Performance of gas sealed RPCs
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Transcript of Performance of gas sealed RPCs
PERFORMANCE OF GAS SEALED RPCS
M.Bhuyan, S.D.Kalmani, N.K.Mondal, S.Pal, Deepak Samuel, B.Satyanarayana and R.R.Shinde
Gouranga Kole, Chiraag Lala and Kanishka Rawat
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Requirement of gases in ICAL
GasAvalanch
e(%)
Streamer
(%)Maximum
(%)Volume
(L)Density
(g/L)Weight
(Kg)Cost
(Rs/Kg)
Argon 0.0 30.0 30.0 58,503 1.784 104.4
R134a 95.5 62.0 95.5 186,234.6 4.25 791.5
Isobutane 4.3 8.0 8.0 15,600.8 2.51 39.16
SF6 0.2 0.0 0.2 390 6.164 2.40
Total number of RPCs in ICAL = 3 150 64 = 28,800Total gas volume = 28,800 184cm 184cm 0.2cm = 195,010 litresFor example: One volume change/day with 10% gas top-up in a re-circulating schemeApproximate running gas cost = Rs 30,000/day (R134a from Mafron)
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Motivation for this study Recycling of gas mixture for reduction of gas
cost and complying with environmental regulations.
Further reduction in the operating cost of ICAL in the long run without compromising on the detector efficiency and performance.
Study contamination and formation of radicals in the gas mixture flowing through the RPCs.
These kind of studies do not seem to have been performed by other researchers.
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
The first studyOne 1m×1m RPC (called AB13) was sealed on
February 5, 2010. Its operating parameters such as strip rate and current were monitored 24×7, along with laboratory temperature and
relative humidity. After 130 days of
uninterrupted operation, the gas
inside RPC was analyzed using a
Residual Gas Analyzer (RGA)
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Lab temperature & noise rate
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Noise rates of 8 strips
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Lab temperature & current
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
RGA analysis - 140
332
0 69
28
RGA spectra was collected with background of Argon.
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
RGA analysis – 228
33
6983
Removing the background Argon spectra, major fragment was at mass no. 28
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
RGA analysis - 333
69
8351
Removing the air background , major fragment was at mass no. 33
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Summary of RGA RGA spectra
contains nearly 50% air and 3% water vapour.
RPC AB13 was sealed for 130 days.
Amount of air accumulated ~1000ml.
Therefore, the leak rate ~8ml/day.
Major fragments of pure gases
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Sealed gas test for C217 stack
Stack of 12 1m×1m RPCs L0, L4 and L11 were used as reference Other RPCs sealed on April 27, 2010
Summary of the study
Sl. no
Layer No
RPC Name
Sealing date
Gas flow restarted
No of days sealed
1 L00 AB06 -------------- -------------- --2 L01 AB07 27-Apr-10 19-Jul-10 833 L02 AB10 27-Apr-10 19-Jul-10 834 L03 AB11 27-Apr-10 31-May-10 345 L04 AB09 -------------- -------------- --6 L05 IB02 27-Apr-10 19-Jul-10 837 L06 AB02 27-Apr-10 29-May-10 328 L07 AB01 27-Apr-10 29-May-10 329 L08 AB03 27-Apr-10 19-Jul-10 8310 L09 AB04 27-Apr-10 29-May-10 3211 L10 AB12 27-Apr-10 28-May-10 3112 L11 AB08 -------------- -------------- --
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Reference and sealed RPC
020406080
100120140160
28-Mar 12-Apr 27-Apr 12-May 27-May 11-Jun 26-Jun 11-Jul 26-Jul 10-Aug
Cur
rent
(nA
)
AB06_+ve AB06_-ve
050
100150200250300350400
28-Mar 12-Apr 27-Apr 12-May 27-May 11-Jun 26-Jun 11-Jul 26-Jul 10-Aug
Cur
rent
(nA
)
AB04_+ve AB04_-veA
B
A= RPC Sealed for 32 days B = Gas flow restarted
Reference RPC
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
RPCs sealed for 83 days
0
50
100
150
200
250
300
350
400
28-Mar 12-Apr 27-Apr 12-May 27-May 11-Jun 26-Jun 11-Jul 26-Jul 10-Aug
Cur
rent
(nA
)
AB07_+ve AB07_-ve
0
50
100
150
200
250
300
28-Mar 12-Apr 27-Apr 12-May 27-May 11-Jun 26-Jun 11-Jul 26-Jul 10-Aug
Cur
rent
(nA
)
IB02_+ve IB02_-ve
A
A
B
B
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Comparison of leaky RPCs
0
50
100
150
200
250
300
350
21-Feb 23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep 19-Oct
Strip
Rat
e (H
z)
L00L06L05
A
B
C
A = Sealed (L05, L06) B = Flow started (L06) C = Flow started (L05)
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Repair of leaky RPCs
Pressurise the chamber to 20-30mm water column.
Look for the leak. Locate the leaks using gas
sniffer. Plug the leaks with glue. Redo the above till all the
leaks are plugged.
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Summary of sealed gas testLayer RPC
Id Test L rate I end I begin I I rate R end R
begin R R rate
(Days) (mm/hr) (nA) (nA) (nA) (nA/
day) (Hz) (Hz) (Hz) (Hz/day)
0 AB06 (Ref) TBD - - - - - - - -
1 AB07 83 TBD 241 38 203 2.4 416 15 401 4.8
2 AB10 83 1.3 190 19 171 2.1 505 30 475 5.7
3 AB11 34 12 262 47 215 6.3 377 81 296 8.7
4 AB09 1 72 - - - - - - - -
5 IB02 83 TBD 120 68 52 0.6 100 40 60 0.7
6 AB02 32 TBD 302 69 233 7.3 377 37 340 10.6
7 AB01 32 TBD 266 67 199 6.2 344 45 299 9.3
8 AB03 83 TBD 182 21 161 1.9 256 52 204 2.5
9 AB04 32 TBD 355 55 300 9.4 1067 70 997 31.2
10 AB12 31 10 492 46 446 14.4 934 31 903 29.1
11 AB08 (Ref) 12 - - - - - - - -
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Conclusions Different rate of change of strip rate and
current with time may be attributed to different leak rate for different RPCs.
With proper sealing condition, the detector can run for at least one month, once filled, reducing the cost by factor of 30.
The gas can be recovered efficiently with more contaminants by reusing the same gas for longer period of time.
All the RPC parameters have come back to their earlier values after reflowing fresh gas through RPCs.
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Tracking efficiency & Multiplicity (L0,L04,L11)
707580859095
100
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Effic
ienc
y (%
)
EFF_X0EFF_X4EFF_X11
0
1
2
3
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Mul
tiplic
ity MULT_X0MULT_X4MULT_X11
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Tracking efficiency & Multiplicity (L3,L6,L7,L9)
0
1
2
3
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Mul
tiplic
ity MULT_X3MULT_X6MULT_X7MULT_X9
80
85
90
95
100
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Effic
ienc
y (%
)
EFF_X3EFF_X6EFF_X7EFF_X9
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011
Tracking Efficiency & Multiplicity (L1,L2,L5,L8)
0
1
2
3
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Mul
tiplic
ity MULT_X2MULT_X5MULT_X8MULT_X1
70
75
80
85
90
95
100
23-Mar 22-Apr 22-May 21-Jun 21-Jul 20-Aug 19-Sep
Effic
ienc
y (%
)
EFF_X2EFF_X5EFF_X8EFF_X1
B.Satyanarayana, TIFR, Mumbai INO Collaboration Meeting, Madurai January 23-26, 2011