ageing studies material tests update ageing tests with methane – extrapolation to alice conditions...
TRANSCRIPT
AGEING STUDIESAGEING STUDIES
• Material tests update• Ageing tests with Methane
– Extrapolation to ALICE conditions– Extrapolation to STAR conditions
C. Garabatos, GSI
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 2
Tested materialsMaterial S/F (h/cm) mC/cm Result
Tedlar 1 (*) 0.3 3.2 OK
Araldit 2013 0.01 13 OK
Araldit DP190 0.35 9 OK
Araldit 2012 0.35 5.8 OK
Araldit 116 0.35 9 OK
Tedlar 2 (*) 2.2 4.3 OK
(*) ALICE: 34 h/cm
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 3
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 4
Ne-CO2 [90-10] Gain ~ 24 000
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 5
Gain with P10
1250 1300 1350 1400 1450 1500 15501000
10000
100000
Ar-CH4 [90-10] in Module 18
Ga
in
Anode voltage (V)
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 6
First ageing test:ended with Malter breakdown
0.0 0.1 0.2 0.3 0.4 0.5800
810
820
830
840
850
P10G
0 = 24000
i0 ~ 10 nA/cm
P
eak
posi
tion
(a.u
.)
mC/cm
20
21
22
23
24
25
Energ
y resolu
tion (%
)
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 7
Second ageing test:ended with Malter breakdown
0.0 0.2 0.4 0.6 0.8 1.0400
420
440
460
480
500P10, G
0 = 14000
i0 ~ 6 nA/cm, R' ~ 7.7 (C/cm)-1/2
P
eak
po
sitio
n (
a.u
.)
mC/cm
20
24
28
32
36
40
En
erg
y resolu
tion
(%)
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 8
Characterization of the Rate of ageing
0.0 0.1 0.2 0.3 0.4 0.5400
410
420
430
440
450
460
470
480
490
500
G
ain
(a
.u.)
q (mC/cm)
0
2
4
6
8
10
12
14
16
18
20
G/G0 = exp{-R q}
G/G0 = exp{-R'q}
R' (m
C/cm
) -1/2 R/1
00
(mC
/cm) -1
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 9
Rate of ageing in ALICE with P10
qRGG '0 exp
0.01 0.1 1 10 100 10000.1
1
10
100
ALICE TPC(max)
R' [
(C/c
m)-1
/2]
Initial intensity (nA/cm)
Fischer et al. Au wire Au, Graphite cathode SS wire SS, CH
4 45
Au, 1 % water ALICE ROC, P10
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 10
Estimation of rates and doses
BOE dN/dY Sec.
track length (cm)
wire length (cm)
# of wires
wire pitch (cm)
Ne
(cm-1) GainTrig.
rate (Hz)
ALICE 8000 x2 163 60 656 0.25 45 20000 200+40
STAR 650 x2 150 65 300 0.4 85 4000 20
Methodcharge
density (C)current
(nA/cm)
dose
(mC/cm)
ALICEMarek
Max. (TDR)0.510-12
/20cm1.0 10 in 10 yr
ALICEMarek Sector
3.010-12
/sector0.37 3.7 in 10 yr
ALICEBOE
Sector1.010-12
/sector0.13 1.3 in 10 yr
STARBOE
Sector.000210-
2 /sector0.0009*
.035* in 3 months
* Scale by factor 5
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 11
Ageing predictions
1E-3 0.01 0.1 1 100.3
0.4
0.5
0.6
0.7
0.8
0.9
1
ALICE10 years
STAR3 months
G/G
0
q (mC/cm)
R' = 0.1 (C/cm)-1/2
R' = 0.5 R' = 1 R' = 5 R' = 10
1E-3 0.01 0.1 1 10 100 10000.1
1
10
100
STAR TPC(max)
ALICE TPC(max)
R' [
(C/c
m)-1
/2]
Initial intensity (nA/cm)
Fischer et al. Au wire Au, Graphite cathode SS wire SS, CH
4 45
Au, 1 % water ALICE ROC, P10
TPC C.M. 2-3.06.03 C. Garabatos, GSI Darmstadt 12
Conclusions
Materials tested so far are most probably fine for the ALICE TPC
Methane is out of the questionIt produces severe ageing well within the time
scale of ALICEIROCs would breakdown in the first yearMethane is a safety nightmare
Next test: Vacuum grease for O-rings