TEMPLATE DESIGN © CONFIG. 1: 12mm(Drift) / 12mm(T1) / 12mm(T2) / 12mm(Induction) CMS Endcap Resistive Plate Chamber Muon System Data Analysis Results Use Micro-Pattern Gas Detectors for CMS Muon Endcap System ? CERN SPS H4 Beamline 10x10 cm 2 Triple-GEM Prototypes First CMS Size GEM Prototype Characterization of Micro-Pattern Gas Detectors for Application in the CMS Muon Detection System D. Abbaneo 1, S. Bally 1, H. Postema 1, A. Conde Garcia 1, J.-P. Chatelain 1, G. Faber 1, L. Ropelewski 1, E. David 1, S. Duarte Pinto 1, G. Croci 1, M. Alfonsi 1, M. van Stenis 1, A. Sharma1, S. Bianco 2, S. Colafranceschi 2, L. Benussi 2, F. Fabbri 2, G. Saviano 2, N. Turini 3, E. Oliveri 3, G. Magazzu 3, A. Marinov 4, M. Tytgat 4 *, N. Zaganidis 4, M. Hohlmann 5, K. Gnanvo 5, Y. Ban 6, H. Teng 6, J. Cai 6 1 CERN, Geneva, Switzerland 2 LNF Frascati, Frascati, Italy 3 Universita' Degli Studi di Siena - INFN Sezione di Pisa, Pisa, Italy 4 Dept. of Physics and Astronomy, University of Gent, Gent, Belgium 5 Dept. of Physics and Space Sciences, Florida Institute of Technology, Melbourne, Florida, USA 6 Peking University, Beijing, China * presenter of this contribution  At present RPC endcap system limited to |η|<1.6  RPC Endcap completion phase 1, RE4/2-3, in 2012  Need other technology for RE1-4/1 region to sustain high LHC/SLHC rates of several kHz/cm 2 ! Staged η = 2.4 Micro Pattern Gas Detectors :  Spatial resolution ~ 100  m (  track < 45°)  Time resolution ~ 4-5 ns  Efficiency > 98%  Rate capability ~10 4 /mm 2  Non-flammable mixtures (like Ar-CO 2 )  Good gain stability for high particle fluxes  No ageing effects seen for high doses  Improve contribution to CMS Muon Trigger Efficiency  Combine triggering and tracking functions ?  Instrument the vacant (RE1-4/1) zones in forward CMS endcap region, 1.6 < |η |<2.4  Enhance and optimize the readout (η-φ) granularity by improved rate capability Honeycomb triple-GEM Single-mask triple-GEMStandard double-mask triple-GEM Endcap chambers are double-gap Bakelite RPCs with strip readout, operating in avalanche mode at 9.5kV with a C 2 H 2 F 4 - iC 4 H 10 -SF 6 ( ) gas mixture Drift Anode 3.00 mm GEM3 GEM2 GEM /2.00 mm 2.00 mm Drift gap T1 T2 Induction gap 1.00 /2.00 mm 2.15 mm Drift GEM3 Anode 3.25 mm GEM2 GEM mm Drift gap T1 T2 Induction gap Micromegas GEM ElectronsIons 60 % 40 % Induction gap e- e- e- e- I+I+ Multi-GEM Small prototypes were produced and tested at CERN in EN-ICE surface treatment workshop and RD51 lab :  Triple-GEM detectors with 10x10cm2 active area  GEM and cathode foils glued on fiberglass frames and mounted inside gas-tight box  Double/single mask GEMs  Different gap configuration for double mask GEM  Use of honeycomb spacers  Gain and discharge probability measurements  2 gap size configurations : 3/2/2/2 & 3/1/2/1 mm  Strip pitch = 0.8mm Use of honeycomb spacer frames in gaps could avoid the need for GEM foil stretching Different honeycomb structures (drift/T1/T2/induction) : Config 1 : 12 / 12 / 12 / 12 mm Config 2 : 6 / 12 / 12 / 12 mm Config 3 : 6 / 0 / 0 / 0 mm Use of single-mask technique to avoid alignment problems during etching of holes in top/bottom of GEM foils Prototypes were tested during several RD51 test beam campaigns in the CERN SPS H4 beamline with 150 GeV muons or pions  Gas flow ~5 l/h for different mixtures : Ar-CO 2 (70-30, 90-10) Ar-CO 2 -CF 4 ( , )  VFAT based readout from INFN Siena-Pisa  RD51 triple-GEM beam telescope used for tracking Beam direction Tracker GEM 3 Single-Mask / Honeycomb GEM Tracker GEM 2Tracker GEM 1 Standard GEM  First full-size triple-GEM prototype for CMS was produced and tested in SPS H4 beamline during October RD51 test beam campaign  Single-mask GEM technology  4x256 readout strips, 35 GEM HV sectors, 4 η partitions RD51 triple-GEM beam telescopeVFAT readout  3 Standard triple-GEM detectors with 10x10 cm 2 active area  Gas mixture Ar-C %  Strip pitch = 0.4 mm; 4x128 strips (2X-2Y)  VFAT readout  Always operated at a gain > 10 4  VFAT (TOTEM) is a digital on/off chip for tracking and triggering with an adjustable threshold for each of the 128 channels  Trigger function provides programmable “fast OR” information based on the region of the sensor hit  Output signals synchronous with 40MHz (25ns) clock ANALOG AND ASYNCHRONOUS DIGITAL AND SYNCHRONOUS IEEE Nuclear Science Symposium and Medical Imaging Conference, Oct. 30 – Nov. 6, 2010 – Knoxville, Tennessee Muon and pion beam profile Honeycomb GEM Performance  Different prototypes fully operational without major problems  Observed efficiency loss due to honeycomb spacers  Efficiencies :  Config 1 ~ 50%  Config 2 ~ 75%  Config 3 ~ 75% Prototypes demonstrated :  High efficiency and high gain  Good time resolution  Fast electronics  Single-mask GEM technology works well  Honeycomb GEM needs further tuning of efficiency General conclusions Standard GEM Performance Single-mask GEM Performance  Efficiency plateau at ~98%  Time resolution of 4ns obtained with 3/1/2/1 configuration and Ar-CO 2 -CF 4 ( )  Very high gain > 10 4 reachable  Single-mask GEM reaches similar performance level as standard GEM Resolution ~270μm compatible with 0.8mm strip pitch Efficiency ~98% 4ns time resolution obtained after correction for 25ns VFAT jitter VFAT threshold scan Tunable HV divider allowed Drift and Induction field scans Clear effect of gain, gas mixture and gap sizes on cluster size