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Digital Hadron Calorimetry for the Linear Collider Using Gas Electron Multiplier Technology. Andy White U.Texas at Arlington (for J.Yu, C.Han, J.Li, D.Jenkins, J.Smith, K.Parmer, A.Nozawa, V.Kaushik) 12/7/04 CALICE/DESY. Items. GEM/DHCAL definition Signal studies/crosstalk
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Digital Hadron Calorimetry for the Linear Collider Using Gas Electron Multiplier Technology Andy White U.Texas at Arlington (for J.Yu, C.Han, J.Li, D.Jenkins, J.Smith, K.Parmer, A.Nozawa, V.Kaushik) 12/7/04 CALICE/DESY
Items • GEM/DHCAL definition • Signal studies/crosstalk • Localized source studies • GEM simulation • Next steps for prototyping • GEM foil design + production • Readout electronics • Test Beam
Double GEM schematic Create ionization Multiplication Signal induction From S.Bachmann et al. CERN-EP/2000-151
Ar:CO2=70:30 Double-GEM prototype results: Gas mix
Crosstalk studies Large Gap Small Gap Usual situation little xtalk
Localized source studies Used various forms of collimation with beta source. Studied center of pad vs. edge etc. Precursor to fully localized single track studies.
Sr-90 D=1" Source disk size
Sr-90 D=1" Steel bars
On the Edges of two pads(~2mm.) Scintillator-trig, dV=400v, Sr-90, Ar:Co2=85:15
Sr-90 D=1" Collimator
Scintillator-trig, dV=400v, Sr-90, Ar:Co2=85:15 j=10 mm.(h=10mm.)
Sr-90 D=1" More collimation
No source, cosmic veto Scin-trig + C-ray VETO dV=381v, Sr-90, Ar:Co2=85:15 j=10 mm.(h=10mm.)
GEM Simulation Need to model the processes of ionization, drifting, multiplication, transfer, and signal collection. -> Signal size -> Signal shape – input to SPICE model -> Physical spread of signal on pads -> Effects of E B in calorimeter -> Time response of double GEM
Next steps for prototyping • Determined by availability of GEM foils of larger size. • Likely short-term availability is for 305mmx305mm foils from 3M Corporation. • Plan is to build a cosmic (vertical) stack of 5-6 layers using the 305mmx305mm foils. • Use Fermilab 32-channel cards until ASIC available. • Restrict readout to 10x10 channels/layer while using the Fermilab cards.
Cosmic stack using Double GEM counters Fermilab beam chamber DGEM DGEM DGEM DGEM DGEM Fermilab beam chamber
305mm x 305mm layer Trace edge connector -> Fermilab 32 ch board (10 x 10) – 4 active area
Cosmic stack using Double GEM counters • Single cosmic tracks. • Hit multiplicity (vs. simulation) • Signal sharing between pads (e.g. vs. angle) • Efficiencies of single DGEM counters • Effects of layer separators • Operational experience with ~500 channel system • Possible test-bed for ASIC when available – rebuild one or more DGEM chambers.
T2K large GEM foil design (Close to COMPASS(CERN) foil design)
T2K large GEM foil design • Institutes cooperating on foil production: • U. Victoria BC (Canada) (T2K and LC TPC) • U. Washington (DHCAL) • Louisiana Tech. U. (LC TPC) • Tsinghua U. (DHCAL) • IHEP Beijing (GEM development) • U. Texas Arlington (DHCAL) • (share cost of masks, economy of scale in foil production)
140mm 70mm GEM foil/operation GEM field and multiplication From CERN-open-2000-344, A. Sharma Invented by Fabio Sauli/CERN
Development of large-scale GEM layer for final test beam stack ~1m Test beam stack will be 1m3, with 40 active layers each ~8mm thick between steel absorber plates. 305mm GEM strip from 3M roll
Development of GEM sensitive layer Absorber strong back Gas inlet/outlet (example) Cathode layer 3 mm Non-porous, double-sided adhesive strips 1 mm 1 mm 9-layer readout pc-board Anode(pad) layer Fishing-line spacer schematic (NOT TO SCALE) GEM foils
Readout Electronics • Working with ANL/RPC Group on common front-end readout ASIC: • Selectable gain: high for GEM, low for RPC. • Circuit evaluation using SPICE at UTA – in process • Common PC board/anode pad layer with RPC • Digital design ~complete, Analog design following BTeV chip. DHCAL specific final development in early 2005.
Test Beam (details are subject of separate presentation) 1m3 stack 40 layers, steel absorber, (shared with RPC group) GEM active gaps,
Test Beam - funding • LCRD/UCLC funding (US) so far limited to ~$700K/year • - too little to support assembly of test beam modules and associated electronics. • Alternative funding: treat LC test beam as project, target NSF-MRI program. Proposals due January 27. Workshop at UTA, December 13-14 to write! • Funds for SiD ECal, Scint-HCal, GEM-HCal, RPC-HCal, Muon-Tail Catcher at total level of ~$1M.
Personnel New collaborators on GEM/DHCAL: - University of Washington, T. Zhou - Tsinghua University, Beijing, China - IHEP, Beijing
Conclusions • Progress in signal studies, including local effects around pad boundaries • Beginning GEM electromagnetic simulations • Next prototype will be a cosmic stack of 5-6 double GEM layers • Joint development of GEM foils with other groups • Starting SPICE simulation of analog readout electronics • Preparing Test Beam funding request