Transcript Como Invited Talk

Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Lead Tungstate Crystals for the CMS
Electromagnetic Calorimeter at the LHC
Ioan Dafinei
I.N.F.N. Sezione di Roma, Rome ITALY
(on behalf of CMS ECAL Collaboration)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Index
Villa Olmo, Como 15-19 October 2001
1.
Introduction
2.
PWO General Properties
3.
-
Luminescence Spectrum
-
Scintillation characteristics
-
Radiation hardness
PWO for ECAL-CMS
-
R&D Short Review
-
Requisites & Qualification Parameters
-
Regional Centers
4.
Preproduction Crystal Properties
Present Status
5.
Recent Developments in PWO Crystal Growth Technology
6.
Conclusions
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Introduction
Villa Olmo, Como 15-19 October 2001
Requirements for scintillators to be used for ECAL construction
high stopping power
small X0
high granularity
small Rm
ECAL-CMS
high energy resolution
LHC
Bunch separation 25 ns
large LY
short dead time
Luminosity 1034 cm-2·s-1
technological requirements
high density and high Z
fast
radiation hard
• mechanical ruggedness
• chemical stability
• uniformity of properties
• low price
emission spectrum overlapping
with spectral sensitivity of
commonly used photodetectors
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Introduction
Villa Olmo, Como 15-19 October 2001
40
PWO properties
PWOusers
PWO+Other
total
PbWO4 (PWO)
Studied as scintillator since 1979
r (g/cm3)
8.26
X0 (cm)
0.89
Rm (cm)
2.2
t (ns)
15
lemission
420
n@ lemission
2.29
LY
2%
LYtemp.coeff.
SCINT Conferences
20
0
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
ArticleStatistics.QPC
-2%/°C
Workshop on
tungstate crystals
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
PWO General Properties
Villa Olmo, Como 15-19 October 2001
PWO Crystal Growth
Bogoroditsk
Shanghai Institute
Techo Chemical
of Ceramics,
Plant,
China
Russia
seed
1123°
1100
Czochralski method
Liquid
1000
970°
935°
915°
37%
900
grown
crystal
66.5%
800
PbO
20
1:1
2:1
700
740°
730°
16.5%
PWO3
40
PWO4
molten PWO
Chang, 1971
60
mole %
80
WO3
RF heating
Bridgman method
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
PWO General Properties
Villa Olmo, Como 15-19 October 2001
Luminescence Spectrum
1.2
PWO1185
PWO1180
PWO1168
295 K
blue component
green component
intensity (a.u.)
1
Pb2+
0.8
0.6
WO42-
c
0.4
0.2
0
300
a
400
500
wavelength (nm)
600
700
Luu m
L
mS
Spp ec tr
traa--b
B l+G
gr
u
e ee.n
.Q
Q. P
Q
PC
P
CC
(MoO4) 3c
WO43(WO6) 6-
c
a
a
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
PWO General Properties
Villa Olmo, Como 15-19 October 2001
Scintillation Characteristics
Photoluminescence decay
10
10
10
10
10
10
emision@400 nm
emision@500 nm
laser pulse
-1
decay data
3exp fit
true background
-3
-4
10
10
-6
-8
10
-7
10
-6
lexc=308 nm (XeCl excimer laser)
10
-5
time (s)
3
a=100·(Iss/Itot) (%)
Itot
-5
10
L u mL a se r E x c .Q P C
Spectrally unresolved scintillation
-2
2
counts per channel
intensity (a.u.)
10
0
Iss
10
0
D e c a y I n te g r a l . Q P C
50
100
150 200
tim e (ns)
250
300
1
350
I(t)=0.5·exp(-t/3ns)+0.07·exp(-t/12ns)+0.008·exp(-t/102ns)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
PWO General Properties
Villa Olmo, Como 15-19 October 2001
1400
1200
light yield (a.u.)
1000
300
0
250
-1
200
-2
150
-3
100
-4
50
-5
temp.coeff.(%/°C)
light yield (a.u.)
Scintillation Characteristics
-40 -20 0 20 40 60
temperature (°C)
800
600
400
200
0
-200
a20°C = -1.98%/°C
I.Dafinei, Mat.Res.Soc. Vol.348(1994), p.99
-150
-100
-50
0
50
temperature (°C)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
PWO General Properties
Radiation Hardness
80
•light production is not affected
60
295 K
undoped
3
-1
induced absorption (m )
transmission (%)
•creation of color centres is
quenched by appropriate doping
La-doped
40
20
undoped
2
1
La-doped
0
300
500
70 0
w avelength (nm )
90 0
0
300
Rad Har d .QP C
400
500
600
700
800
wavelength (nm)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
R&D Short Review
Villa Olmo, Como 15-19 October 2001
• 1992 : Crystal2000 Conference
• 1994 : choice of PWO for CMS-ECAL
• 1994-1998 : R&D phase
1995
1998
Transmission (%)
100
80
60
Theoretical transmission
'98 crystal
40
'95 crystal
20
0
300 350 400 450 500 550 600 650 700
Wavelength (nm)
• 1998-2000 : Pre-Production of 6000 crystals
• 2001 : Start of the Production
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
R&D Short Review
Goals of Pre-production Activity
For Producer :
Increase the rate of production
Improve the crystal quality and homogeneity of properties
For CMS-ECAL community
Setting up the Regional Centres
Installation of Automatic Crystal Control System (ACCOS)
(machines designed to make the full characterisation of 30 crystals in 7 hours)
All the 6000 crystals have been measured on ACCOS at CERN
800 re-measured on ACCOR at Rome (ACCOS-ACCOR intercalibration)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Requisites & Qualification Parameters
Qualification parameters
Light Yield
LY(x)= a · x+b
LY@8X0 =7.5·a+b
FNUF =100·(-0.89·a)/(11.5·a+b)
• LY@8X0  8 pe/MeV at 18°C
• -0.35 %/X0  FNUF  +0.35 %/X0
• LY(100ns)/LY(1ms) > 90%
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Requisites & Qualification Parameters
Qualification parameters
Transmission
T=p2·exp(-(p3)/w-exp((p0-w)·p1))
LT
Transmission (%)
80
TT
•LT360nm  25%
•LT420nm  55%
•LT620nm  65%
•LTslopeinflection > 3%/nm
 dlTT=50%  3nm
TT
60
LT
40
20
0
300
PWO1713_Ro.QPC
400
500
600
wavelength (nm)
LT
15
35
55
75
95
115
135
155
175
195
215
700
Check general quality and radiation resistance
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Requisites & Qualification Parameters
Qualification parameters
Dimensios
!
•dimensions within +0.00 mm , -0.10 mm of nominal values
•planarity for all faces within 0.02 mm
•chamfers between 0.3 mm and 0.7 mm
•polished faces with roughness < 0.020 mm
•unpolished face with roughness = 0.350 mm
ECAL-CMS
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
CERN Lab.27 Regional Center
ACCOCE
http://cmsdoc.cern.ch/cms/ECAL/html/wp/rc/
CERN Lab.27
EP-CMA
Light yield uniformity
Transmission
Dimensions
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
Rome, Italy Regional Center
Dark room
temperature :
20±0.5°C rel.
humidity:
50±10%
http://www.roma1.infn.it/exp/cms/
ACCOR
Dimensions
Casaccia
Coord3 S.p.A.
Capacity:
35 crystals/run
1 run time:
approx. 10
hours
Light yield uniformity
Co60
LED
Transmission
PM
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
ACCOS-ACCOR Intercalibration
LY>8pe/MeV
Measure 2-3 pe !
-0.35<FNUF(%/Xo)<+0.35
sR-C=0.8pe/MeV
sR-C=0.19%/Xo
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
ACCOS-ACCOR Intercalibration
LT@360nm
LT@420nm
CernLT@420
CernLT@360
50
40
30
20
CernLT@620
75
60
70
LT@620nm
80
75
65
70
60
60
65
65
10
0
0
10 20 30 40 50 60
RomeLT@360
sR-C=1.4%
65
70
75
RomeLT@420
sR-C=0.8%
70
75
80
RomeLT@620
sR-C=0.5%
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
359
357
353
349
LT slope@inflection
4
3.5
Rad hard check
3
4
2.5
2
345
345
349
353
357
Rome
2
2.5
3
3.5
4
Rome S@infl (%/nm)
sR-C=0.15%/nm
Roma TTsp (nm)
Cern
Inflection Wavelength
Cern S@infl (%/nm)
ACCOS-ACCOR Intercalibration
TT spread at 50%
3.5
3
2.5
2
1.5
1
0.5
0
0 0.5 1 1.5 2 2.5 3 3.5 4
Cern TTsp (nm)
sR-C=0.15%/nm
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Regional Centers
Villa Olmo, Como 15-19 October 2001
ACCOS-ACCOR Intercalibration
AR
230.5
Statistics made
on 373 Xtals
230
BF
CR
CF
229.5
229.5
230.0
L@CERN (mm)
230.5
22.8
BF
22.2
CF@Roma (mm)
AF
AF@Roma (mm)
21.75
BF@Roma (mm)
L@Roma (mm)
BR
AF
L
21.5
21.50
21.75
AF@CERN (mm)
22.6
CF
22.0
21.8
21.6
22.4
22.40
22.60
BF@CERN (mm)
22.80
21.6
21.8
22.0
22.2
CF@CERN (mm)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Crystal Properties
Villa Olmo, Como 15-19 October 2001
10
batch 1
Mean: 61.88%
StDev. : 7.5%
8
Number of crystals
100
90
80
70
60
50
40
30
20
10
0
300 350 400 450 500 550 600 650 700
Wavelength (nm)
6
4
2
0
batch 8
30
35
40
45
50
55
60
65
Transmission at 420nm (%)
70
75
80
70
75
80
70
75
250
Mean: 69.01%
StDev. : 1.59%
200
150
100
1400
50
6000 crystals
1200
0
no.of Xtals
1000
30
35
40
45
50
55
60
65
Transmission at 420nm (%)
150
800
batch 14
55%
600
Mean: 70.07%
StDev. : 1.46%
100
400
200
0
50
30
35
40
45
50
55
60
65
70
Transmission at 420nm (%)
75
80
0
30
35
40
45
50
55
60
Transmission at 420nm (%)
65
80
11.04.01
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Pre-Production Crystal Properties
Pre-Production in China
18
16
# crystals
14
Transmission characteristics
12
10
8
6
4
40
2
35
0
30
# crystals
0 10 20 30 40 50 60 70 80
LT@360nm (%)
16
25
20
15
10
14
5
# crystals
12
0
10
Statistics made
on 100 crystals
8
6
4
0.1
1.1
2.1
3.1
Slope@infl (%/nm)
2
20
0
45
40
18
16
14
# crystals
0 10 20 30 40 50 60 70 80
LT@420nm (%)
12
10
8
6
35
4
# crystals
30
2
25
0
20
0.2 2.2 4.2 6.2 8.2 10.2
TTspread@50% (nm)
15
10
5
0
0 10 20 30 40 50 60 70 80
LT@620nm (%)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Pre-Production Crystal Properties
Batch 1 to 7 <Ra> depolished face +0.2m
500
400
350
LY@8X0
FNUF
300
250
300
200
150
200
100
100
50
0
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
LY@8X0 (pe/MeV)
-1.5
-1
-0.5
0
0.5
1
1.5
2
NuF Front (%/Xo)
Batch 8 to 14 <Ra> depolished face +0.39m
1400
1200
1200
LY@8X0
FNUF
1000
1000
800
800
600
600
400
400
200
200
0
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
LY@8X0 (pe/MeV)
-1.5
-1
-0.5
0
0.5
1
1.5
2
NuF Front (%/Xo)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Crystal Properties
Villa Olmo, Como 15-19 October 2001
Pre-Production in China
Light production characteristics
Statistics made
on 100 crystals
LY@8X0 (ACCOS measured)
35
30
25
# crystals
20
15
10
5
0
0
2
4
6
8
10
12
14
16
LY (p.e./MeV)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Crystal Properties
Villa Olmo, Como 15-19 October 2001
Front irrad., 1.5Gy, 0.15Gy/h
LYloss=(LY0-LYirr)/LY0 (%)
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Crystal Properties
Villa Olmo, Como 15-19 October 2001
10
StDev : 1.21%
Mean : 3.39%
N = 32 Xtals
8
batch 1
6
Front irrad., 1.5Gy, 0.15Gy/h
4
2
100
Statistics on 368 crystals
Mean : 2.45 %
StDev : 1.06%
0
0
20
60
40
20
Rejected for LT@350nm < 10%
Rejected for LTslope < 1.5%/m
80
0
1
2
3
4
5 6 7 8
LY loss (%)
N = 33 Xtals
16
9
10
StDev : 0.9%
Mean : 1.92%
batch 8
12
8
4
0
0
1
2
3
4
20
5 6 7
LY loss (%)
N = 19 Xtals
16
8
9
10
StDev : 1.21%
Mean : 0.92%
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 (%)
batch 14
12
8
4
0
0
1
2
3
4
5 6 7
LY loss (%)
8
9
10
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Crystal Properties
Villa Olmo, Como 15-19 October 2001
Pre-Production in China
Radiation hardness characteristics
Change of total light output during front
irradiation at 0.15 Gy/h data for 21 crystals
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Pre-Production Results
Villa Olmo, Como 15-19 October 2001
Sept. 1998 to Dec. 2000
6000 Crystals produced by BTCP
1000
50
Planning Delivered
Dimensions
Transmission
Light Yield
Decay time
Slope/Rad.hardness
dic-00
set-00
giu-00
mar-00
dic-99
set-99
Improved
giu-99
mar-99
dic-98
set-98
Increased
yield
production rate
dic-00
0
set-00
0
giu-00
10
mar-00
200
dic-99
20
set-99
400
giu-99
30
mar-99
600
dic-98
40
set-98
800
Xtals quality
stability of parameters
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Production Schedule
Started in 2001
Present status :
•6000 preproduction crystals
•2000 production crystals
To be produced before end 2004 :
•56000 crystals for Barrel
•16000 crystals for Endcaps
increased productivity
is needed
New crystal development :
Ingot diameter increase
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Recent Developments
Crystal Growth Technology Steps
Barrel
Endcap
Barrel
32 mm
44 mm
65 mm
1996
1999
End 2000
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Recent Developments
PWO crystals made in BTCP Bogoroditsk
F = 32 mm
F = 65 mm
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Recent Developments
Large PWO crystals made in BTCP Bogoroditsk
scintillation characteristics
A. N. Anenkov et all, Scint2001 Conference
time (ns)
%
30.0
80.3
50.0
89.9
100.0
96.4
300.0
99.3
1000.0
99.9
1525.5
99.9
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Recent Developments
Large PWO crystals made in BTCP Bogoroditsk
radiation hardness
A. N. Anenkov et all, Scint2001 Conference
longitudinal uniformity
saturation dose
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Recent Developments
Large PWO crystals made in BTCP Bogoroditsk
A. N. Anenkov et all, Scint2001 Conference
radiation hardness
radial uniformity
center
side
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Recent Developments
Villa Olmo, Como 15-19 October 2001
Large PWO crystals made in BTCP Bogoroditsk
radiation hardness
Transmission (%)
100
PWO 7365 1st irradiation at the Geneve Hospital
80
60Co
430 Gy
60
1i1
1irr1
Irr1 + 20'
Irr1 + 40'
Irr1 + 24h
40
20
0
300
350
400
450 500 550 600
Wavelength (nm)
650
700
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
New vs Old Technology
60
N = 300
Mean: 31.36%
StDev : 3.3%
LT@360
50
40
30
Batch P2 from CERN/ISTC
production contract #1718
was used to compare:
– 260 barrel crystals produced
with the standard technology
– 40 barrel crystals produced
with the new technology
20
10
0
0
5 10 15 20 25 30 35 40 45 50 55 60 65 70
Transmission at 360nm (%)
140
LT@420
120
100
N = 300
Mean: 69.91%
StDev : 0.85%
80
60
40
20
0
30
35
40
45 50 55 60 65 70
Transmission at 420nm (%)
75
80
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
New vs Old Technology
Villa Olmo, Como 15-19 October 2001
LT slope@inflection
140
N = 300 crystals
120
80
N = 300 crystals
250
Mean : 3.30%/nm
StDev : 0.06%/nm
100
LY@8X0
300
Mean : 9.1 pe/MeV
StDev : 0.57 pe/MeV
200
150
60
40
100
20
50
0
0
0
1
2
3 4 5 6 7 8 9
Slope@inflection (%/nm)
10
5
6
7
8 9 10 11 12 13 14
Light Yield (pe/MeV)
260 barrel crystals produced
with the standard technology
40 barrel crystals produced
with the new technology
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
New vs Old Technology
Front irrad., 1.5Gy, 0.15Gy/h
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Conclusions
• Present status of physics and technology of scintillating materials shows that
the CMS Collaboration decision to use PWO crystals for the ECAL construction
was the best possible choice
• Success of the R&D phase
– Increase of the production rate
– good quality crystals
– uniform optical properties
• Technology for ingots up to 65mm
diameter is now well under control
• The possibility to further increase the as
grown PWO diameter and to apply this
approach to endcap crystals is realistic
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY
Advanced Technology and Particle Physics
Villa Olmo, Como 15-19 October 2001
Conclusions
Ready to Construct the CMS-ECAL
CERN Lab.27
EP-CMA
&
Casaccia
1st module of 400 crystals build in 2001 for ECAL
Ioan Dafinei
Regional Centre ECAL-CMS Rome ITALY