu: GEM Based DHCAL
GEM Simulation Status • Mokka Geometry database downloaded and installed at UTA • New Geometry driver written Mixture GEM geometry implemented Need to use ArCO2 only • Single pion study begun for discharge probability • Initial study shows that the number of electron, ion pair with gain of 104 will be on the order of 107 for single 200GeV pions • Getting pretty close to the 108 from other studies Might get worse for jets from W pairs, due to fluctuation • Need more studies to compute the discharge probability. • Cell energy deposit being investigated to determine optimal threshold based on cell energy Proceed to energy resolution studies • Determine optimal gain using live energy deposit vs incident energy Jae Yu: GEM Based DHCAL
GEM Prototype Geometry Jae Yu: GEM Based DHCAL
Venkat, TSAPS Meet Oct 10 - 12, 2002 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 Jae Yu: GEM Based DHCAL
Single Pion Cell Energy Deposit in GEM HCal Jae Yu: GEM Based DHCAL
Single pion Energy with GEM 50GeV p ELive 15GeV p EMeas 10.6MeV Jae Yu: GEM Based DHCAL
GEM Sampling Weight Sampling: 2~4x10-3 Statistics too low to produce reliable gaussian fit This depends heavily on EM section without proper GEM gain factor taken into account. Jae Yu: GEM Based DHCAL
Summary • Hardware prototype making significant progress • GEM foils delivered and are in the clean room for safe keeping • Preamp and Discriminator in hands Preamp characterized • HV System implemented • Readout Pad implemented • Almost ready to put GEM foils in the prototype box • GEM foil mass production being looked into by 3M in Austin, Texas • Simulation effort made a marked progress • Single pion study of Mokka default TESLA TDR geometry complete • Analysis tools in place and seem to work well • The resolution seems to be reasonable • Preliminary GEM Mixture geometry implemented • Need to redo the response study with gain factored in… • Initial estimate of e+Ion pair seems to be at about 107 for 200GeV pions • Local Geometry database implemented • Optimal threshold for digitization and gain factor will come soon • Will soon move onto realistic events, WW, ZZ, or t`t jets • Still ways to go before effective EFA and TRKA studies Jae Yu: GEM Based DHCAL