status on pwo crystals from bogoroditsk after one year of preproduction for cms-ecal
DESCRIPTION
STATUS on PWO crystals from Bogoroditsk after one year of preproduction for CMS-ECAL. Etiennette Auffray SCINT 99, 16 August 1999. Importance of R&D effort. 95. 98. Since the 4th September 98, we received : 1000 preproduction crystals from BTCP: 100 : 04/09/98 100 : 03/11/98 - PowerPoint PPT PresentationTRANSCRIPT
August 99 E.Auffray CMS/ECAL
STATUS on PWO crystals from Bogoroditsk
after one year of preproduction for CMS-ECAL
Etiennette Auffray
SCINT 99, 16 August 1999
August 99 E.Auffray CMS/ECAL
Importance of R&D effort
95 98
0
10
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80
90
100
300 350 400 450 500 550 600 650 700
Tran
sm
issio
n (
%)
Wavelength (nm)
Theoretical transmission from Fresnel losses
95 crystal98 crystal
August 99 E.Auffray CMS/ECAL
Since the 4th September 98, we received :1000 preproduction crystals from BTCP:
100 : 04/09/98100 : 03/11/98200 : 08/12/98 200 : 22/03/99 400 : 22/06/99
All have been visually Inspected•All have been characterised with ACCOS(Automatic machine to measure :
3D, transmission, decay time,LY)•Some have been irradiated
•61 irradiated in High dose rate (500Gy, 240Gy/h)•129 irradiated in Low dose rate (3Gy, 0.15Gy/h)
•400 used for the 1st module of CMS/ECALin CERN/lab27 regional center
First crystals La doped&
progressively changed to Y-Nb doped
August 99 E.Auffray CMS/ECAL
Reception of first 100 preproduction crystals
August 99 E.Auffray CMS/ECAL
Quality check of first 1000 preproduction crystals
August 99 E.Auffray CMS/ECAL
Optical Specifications for Preproduction
Longitudinal transmission
10% at 350nm
55 % at 420nm
65 % at 600nm Transversal transmission
– For T=50% 6nm
S >1.5 %/nm between 340 and 370nm
For “blue” crystals :
LY in labo27 at 8Xo 8 pe/MeV
2 pe/MeV with 1 EG&G APD (BT97)
Decay time
LY(100ns)/LY(1s) > 90%
No visible afterglow » < 0.5% background with 1MBq source in standart
decay time measurement
Good radiation Hardness
August 99 E.Auffray CMS/ECAL
Bogoroditsk Preproduction Status
0
200
400
600
800
1000
Sep
Nov
Jan
Mar
May
Jul
Sep
Nov
Jan
Mar
May
Planning Delivered
16 August, 99
1500 crystals delivered Mid of August
1998 1999 2000
August 99 E.Auffray CMS/ECAL
Dimensions
02468
101214161820222426283032343638404244464850
Range m
AR-Nominal value
Batch 119/100 rejected
19%
On all dimensions
02468
101214161820222426283032343638404244464850
Range m
Batch 214/100 rejected
14%
0102030405060708090
100110120130140150160170180190200
Range mm
Batch 219/200 rejected
8.5%
-100 0
August 99 E.Auffray CMS/ECAL
020406080
100120140160180200220240260280300320340360380400
Range mm
Dimensions AR-Nominal value
Batch 48/200 rejected
4%
On all dimensions
Batch 59/400 rejected
2.25 %
-100 0
048
12162024283236404448525660646872768084889296
100
Range m
August 99 E.Auffray CMS/ECAL
420nm Optical Transmission
0
10
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40
50
60
70
80
90
100
300 350 400 450 500 550 600 650 700 Wavelength (nm)
0
50
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250
300
30 35 40 45 50 55 60 65 70 75 80Transmission at 420nm (%)
Distribution for 1000 crystals
3.2%below 55%
August 99 E.Auffray CMS/ECAL
420nm Optical Transmission
Batch 111/100 rejected
11%
Batch 26/100 rejected
6%
Batch 315/200 rejected
7.5%
0
5
10
15
20
30 35 40 45 50 55 60 65 70 75 80
Nu
mber
of
cry
sta
ls
Transmission at 420nm (%)
Mean Value : 61.47%Standard dev. : 4.85%
0
2
4
6
8
10
30 35 40 45 50 55 60 65 70 75 80
Nu
mber
of
crys
tals
Transmission at 420nm (%)
Mean value: 61.88%Standard dev. : 7.5%
0
2
4
6
8
10
12
14
30 35 40 45 50 55 60 65 70 75 80
Nu
mber
of
cry
stals
Transmission at 420nm (%)
Mean value: 62.32%Standard dev. : 5.38%
August 99 E.Auffray CMS/ECAL
420nm Optical Transmission
Batch 40/200 rejected
0%
0
10
20
30
40
50
30 35 40 45 50 55 60 65 70 75 80
Nu
mber
of
cry
sta
ls
Transmission at 420nm (%)
Mean value: 66.84%Standard dev. : 2.74%
0
50
100
150
200
30 35 40 45 50 55 60 65 70 75 80Transmission at 420nm (%)
Mean Value : 68.49%Standard dev. : 1.66%
Batch 50/400 rejected
0%
August 99 E.Auffray CMS/ECAL
0
50
100
150
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250
300
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16LY (pe/MeV)
Light Yield
0
1
2
3
4
5
6
7
8
9
10
11
12
0 50 100 150 200 250Distance from front side (mm)
Distribution for 1000 crystals
LY at 8Xo
2.2% below 8pe/MeV
August 99 E.Auffray CMS/ECAL
Light Yield
0/100 rejected0%
0/100 rejected0%
1/200 rejected0.5%
Batch 3
Batch 2
Batch 1
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Nu
mber
of
cry
sta
ls
Ly at ACCOS at 8Xo (pe/MeV)
Statistic on 100crystalsMean Value : 10.67pe-/MeV
Standard deviation : 1.05pe-/MeV
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Nu
mber
of
cry
sta
ls
Ly at ACCOS at 8Xo (pe/MeV)
Statistic on 200crystalsMean Value : 9.86 pe-/MeV
Standard deviation : 1.74pe-/MeV
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Nu
mber
of
crys
tals
Ly at ACCOS at 8Xo (pe/MeV)
Statistic on 100crystalsMean Value : 9.84 pe-/MeV
Standard deviation : 0.67 pe-/MeV
August 99 E.Auffray CMS/ECAL
Decay time
Distribution for 1000 crystals
% of emitted light in 100ns
0
20
40
60
80
100
120
90 91 92 93 94 95 96 97 98 99 100% of light in 100ns
August 99 E.Auffray CMS/ECAL
The slope of longitudinal transmission
between 340nm & 370nm
0
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300 350 400 450 500 550 600 650 700
Definition of the slope (340-370nm)
Tra
nsm
issio
n (
%)
Wavelength (nm)
Slope of the Linear fit of the longitudinal transmission
between 340nm & 370nm
0
5
10
15
20
25
0 0.5 1 1.5 2 2.5
LY loss after 1.5Gy versus the slope
LY
loss a
fter
1.5
Gy (
%)
Slope (T%/nm)
LY loss < 6%
Slope >1.5 (T %/nm)1964
1963
1958
August 99 E.Auffray CMS/ECAL
The slope of longitudinal transmission
between 340nm & 370nm
0
10
20
30
40
50
60
70
80
90
100
300 350 400 450 500 550 600 650 700
Definition of the slope (340-370nm)
Tra
nsm
issio
n (
%)
Wavelength (nm)
Slope of the Linear fit of the longitudinal transmission
between 340nm & 370nm
0
60
120
180
240
300
0 0.5 1 1.5 2 2.5 3
Slope (%/nm)
0.1% below 1.5%
August 99 E.Auffray CMS/ECAL
Radiation damage certification of Russian crystals
Irradiation of ingot’s top and bottom parts– All crystals– At Bogoroditsk– To control radiation hardness uniformity
High dose & dose rate side irradiation (induced absorption at all )– Sampling (20%)– At Bogoroditsk after March 99– To control absolute radiation hardness and uniformity
Transverse transmission along the crystal– All crystals– At Bogoroditsk and at CERN– To control doping uniformity
Longitudinal transmission band edge slope– All crystals– At Bogoroditsk and at CERN– To predict radiation hardness
High dose & dose rate side irradiation (induced absorption at all )– Sampling (20%)– At Geneva hospital (CERN)– To control absolute radiation hardness & uniformity
Low dose rate front irradiation (LY loss)– Sampling (20%)– At CERN (TIS)– To control radiation hardness in LHC conditions
Low dose rate side irradiation (transmission loss at ≠ )– Sampling (20%)– At CERN (X5)– To control radiation hardness uniformity
August 99 E.Auffray CMS/ECAL
Sampling irradiation tests
90
91
92
93
94
95
96
97
98
99
100
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
LY a
fter/L
Yb
efo
re (
%)
Dose (Gy)
also test at PSI
Batch 3 & 4
Front irradiation 0.15Gy/h
August 99 E.Auffray CMS/ECAL
Radiation Hardness
Lateral irrad., 500Gy, 240Gy/h
Front irrad., 1.5Gy, 0.15Gy/h
0
5
10
15
0 0.5 1 1.5 2 2.5 3
Induced absorption at 420nm (m-1)
86 Crystals
Mean value : 0.9m-1
Standard dev : 0.38m-1
0
10
20
30
40
50
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
LY loss (%)
Statistic on 141 crystalsMean Value : 2.96 %
Standard deviation 1.07%
August 99 E.Auffray CMS/ECAL
Status of crystal deliveryfrom Bogoroditsk (Russia)
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1000
Sep
Nov
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Mar
May
Jul
Sep
Nov
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May
Delivered crystals
Planning Delivered
0
10
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30
40
50S
ep
Nov
Jan
Mar
May
Jul
Sep
Nov
Jan
Mar
May
Rejected Crystals
Dimensions TransmissionLight Yield Decay timeSlope/Rad.hardness
1998 1999 2000
1000 crystals delivered28 May 1999
August 99 E.Auffray CMS/ECAL
Conclusion
•Ramping up in production rate according to plans•Continous improvement of the crystal characteristics from batch to batch :• Improvement of dimensions• Improvement of the transparency
(no more core defect)
• Exceptional rejection for bad radiation hardness
The results on first 1000 preproduction crystals
are very encouraging