Aging Tests of of Full Scale CMS Cathode Strip Muon Chambers

Transcription

1 Aging Phenomena in Gaseous Detectors Aging Tests Full Scale CMS Cathode Strip Muon Chambers CMS Endcap Muon Collaboration Oleg Prokiev Fermilab, Batavia, IL, IL, USA USA Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200

2 Aging Test Goals Full Scale CMS ME/2 chamber from production line Large (2/3) chamber area irradiated, accumulated dose > LHC years Two rounds ageing tests: premixed gas, open loop gas system, volume/day (2000) closed loop gas system, 4 volume/day, 5% refresh gas (200) Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 2

3 Endcap Muon System CMS CMS Detector Detector Endcap Muon Chambers EMU EMU System System Parameters Parameters Cathode Strip Strip Chambers (largest (largest 3.4m 3.4m x.5m).5m) m 2 2 sensitive area area m 3 3 gas gas volume volume anode anode s s µm µm space space resolution ns ns bunch bunch crossing resolution Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 3

4 Chamber Design Trapezoidal Trapezoidal Six Six Cathode Cathode Strip Strip Chamber Chamber Chamber parameters: 50/200 50/200 µm µm anode/guard anode/guard diameter diameter mm mm spacing spacing mm mm gap gap (anode (anode cathode) cathode) 250/ /500 gr gr anode/guard anode/guard tension tension High High voltage voltage segmentation segmentation Gas Gas mixture: mixture: 40% 40% Ar Ar + 50%CO 50%CO 2 %CF %CF 4 Gas Gas gain gain > 5 5 High High Voltage Voltage kv kv Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 4

5 Chamber Materials, Components and Chemicals RTV Soldering Epoxy Epoxy Gluing Chamber material: Panels Panels FR4 FR4 sheets sheets + + polycarbonate polycarbonate core core Gap Gap bars, bars, anode anode bars, bars, spacers spacers FR4 FR4 Anode Anode s s LUMA LUMA gold gold plated plated tungsten tungsten Guard Guard s s gold gold plated plated CUBe CUBe guard guard RTV ORing Soldering Epoxy Chemicals: Chemicals: Components: Components: Capacitors Capacitors ceramic, ceramic, nf, nf, kv kv Resistors Resistors carbon carbon composite composite ORing ORing rubber rubber fluorocarbon fluorocarbon Epoxy Epoxy 226, 226, part part A and and B (contractual (contractual epoxy) epoxy) Epoxy Epoxy Epolite Epolite hardener hardener ( ( gluing) gluing) RTV RTV curing curing agent agent (outside (outside chamber chamber sealing) sealing) Solder Solder Almit Almit KR9 KR9 SH SH RMA RMA,, Seika Seika Corp. Corp. (new (new product) product) Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 5

6 Ageing Setup and Conditions Irradiated Area 52 cm A B C 75 cm GIF Area 85 cm Gas out Gas in # #6 Gamma Gamma Radiation Radiation Facility Facility (CERN): (CERN): Cs Cs (E (E γ =66 γ =66 kev), kev), GBq GBq Rate Rate in in the the chamber chamber 0 0 times times that that at at LHC LHC khz/cm khz/cm khz/cm khz/cm Radiation Radiation exposure exposure (for (for planes planes 2,3,4,5): 2,3,4,5): months months (40 (40 LHC LHC years) years) Irradiated Area C/cm C/cm 2 2,, or or C/cm C/cm (0.8 (0.8 C/cm C/cm per per LHC LHC years) years) Reference Reference Planes Planes (#, (#, #6) #6) HV HV is is f f during during irradiation irradiation Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 6

7 Aging Test at GIF Chamber Test ME/2 Chamber at GIF Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 7

8 Gas and Gas System Gas mixture (premixed) Ar/CO 2 /CF 4 40/50/ 2000 Gas mixture (premixed) Ar/CO 2 /CF 4 40/50/ 200 Purity components, % Ar 48 ( ) CO 2 48 ( ) CF 4 45 ( ) Gas System MOpen loop M Flow rate 3 l/h ( V/day) MGas pipes: 23 m copper tubes 3 m plastic tube (rilsan) Purity components, % 2 Ar CO CF Gas System M Closed loop M Flow rate nominal (2 l/h, or 4 V/day) M Fresh gas 5% nominal (0.6 l/h) M Gas pipes (copper): 50m input tube ( 2 mm) 50m input tube ( 6 mm) cleaned according to CERN spec. Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 8

9 Closed Loop Circulation Gas System Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 9

10 Monitored Chamber Parameters Anode Current during irradiation Anode GIF GIF rates Dark current Anode noise rates Strip tostrip capacitance Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200

11 Chamber Chamber Cathode Cathode Current Current Chamber Gas Gain Current, microampers Current, microampers High Voltage, kv High Voltage, kv Gas Gas g g ain ain March March,, April April 3,2000 3,2000 April April,, June June,, July July,, C/cm Gas Gas Gain Gain = 5 5 at at HV HV = kv kv Gas Gas gain gain stayed stayed constant constant HV, HV, kv kv Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200

12 Aging Test 200 Accumulated Charge Accumulated Accumulated Charge Charge per per cm cm anode anode ( ( Part Part A) A) Dose Dose [C/cm] [C/cm] LHC LHC years years = = C/cm C/cm 50 LHC years 50 LHC years 40 LHC years 40 LHC years 30 LHC years 30 LHC years 20 LHC years 20 LHC years LHC years LHC years, 6 reference Time Time [Days] [Days] Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 2

13 Gas Gain Aging Test 2000 Aging Test 200 Relative Relative currents currents i2*2.(i+i6) i2*2.(i+i6) i3*2./i+i6) i3*2./i+i6) i4*2.(i+i6) i4*2.(i+i6) i5*2.(i+i6) i5*2.(i+i6) Accumulated Accumulated charge charge per per cm cm Wire Wire (C/cm) (C/cm) Relative currents Relative currents Accumulated charge per cm Wire (C/cm) Accumulated charge per cm Wire (C/cm) Gas Gain remained unchanged Gas Gain remained unchanged Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 3

14 Dark Current Dark currents, na Dark currents, na Aging Aging Test Test I I2 I3 II4 I2I5 I3I6 I4 I5 I6 Dark Current, na Dark Current, na Aging Aging Test Test Accumulated charge per cm (C/cm) Accumulated charge per cm (C/cm) Accumulated Charge per cm (C/cm) Accumulated Charge per cm (C/cm) Dark current increased from na na to to typically na na per per plane Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 4

15 Dark Rates Average Average rates, rates, Hz Hz Aging Test 2000 Dark Dark rates rates Accumulated Accumulated charge charge per per cm cm (C/cm) (C/cm) Average rates, Hz Average rates, Hz Dark rates Dark rates Aging Test 200 # #2 # #3 #2 #4 #3 #5 #4 #6 #5 # Accumulated charge per cm (C/cm) Accumulated charge per cm (C/cm) Noise Noise count count remained unchanged for for both both runs runs in in and and Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 5

16 Strip to Strip Resistance Resistance, GOhm Resistance, GOhm Resistance, Resistance, GOhm GOhm Aging 2000 Test Aging Test Accumulated Charge per cm (C/cm) Accumulated Charge per cm (C/cm) Accumulated Accumulated Charge Charge per per cm cm (C/cm) (C/cm) Resistance Resistance between between Strips Strips Changed Changed from from 0 0 to to 0 0 GOhm GOhm during during irradiation irradiation Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 6

17 Cathode Plane Deposits Cathode planes: thin thin uniform uniform layer layer deposits: deposits: extends extends beyond beyond the the irradiated irradiated zone zone also, also, found found on on the the last last plane plane (along (along gas gas flow) flow) that that had had HV HV f f during during irradiation irradiation Composition Composition deposits: deposits: O, O, F, F, Si Si Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 7

18 Anode Wires Anode s: Wires Wires stayed stayed fairly fairly clean clean With With some some minor minor deposits, sporadically scattered Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 8

19 Summary Aging tests with with two two CMS Cathode Strip Chambers were performed In In one one the the two two tests a closed loop gas gas system was was used At At accumulated dose C/cm (30 ( LHC LHC years) no no significant changes in in chamber performance (dark current, noise count, gas gas gain, efficiency) were observed Striptostrip resistance decreased but but stayed well well within technical specification (> (>.0.0 MOhm) Accumulation deposits on on the the cathode planes was was observed while s stayed fairly clean All All test test showed that that CMS CSCs with with Ar/CO2/CF4 gas gas mixture could be be run run in in the the LHC LHC environment without appreciable aging effects Oleg Prokiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 200 9