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Construction and commissioning of a setup to study ageing phenomena in high rate gas detectors. Alhussein Abuhoza , S. Biswas , U. Frankenfeld, J. Hehner , C. Schmidt GSI, Darmstadt, Germany and H.R. Schmidt University of Tübingen , Germany. TIPP14 Amsterdam (2-6.6.2014). Plan. - PowerPoint PPT Presentation
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Alhussein Abuhoza, S. Biswas, U. Frankenfeld, J. Hehner, C. Schmidt
GSI, Darmstadt, Germanyand
H.R. Schmidt University of Tübingen, Germany
Construction and commissioning of a setup to study ageing phenomena in
high rate gas detectors
TIPP14 Amsterdam (2-6.6.2014)
Introduction What is the detector ageing? Why ageing studies?
Ageing setupSetup-ISetup-II
Summary
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Plan
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Introduction What is the detector ageing? Why ageing studies?
Ageing setupSetup-ISetup-II
Summary
Symptoms
Losses in gas gain
Decrease of resolution
or efficiencyExcessive currents Etc...
Detector ageing
It is the deterioration of the detector performance.
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Introduction What is the detector ageing? Why ageing studies?
Ageing setupSetup-ISetup-II
Summary
~1.5 C/cm2 Estimated accumulated charge in the fourth layer of
Muon Chamber (MuCh) in CBM Ex. in
10 years.
~300 C/cm2 Estimated
accumulated charge in the first
layer of Muon Chamber (MuCh)
in CBM Ex. in 10 years.
~11 C/cm2 Estimated
accumulated charge at TRD1 in CBM Ex. in 10
years.
Experiment like Compressed Baryonic Matter (CBM)
at future FAIR facility at Darmstadt, Germany needs
detectors with long term (~10 years) stable operation
at high rates.
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Introduction What is the detector ageing? Why ageing studies?
Ageing setupSetup-ISetup-II
Summary
Ageing setup
1. Studying ageing phenomena of gaseous detectors.2. Investigating the ageing properties of the materials used
for the construction of gaseous detectors.3. Monitoring the performances of gaseous detectors, in
particular those used in CBM.
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Setup-I
• Two MWPCs in serial were used in setup-I.
• A mixing station fids one gas line.• One sensor for temperature and one
for pressure.• The MWPC configured of two cathodes
(Al-Kapton foils) and on anode (multi-wire plane).
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Setup-I (Test approach)
t
t
Q Q
MaMa
Mr Mr
Fully Automatic
Ageing Chamber
Reference Chamber
High rate
X-ray55Fe
monitor
X-ray
Ageing Ch.Refernce Ch.
Nor
mal
ized
gai
n
∑Q
No ageing
Ageing
Gain in MWPC
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Ageing study :1. Gain is the major parameter to monitor detector performance.
2. Gain normalization: Gain ratio of two detectors (ageing and reference).
Extrapolating gas density effect by fitting approach (needs precise measurement of gas temperature and pressure).
3. Variation of normalized gain should be < 1%
p/T
G
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1. Cathode of Al-Kapton foil has been replaced with a multi-wire plane
2. Premixed gas bottle will be used instead of a mixing station (temperature effect on the MFCs).
3. Moving platforms have to be presented (to avoid the continuous exposure of 55Fe-source and to test two materials or more in parallel).
4. Metal housing of chamber instead of fiberglass .5. Individual gas lines (to avoid any pressure drop in-between the chambers).
Findings from setup-I
[1] A Abuhoza, S Biswas, U Frankenfeld, J Hehner, CJ Schmidt, and HR Schmidt. Physics Procedia, 37:442–447, 2012.[2] A Abuhoza, HR Schmidt, S Biswas, U Frankenfeld, J Hehner, and CJ Schmidt. NIM Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012.
Introduction What is the detector ageing? Why ageing studies?
Ageing setupSetup-ISetup-II
Summary
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Setup-II (components)
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Setup-II• Three parallel lines (two for ageing test, one reference).• Premixed gas (no mixing station).• Two motion platforms (collimator and chambers).• Metal housing of the chambers.• Multi wire anode + multi wire cathode.
(components)
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Setup-II
Dimension of setup box : 110×130×83 cm
Dimension of MWPC: 20×20 cmActive area: 10×10 cm LabView program operates all
the functions automatically
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Setup-II (Gas system)
Outgassing box
Ageing material
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Setup-II(Test procedure)
motor
motor
CH-0CH-2CH-1
x-ray
CH-1
CH-0
CH-2
tN
orm
aliz
ed g
ain
∑Q
ageing
No ageing
1. 55Fe2. X-ray (filter)
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Commissioning and ageing tests of setup-II
Ageing and recovery behavior in the first test.
Investigation of setup cleanness.
Improving of gain normalization.
Ageing tests.
Ageing and recovery behavior in the first test.
In this setup all the components are new:+ Detector Lab (D.L.) global gas-line + Mass flow Controller (MFC)+ rigid steel tubes inside the lab + outgassing box (in line-1 and line-2) + flexible steel tube (inlet) + detector + flexible steel tube (outlet)
55Fe1mm
55Fe+x-ray1mm+3cm
Effect of the high rate of x-
ray ??
Where is the contamination source in the new setup??
ΔG=7%
ΔG=4%
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Investigation of contamination source
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Investigation of contamination source
(ΔG/G0)CH-0 = 5%(ΔG/G0)CH-1 = 11%
Using two lines
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Investigation of contamination source
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Investigation of contamination source
• Two ageing tests using gas scheme-2 revealed that there is still a source of ageing.
ΔG/G0 = 2.5%
Using one line
ΔG/G0 = 20%
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Investigation of contamination source
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Investigation of contamination source
Gas system: ball gas flow regulator + flexible steel tube + flexible steel tubes (inlet) + detector + flexible steel tubes (outlet) + outgassing box (some tests)
ΔG/G0 = 5%
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Investigation of contamination source
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Investigation of contamination source
Gas system: ball gas flow regulator + copper tube (inlet) + detector + copper tube (outlet)
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Flexible tubes were cleaned by the supplier with a cleaning and degreasing agent is called
commericialy “A062-K21 hebro®lan TN” contains:
• Phosphoric acid• Alkyl alcohol ethoxylate• Methylethyl ester• Amins• Alhkyldmiethyl• N-oxides
Investigation of contamination source
Cleaning procedures of flexible tubes:1. Distilled water, iso-propanol and dry air are pumped through
the rigid and flexible tubes (without taking them out from the setup).
2. Ultrasonic bath + iso-propanol pumping.
Gain variation = 0.3%
ΔG/G0 = 5%
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Improving of gain normalization .
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• RTV-3145
• Al-tape (Gerband 705)
Area=135 cm2
R= 300 %/C/cm
Area=135 cm2
R= 3180 %/C/cm
• Ageing test of RTV-3145 and Al-tape (Gerband 705)
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Summary
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Precise measurement of ageing are necessary to implement studies in reasonable time and in real conditions.
Very clean and stable apparatus dedicated to ageing studies is operational in GSI DetLab.
Ageing acceleration by x-ray needs to be investigated. Obtained gain stability is < 0.5% peak-to-peak. Cleaning and degreasing agent “A062-K21 hebro®lan TN” reveals
ageing effect on the MWPC. Ageing test for two materials have been carried out (accelerated by x-
ray generator): RTV-3145 : R=3180 %/C/cm Gerband 705: R=300%/C/cm
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•Back up
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R= 960 %/C/cm2 , Q=0.117 C/cm2
R= 92 %/C/cm2 , Q=0.037 C/cm2
10 years = 10*2*30*24= 14400 hQ=e·n·r·G·t
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• Polyacrylat
Ageing tests:
1 min 1 min 1 min + 40 min x-ray
Ch-2Ch-1Ch-0
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Residual instability has been observed due to
change in the gas density and detector geometry
resulting from the change of ambient parameters (T,
P etc.)
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Modification in the design
Inner windows
Outer windows
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To avoid the residual fluctuation of the gain resulting from the change of geometry of the
chamber, extra outer windows have been added with two holes in inner windows
• Diethornís formula
Unstable proportionality of the gain with T/p ratio
T/P (K/bar)
Stable proportionality of the gain with T/p ratio
T/P (K/bar)
With outer windows
Very stable operation after
correction
Unstable after correction
Without outer
windows
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