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Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 1
Aging Phenomena in Gaseous Detectors
Aging Tests of Full ScaleCMS Cathode Strip Muon Chambers
CMS Endcap Muon Collaboration
Oleg Prokofiev Fermilab, Batavia, IL, USA
Aging Tests of Full ScaleAging Tests of Full ScaleCMS Cathode StripCMS Cathode Strip Muon Muon Chambers Chambers
CMS Endcap Muon Collaboration
OlegOleg Prokofiev Prokofiev Fermilab, Batavia, IL, USA
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 2
Aging Test Goals
• Full Scale CMS ME1/2 chamber from production line• Large (2/3) chamber area irradiated,
accumulated dose > 30 LHC years• Two rounds of ageing tests:
premixed gas, open loop gas system, 1 volume/day (2000)
closed loop gas system, 4 volume/day, 5% refresh gas (2001)
• Full Scale CMS ME1/2 chamber from production line• Large (2/3) chamber area irradiated,
accumulated dose > 30 LHC years• Two rounds of ageing tests:
premixed gas, open loop gas system, 1 volume/day (2000)
closed loop gas system, 4 volume/day, 5% refresh gas (2001)
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 3
Endcap Muon System
Endcap Muon Chambers
CMS DetectorCMS DetectorCMS Detector
• 540 Cathode Strip Chambers(largest 3.4m x 1.5m)
• 6000 m2 sensitive area
• 65 m3 gas volume
• 2 500 000 anode wires
• 150 µµµµm space resolution
• 25 ns bunch crossing resolution
• 540 Cathode Strip Chambers(largest 3.4m x 1.5m)
• 6000 m2 sensitive area
• 65 m3 gas volume
• 2 500 000 anode wires
• 150 µµµµm space resolution
• 25 ns bunch crossing resolution
EMU System ParametersEMU System ParametersEMU System Parameters
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 4
Chamber Design
Trapezoidal Six LayerCathode Strip ChamberTrapezoidal Six LayerTrapezoidal Six Layer
Cathode Strip ChamberCathode Strip ChamberChamber parameters:• 50/200 µµµµm anode/guard wire diameter
• 3.12 mm wire spacing
• 4.75 mm gap (anode – cathode)
• 250/500 gr anode/guard wire tension
• High voltage segmentation
Chamber parameters:• 50/200 µµµµm anode/guard wire diameter
• 3.12 mm wire spacing
• 4.75 mm gap (anode – cathode)
• 250/500 gr anode/guard wire tension
• High voltage segmentation
Gas mixture: 40% Ar + 50%CO2 + 10%CF4
Gas gain > 105
High Voltage – 3.7 kV
Gas mixture: 40% Ar + 50%CO2 + 10%CF4
Gas gain > 105
High Voltage – 3.7 kV
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 5
Chamber Materials, Components and Chemicals
RTV
O-Ring
RTV
Chamber material: Panels - FR-4 sheets + polycarbonate core Gap bars, anode bars, spacers - FR-4 Anode wires - LUMA gold plated tungsten Guard wires - gold plated CU-Be guard
Chamber material: Panels - FR-4 sheets + polycarbonate core Gap bars, anode bars, spacers - FR-4 Anode wires - LUMA gold plated tungsten Guard wires - gold plated CU-Be guard
Components: Capacitors - ceramic, 1nF, 7.5 kV Resistors - carbon composite O-Ring – rubber fluorocarbon
Components: Capacitors - ceramic, 1nF, 7.5 kV Resistors - carbon composite O-Ring – rubber fluorocarbon
Chemicals: Epoxy - 2216, part A and B (contractual epoxy) Epoxy – Epolite 5313 + hardener (wire gluing) RTV - 41 + curing agent (outside chamber sealing) Solder wire Almit KR-19 SH RMA , Seika Corp. (new product)
Chemicals: Epoxy - 2216, part A and B (contractual epoxy) Epoxy – Epolite 5313 + hardener (wire gluing) RTV - 41 + curing agent (outside chamber sealing) Solder wire Almit KR-19 SH RMA , Seika Corp. (new product)
Epoxy
Soldering
Epoxy
Soldering
EpoxyGluing
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 6
Irradiated Area
GIF Area
Gamma Radiation Facility (CERN):137Cs (Eγγγγ=661 keV), 740 GBq
Rate in the chamber• ~ 100 times of that at LHC
• ~ 15-20 kHz/cm2
• ~ 5 kHz/cm of wire
Radiation exposure (for planes 2,3,4,5):• ~ 3 - 5 months (~40 LHC years)
• ~ 1 C/cm2 , or ~ 0.3 C/cm of wire
(0.8 C/cm per 10 LHC years)
• Reference Planes (#1, #6) HV is off
during irradiation
Gamma Radiation Facility (CERN):137Cs (Eγγγγ=661 keV), 740 GBq
Rate in the chamber• ~ 100 times of that at LHC
• ~ 15-20 kHz/cm2
• ~ 5 kHz/cm of wire
Radiation exposure (for planes 2,3,4,5):• ~ 3 - 5 months (~40 LHC years)
• ~ 1 C/cm2 , or ~ 0.3 C/cm of wire
(0.8 C/cm per 10 LHC years)
• Reference Planes (#1, #6) HV is off
during irradiation
175 cm
85 c
m
52 c
m A B C
Ageing Setup and Conditions
Gas in
Gas out
#1#6
Irradiated Area
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 7
Aging Test at GIF
ME1/2 Chamber at GIFChamber Test
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 8
Gas and Gas System
2000• Gas mixture (premixed)
Ar/CO2/CF4 - 40/50/10
• Purity of components, % 1 2
Ar 99.998 99.996CO2 99.998 99.990CF4 99.995 99.995
• Gas System� Closed loop� Flow rate nominal (12 l/h, or 4 V/day)� Fresh gas 5% of nominal (0.6 l/h)� Gas pipes (copper):
• 50m input tube ( 12 mm)• 50m input tube ( 16 mm)• cleaned according to CERN spec.
2001• Gas mixture (premixed)
Ar/CO2/CF4 - 40/50/10
• Purity of components, % Ar - 48 ( 99.998) CO2 - 48 ( 99.998) CF4 - 45 ( 99.995)
• Gas System�Open loop� Flow rate 3 l/h (1 V/day)
�Gas pipes:• 23 m of copper tubes• 13 m of plastic tube (rilsan)
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 9
Closed Loop Circulation Gas System
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 10
Monitored Chamber Parameters
� Anode Current during irradiation
� Anode GIF rates
� Dark current
� Anode noise rates
� Strip- to-strip capacitance
� Anode Current during irradiation
� Anode GIF rates
� Dark current
� Anode noise rates
� Strip- to-strip capacitance
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 11
Chamber Gas Gain
Gas gain stayed constantGas gain stayed constant
Gas Gain = 105
at HV = 3.7 kVGas Gain = 105
at HV = 3.7 kV
Chamber Cathode Current
0.0001
0.001
0.01
0.1
1
10
100
1000
0 1 2 3 4High Voltage, kV
Cur
rent
, mic
roA
mpe
rs
Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6
Chamber Cathode Current
0.0001
0.001
0.01
0.1
1
10
100
1000
0 1 2 3 4High Voltage, kV
Cur
rent
, mic
roA
mpe
rs
Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6
1000
10000
100000
1000000
2.6 2.8 3 3.2 3.4 3.6 3.8 4
HV, kV
Gas
gai
n
March 11, 2000
April 3,2000
April 10, 2000
June 10, 2000
July 1, 2000
1000
10000
100000
1000000
2.6 2.8 3 3.2 3.4 3.6 3.8 4
HV, kV
Gas
gai
n
March 11, 2000
April 3,2000
April 10, 2000
June 10, 2000
July 1, 2000
0.3
C/c
m
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 12
Aging Test 2001 Accumulated Charge
Accumulated Charge per cm of anode wire ( Part A)
0
0.1
0.2
0.3
0.4
0.5
0 20 40 60 80 100 120 140 160 180
Time [Days]
Dose
[C/c
m]
Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6
10 LHC years = 0.08 C/cm
30 LHC years
20 LHC years
10 LHC years
40 LHC years
50 LHC years
Accumulated Charge per cm of anode wire ( Part A)
0
0.1
0.2
0.3
0.4
0.5
0 20 40 60 80 100 120 140 160 180
Time [Days]
Dose
[C/c
m]
Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6
10 LHC years = 0.08 C/cm
30 LHC years
20 LHC years
10 LHC years
40 LHC years
50 LHC years
Layer 1, 6 - reference
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 13
Gas Gain
0.70
0.80
0.90
1.00
1.10
1.20
0.000 0.050 0.100 0.150 0.200 0.250 0.300
Accumulated charge per cm of Wire (C/cm)
Rel
ativ
e cu
rrent
s
i2*2.(i1+i6) i3*2./I1+i6)i4*2.(i1+i6) i5*2.(i1+i6)
0.70
0.80
0.90
1.00
1.10
1.20
0.000 0.050 0.100 0.150 0.200 0.250 0.300
Accumulated charge per cm of Wire (C/cm)
Rel
ativ
e cu
rrent
s
i2*2.(i1+i6) i3*2./I1+i6)i4*2.(i1+i6) i5*2.(i1+i6)
Aging Test 2000
Gas Gain remained unchangedGas Gain remained unchanged
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4Accumulated charge per cm of Wire (C/cm)
Rel
ativ
e cu
rren
ts
Layer 2 Layer 3Layer 4 Layer 5
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4Accumulated charge per cm of Wire (C/cm)
Rel
ativ
e cu
rren
ts
Layer 2 Layer 3Layer 4 Layer 5
Aging Test 2001
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 14
Dark Current
Aging Test 2001
0.1
1
10
100
1000
0 0.1 0.2 0.3 0.4Accumulated Charge per cm of wire (C/cm)
Dar
k C
urre
nt, n
A
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
Aging Test 2001
0.1
1
10
100
1000
0 0.1 0.2 0.3 0.4Accumulated Charge per cm of wire (C/cm)
Dar
k C
urre
nt, n
A
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
Aging Test 2000
0.1
1
10
100
1000
0 0.05 0.1 0.15 0.2 0.25 0.3Accumulated charge per cm of wire (C/cm)
Dar
k cu
rren
ts,
nA
I1 I2 I3I4 I5 I6
Aging Test 2000
0.1
1
10
100
1000
0 0.05 0.1 0.15 0.2 0.25 0.3Accumulated charge per cm of wire (C/cm)
Dar
k cu
rren
ts,
nA
I1 I2 I3I4 I5 I6
Dark current increased from ~1 nA to typically ~10 nA per plane
Dark current increased from ~1 nA to typically ~10 nA per plane
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 15
Dark Rates
Dark rates
1
10
100
1000
10000
0 0.1 0.2 0.3 0.4Accumulated charge per cm of wire (C/cm)
Aver
age
wire
rate
s, H
z Layer #1 Layer #2Layer #3 Layer #4Layer #5 Layer #6
Dark rates
1
10
100
1000
10000
0 0.1 0.2 0.3 0.4Accumulated charge per cm of wire (C/cm)
Aver
age
wire
rate
s, H
z Layer #1 Layer #2Layer #3 Layer #4Layer #5 Layer #6
Aging Test 2001
Noise count remained unchangedfor both runs in 2000 and 2001
Noise count remained unchangedfor both runs in 2000 and 2001
Dark rates
1
10
100
1000
10000
0.0 0.1 0.2 0.3 0.4Accumulated charge per cm of wire (C/cm)
Ave
rage
wire
rate
s, H
z
Layer 1 Layer 2 Layer 3Layer 4 Layer 5 Layer 6
Dark rates
1
10
100
1000
10000
0.0 0.1 0.2 0.3 0.4Accumulated charge per cm of wire (C/cm)
Ave
rage
wire
rate
s, H
z
Layer 1 Layer 2 Layer 3Layer 4 Layer 5 Layer 6
Aging Test 2000
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 16
2001
0.1
1
10
100
1000
10000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Accumulated Charge per cm of wire (C/cm)
Res
ista
nce,
GO
hm
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
2001
0.1
1
10
100
1000
10000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Accumulated Charge per cm of wire (C/cm)
Res
ista
nce,
GO
hm
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
Strip to Strip Resistance
2000
0.1
1
10
100
1000
10000
0 0.05 0.1 0.15 0.2 0.25 0.3Accumulated Charge per cm of wire (C/cm)
Res
ista
nce,
GO
hm
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
2000
0.1
1
10
100
1000
10000
0 0.05 0.1 0.15 0.2 0.25 0.3Accumulated Charge per cm of wire (C/cm)
Res
ista
nce,
GO
hm
Layer 1 Layer 2 Layer 3
Layer 4 Layer 5 Layer 6
Aging Test 2000 Aging Test 2001
Resistance between StripsChanged from ~100 to ~ 10 − − − − 100 GOhm during irradiation
Resistance between StripsChanged from ~100 to ~ 10 − − − − 100 GOhm during irradiation
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 17
Cathode Plane Deposits
Cathode planes:
� thin uniform layer of deposits:
� extends beyond the irradiated zone
� also, found on the last plane (along gasflow) that had HV off during irradiation
� Composition of deposits: O, F, Si
Cathode planes:
� thin uniform layer of deposits:
� extends beyond the irradiated zone
� also, found on the last plane (along gasflow) that had HV off during irradiation
� Composition of deposits: O, F, Si
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 18
Anode Wires
Anode wires:
� Wires stayed fairly clean
� With some minor deposits,sporadically scattered
Anode wires:
� Wires stayed fairly clean
� With some minor deposits,sporadically scattered
Oleg Prokofiev Aging Phenomena in Gaseous Detectors, DESY, Hamburg 2001 19
Summary
• Aging tests with two CMS Cathode Strip Chambers wereperformed
• In one of the two tests a closed loop gas system was used
• At accumulated dose of 0.3-0.4 C/cm (30 – 40 LHC years)no significant changes in chamber performance (dark current, noise count, gas gain, efficiency) were observed
• Strip-to-strip resistance decreased but stayed well within technical specification (> 1.0 MOhm)
• Accumulation of deposits on the cathode planes was observedwhile wires stayed fairly clean
All test showed that CMS CSCs with Ar/CO2/CF4 gas mixture could be run in the LHC environment without appreciable aging effects
• Aging tests with two CMS Cathode Strip Chambers wereperformed
• In one of the two tests a closed loop gas system was used
• At accumulated dose of 0.3-0.4 C/cm (30 – 40 LHC years)no significant changes in chamber performance (dark current, noise count, gas gain, efficiency) were observed
• Strip-to-strip resistance decreased but stayed well within technical specification (> 1.0 MOhm)
• Accumulation of deposits on the cathode planes was observedwhile wires stayed fairly clean
All test showed that CMS CSCs with Ar/CO2/CF4 gas mixture could be run in the LHC environment without appreciable aging effects