High intensity beam studies of sparks in resistively- coated and standard Micromegas detectors...
Transcript of High intensity beam studies of sparks in resistively- coated and standard Micromegas detectors...
High intensity beam studies of sparks in resistively-coated and standard Micromegas detectors
Within the MAMMA collaboration
Arizona, Athens(U, NTU, Demokritos), Brookhaven,
CERN, Harvard, Istanbul, Naples, CEA Saclay, Seattle, USTC Hefei, South Carolina, St. Petersburg, Shandong,
Stony Brook, Thessaloniki
Shuoxing Wu / CEA Saclay, USTC Hefei
D. Attié, T. Alexopoulos, M. Boyer, P. Colas, J. Derré, F. Diblen, E. Ferrer Ribas, T. Geralis, A. Giganon, I. Giomataris, F. Jeanneau,
K. Karakostas, S. Kirch, E. Ntomari, M. Titov, W.Wang
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• Sparks will be a problem in SLHC conditions with today’s Micromegas detectors
• Sparks induce dead time and can damage the detector if persistent
• Possible solutions– Resistive films – Segmented mesh– Double amplification
Outline:
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Measurements done at the lab:
Gain curves (resistives detectors) (Ar+2%C4H10+3%CF4) Edrift: 200V/cm
100
1000
10000
100000
360 365 370 375 380 385 390 395 400 405 410 415 420 425
V mesh
gain
gain SLHCR2 gain SLHCR3
gain SLHCR4 gain SLHCR5
gain SLHCR6 gain SLHCR7
Gain curves (no resistives detectors) (Ar+2%C4H10+3%CF4) Edrift: 200V/cm
100
1000
10000
100000
360 365 370 375 380 385 390 395 400 405 410 415
V mesh
gain
gain proto1 gain proto3
gain proto4 gain proto5
gain proto6 gain proto7
gain proto8 gain proto9
gain SLHC1 gain SLHC1.1
gain SLHC2 gain SLHC3
All the resistive detectors are tested at the test beam
SLHC2 and SLHC3 are used as the reference detectors at the test beam
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Test beam set up:• Time: 13-19 Nov 2009
• Telescope:
3 X-Y detectors(10 x 10 cm2) manufactured at Saclay
• Aim: Test different resistive films detectors
manufactured by Rui De Oliveira at CERN and
compare behaviour to non-resistive detectors
• Electronics: GASSIPLEX
• DAQ: realised by Demokritos
• Gas: 95%Ar + 3% CF4 + 2% isobutane
120 Gev π+
Y
ResistiveN
on-Resistive
X Y X X
Beam
1 mm 0.25 mm 1 mm
Detectors in test
YTested detectors:standard bulk detectors; 2 M Ω/ Resistive kapton: R3&R4;250 M Ω/ Resistive paste: R5; 400K Ω/ Resistive strips: R6;Few tens of k Ω/ resistive pads: R7; Segmented one: S1.
SPS-H6
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Readout and online monitoring:
Data acquistion based on Labview: Monitoring through raw data by C++/Root code:
…It’s easy to reconstruct the beam profile...
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Spark counting device:
MM detector
C=50 pF
R1=5,6 kΩ R2=5,6 kΩ
C=470 pF
HVmesh
Pre-amplifer
Shaper Voltage-Current monitoring PC
for standard ones for resistive ones
Different sparking behaviours of standard and resistive detector:
Standard SLHC2(@10KHz): Resistive R3(@wide beam,15KHz):
250
270
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1 77 153 229 305 381 457 533 609 685 761 837 913 989 10651141121712931369144515211597Spark number
V
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1 uAMesh Vol tageMesh Current
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270
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390
410
430
1 29 57 85 113141 169197 225253281 309337 365393 421449477 505533 561589617 645673 701Spark number
V
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
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1 uAR3 mesh vol tageR3 mesh current
SLHC2: HV=400 V (Gain ~3000): current when sparking < 0.5 A voltage drop< 5%R3: HV=410 V (Gain ~3000): current when sparking < 0.2 A voltage drop< 2%
S1: Segmented mesh
one sparking
two sparking
four sparking
three sparking
five sparking
six sparking
seven and eight sparking
Spark rate= #Sparks/#incident hadron
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270
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390
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1 92 183 274 365 456 547 638 729 820 911 1002109311841275136614571548
V
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
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Spark number
uAS1 mesh vol tageS1 mesh current
0. 00E+00
2. 00E-05
4. 00E-05
6. 00E-05
8. 00E-05
1. 00E-04
1. 20E-04
1. 40E-04
1. 60E-04
370 380 390 400 410
Vmesh
Spar
k nu
mber
/had
ron
S1SLHC2
Spark rate@10KHz:
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R3 spark rate(@10KHz):
R3 /R4: 2 M Ω/ Resistive kapton + insulator
Without breakdown!0. 00E+00
2. 00E-06
4. 00E-06
6. 00E-06
8. 00E-06
1. 00E-05
1. 20E-05
1. 40E-05
1. 60E-05
380 390 400 410 420 430 440 450
Vmesh
Spar
k nu
mber
/had
ron
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R5 spark rate(@10KHz):
250 M Ω/ Resistive paste + insulator
0. 00E+00
5. 00E-05
1. 00E-04
1. 50E-04
2. 00E-04
2. 50E-04
3. 00E-04
3. 50E-04
4. 00E-04
4. 50E-04
5. 00E-04
380 390 400 405 410Vmesh
Spar
k nu
mber
/had
ron
HV=390 V (gain~3000): current when sparking<0.1 A
voltage drop<1.5%
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Spark rate R6(@10KHz): 400K Ω/ Resistive strips (paste)
Break down!1. 00E-06
1. 00E-05
1. 00E-04
1. 00E-03
370 380 390 400 410 420 430
Vmesh
Spar
k nu
mber
/had
ron
HV = 390 (gain~3000): current when sparking < 0.08 A
voltage drop < 0.5%
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R7 spark rate(@10KHz):
a few tens of kΩ/Resistive pads (paste)
5. 20E-04
5. 40E-04
5. 60E-04
5. 80E-04
6. 00E-04
6. 20E-04
6. 40E-04
390 400 410
Vmesh
Spar
k nu
mber
/had
ron
HV = 400V (gain~3000): current when sparking< 0.35A
voltage drop< 4.5%
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Detector type Spark rate Spark current /A
Voltage drop
SLHC2 standard 7*E-5 0.4 5%
R3 2 M Ω/
resistive kapton9.6*E-6 0.2 2%
R5 250 M Ω/
resistive paste1.6*E-4 0.1 1.5%
R6 400K Ω/
resistive strip6.4*E-6 0.08 0.5%
R7 tens of K Ω/
resistive pad5.9*E-4 0.35 4.5%
Detector performance at same gas gain (~3000):
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Conclusions and outlook:
1. Resistive detectors R3 and R6 can reduce the spark rate by one magnitude, R5 and R7 increase the spark rate, they are not successful ones.
2. All the resistive detectors can reduce the spark current and voltage drop by a factor of 2-10, thus provide a better working performance for high luminosity SLHC period.
3. Performance such as efficiency and spatial resolution need to be done later to compare between the resistive one and standard one, at least we had a very successful data taking…