aging tests of full scale cms cathode strip muon chambers · oleg prokofiev aging phenomena in...

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


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)


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


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


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


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


Aging Test at GIF

ME1/2 Chamber at GIFChamber Test


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)


Closed Loop Circulation Gas System


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


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


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


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]


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]


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


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


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


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



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


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


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



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



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



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



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


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


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


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

aging tests of full scale cms cathode strip muon chambers · oleg prokofiev aging phenomena in...

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