config. 1: 12mm (drift) / 12 mm (t1) / 12 mm (t2) / 12 mm (induction)
DESCRIPTION
Characterization of Micro-Pattern Gas Detectors for Application in the CMS Muon Detection System. Ions. I +. e -. 40 %. Induction gap. e -. 60 %. Electrons. η = 2.4. Staged. Drift. 3.00 mm. Drift gap. GEM3. 1.00 /2.00 mm. T1. GEM2. 2.00 mm. T2. GEM1. 1.00 /2.00 mm. - PowerPoint PPT PresentationTRANSCRIPT
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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 ?
Measurements @ CERN SPS H4 Beamline
10x10 cm2 Triple-GEM Prototypes
First CMS Size GEM Prototype
Characterization of Micro-Pattern Gas Detectors for Application in the CMS Muon Detection System
D. Abbaneo1, S. Bally1, H. Postema1, A. Conde Garcia1, J.-P. Chatelain1, G. Faber1, L. Ropelewski1, E. David1, S. Duarte Pinto1, G. Croci1, M. Alfonsi1, M. van Stenis1, A. Sharma1, S. Bianco2, S. Colafranceschi2, L. Benussi2, F. Fabbri2, G. Saviano2, N. Turini3, E. Oliveri3, G. Magazzu3, A. Marinov4, M. Tytgat4*, N. Zaganidis4, M. Hohlmann5, K. Gnanvo5, Y. Ban6, H. Teng6, J. Cai6
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
* [email protected], 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/cm2!
RE1/1
RE1/2
RE1/3
RE2/1
RE2/2
RE2/3
RE3/1
RE3/2
RE3/3
RE4/1
RE4/2
RE4/3
No. of chambers 36*2 36*2 36*2 18*2 36*2 36*2 18*2 36*2 36*2 18*2 36*2 36*2
Staged η = 2.4
Micro Pattern Gas Detectors : Spatial resolution ~ 100 m (track< 45°) Time resolution ~ 4-5 ns Efficiency > 98% Rate capability ~104/mm2
Non-flammable mixtures (like Ar-CO2) 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-GEMSingle-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 C2H2F4-iC4H10-SF6 (96.2-3.5-0.3) gas mixture
Drift
Anode
3.00 mmGEM3GEM2
GEM1
1.00 /2.00 mm2.00 mm
Drift gap
T1T2
Induction gap 1.00 /2.00 mm
2.15 mm
Drift
GEM3
Anode
3.25 mm
GEM2GEM1
2.215 mm2.215 mm
Drift gap
T1T2
Induction gap
Micromegas
GEM
ElectronsElectrons
IonsIons
60 %
40 %Induction gap
e-
e-
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 mmConfig 2 : 6 / 12 / 12 / 12 mmConfig 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-CO2 (70-30, 90-10)Ar-CO2-CF4 (45-15-40, 60-20-20)
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 2 Tracker GEM 1
Standard GEM
First full-size triple-GEM prototype for CMS was produced and tested in SPS H4 beamline during October 18-28 RD51 test beam campaign
Single-mask GEM technology
4x256 readout strips, 35 GEM HV sectors, 4 η partitions
RD51 triple-GEM beam telescope VFAT readout 3 Standard triple-GEM detectors with 10x10 cm2 active area Gas mixture Ar-C02 70-30% Strip pitch = 0.4 mm; 4x128 strips (2X-2Y) VFAT readout Always operated at a gain > 104
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-CO2-CF4 (45-15-40) Very high gain > 104 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