TEMPLATE DESIGN © 2008

www.PosterPresentations.com

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

* Michael.Tytgat@cern.ch, 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