Transcript R&D of Some Scintillation Crystals at BGRI

2nd HHCAL workshop, Beijing, May 9, 2010
R&D on Scintillation Crystals
and Special Glass at BGRI
Mingrong ZHANG, Yuncheng GE
(Beijing Glass Reseach Institute)
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Contents
• Scintillation Crsytals Developed at BGRI
• Special Glass Developed at BGRI
– Low-resistivity Glass for MRPC
• Study on Eu-doped PbF2 Crystal for the
HHCAL Detector Concept
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Scintillation Crystals Researched
and Developed at BGRI
BGRI has studied synthetic crystals for half a century. In
the past twenty years more than ten kinds of scintillation
crystals have been developed.
• Fluorides: BaF2, BaF2:Ce, CeF3, CaF2:Eu
• Iodides: CsI:Tl, CsI:Na
• Oxides: PbWO4(PWO), Bi4Ge3O12(BGO)
• Chlorides: LaCl3:Ce
• Bromides: LaBr3:Ce, La(Br,Cl)3:Ce
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BaF2 Scintillation Crystal
BaF2 crystal is the first scintillation crystal developed at BGRI, which was
hoped originally to used for GEM detector at SSC, USA. Since 1996
BGRI has provided hundreds of large BaF2 crystals for nuclear physics
experiment projects.
Project/User
Period
TAPS/ Giessen Uiv,Germany
1996-2000
DANCE / LANL,USA
1997-2002
VEC/ VECC,India
2001-2002；2004-2006
4πγ Detector/ CIAE,China
2004-2006
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BaF2 crystal for 4πtotal absorption detector
at Chinese Institute of Atomic Energy (CIAE)
1472 cm3
1484 cm3
30 pieces
12 pieces
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Emssion spectrum
Alpha background
10#：419.2cps；12#：282.9cps
Energy resolution 12.8%
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Detecting Efficiency:
Time resolution
N=55016 for 137Cs 662keV
N= 36651 @1173keV, 36681@1332keV for 60Co
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CeF3 scintllation crystal
• BGRI developed CeF3 crystal initially for CMS at LHC by Jointing
with SIC (Shanghai Institute of Ceramics) in 1993-1995
• BGRI continues providing CeF3 crystals for discriminating n and γ
after that.
• Available maxium size
– Φ76×76 mm
Transmission spectra of 5mm CeF3 wafer
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CaF2:Eu Scintillation Crystal
241Am
Samples
Size (mm)
Φ20×2.0
7#
10#
Φ20×0.45
25.4×3.0×0.45
(59.6keV)
Channel
FWHM
Energy
resolution
p.e. yields
Notes
183.35
43.56
23.8%
7780
120.49
31.97
26.5%
5112
7T(top)
193.61
41.62
21.5%
8215
7B(bottom)
179.94
38.73
21.6%
7610
196.60
36.39
18.5%
8342
Decay times measured with Osillograph:
7T、7B、10-1、10-2，0.8-0.9ms
7T
7#
22
18
2.0
7B
Available size: more than 100 mm
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Tansmission, Excitaion and Emission Spectra of CaF2:Eu Crystal
No line-shaped emission of Eu3+ ions
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CsI:Tl Scintillation Crystal
• BGRI Developed CsI:Tl crystal in 1995-1997 by Jointing SIC for
BELLE at KEK,Japan and BaBar at SLAC,USA ,respectively
A unpolished CsI:Tl crystal
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Light output of CsI:Tl crystals of some
manufacturers at different time gates
Nonuniformity of CsI:Tl samples
along longitudinal direction: ≤4%
Higher light yield, faster decay and
better nonuiformity
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Transmission spectrum of CsI:Tl Crystal (Ф125×55 mm) produced recently
• Larger CsI:Tl crystal will be developed soon
Diemeter: ~ 400mm
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PWO Scintillation Crystal
• BGRI developed PWO crystal for CMS at LHC in 1996-2001
by collaborating IHEP,China and ETHZ, Switzerland.
As-grown ingots and Full-size (222×230×252mm) polished crystals
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Light yield and LY100/LY1000
30303000000790/
30303000000791/
30303000000792/
30303000000793/
30303000000794/
30303000000795/
30303000000796/
30303000000797/
30303000000798/
30303000000799/
Light Yield ly 100/1000 FNUF
13.2092
100 0.444735
13.38701
100 0.740469
13.61318
100 0.486111
14.57386 99.999799 0.34399
14.61634
100 0.785667
14.61172
100 0.664361
14.40189
100 0.264971
13.9384
100 0.315369
14.06109
100 0.402257
13.57327
100 0.187849
RNUF
0.487421
0.421873
0.344634
0.354776
0.646298
0.444478
0.308328
0.229429
0.469913
0.346003
longditudinal transmission of PWO crystals from
BGRI batch 1 measured longitudinally measured
with ACCOS RC CERN
Distribution of the Light Loss after 1.5Gy TIS for
10 BGRI crystals
Comparison of longditudinal transmission of
PWO crystals from Bogorodisk, SIC series 1&2,
BGRI
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LaX3:Ce (X=Cl,Br, or Cl+Br) Scintillation
Crystals
• LaCl3:Ce and LaBr3:Ce crystals have been studied at BGRI since 2003
and 2005, respectively.
• CeCl3-doped LaBr3 crystal, i.e. La(Br,Cl)3:Ce Crystal is found and
applied for a Chinese Patent by BGRI in 2007.
• LaCl3:Ce Crystal
La/CeCl3 Synthesis
Crystal Growth
Crystal Processing
Hermetic Sealing
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LaCl3:Ce Φ38×38mm
Alpha background: 51 cps, 1.18 c/s.cm3
Transmission Spectrum
Pulse-Height Spectrum
X-ray excited emission spectrum
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• La(Br,Cl)3:Ce (CeCl3-doped LaBr3) Crystal
385nm
Background:
4.3 cps
0.11 c/s/cc
X-ray ecited Emmission Spectrum
Φ40×30mm
Pulse-Height Spectra under 137Cs irradation
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Comparation of Scintillation properties of LaBr3:Ce
and La(Br,Cl)3:Ce crystals
Decay time（ns）
Photoelectron yield
(p.e./MeV)
rise
flat
decay
Energy
resolution
LaBr3: 0.9%CeCl3
11100
3.2
5.0
20.4
2.8%
LaBr3: 0.9%CeBr3
11200
4.3
7
25.7
3.0%
LaBr3: 4%CeCl3
11000
2.5
/
16.4
3.0%
LaBr3: 4%CeBr3
10800
2.1
/
17.0
3.1% *
Crystals
* Sample was not sealed well.
La(Br,Cl)3:Ce crystal has similar scintillation
properties to LaBr3:Ce crystal, but better
performance-price ratio for CeCl3 is cheaper
than CeBr3.
Availabe Maxium Size: Φ40×50mm
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Comparisions of LaCl3:Ce crystal and LaBr3:5%CeCl3 crystal
grown by BGRI with NaI:Tl crystal
Crystal
Size /mm
Pulse Height
/ Channel
Relative
Pulse Height
Energy
Resolution
Decay
time
La(Br,Cl)3:Ce
Φ40×30
930
163
2.9%
17ns
LaCl3:Ce
Φ38×38
503
90
3.5%
26ns
NaI:Tl
Φ38×38
570
100
6.2%
Note: The data listed in the above table were obtained by measuring three
crystals with same PMT and same gain setting.
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Special Glass Developed at BGRI
BGRI has studied glass for more than 50 years. And
more than twenty kinds of special glass have been
developed, which include:
• Colorless glass
• Colored glass
• Irradiation-hard glass
• low-resistivity glass
• other special glass
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R&D of Low Resistivity Glass For MRPC
• BGRI began R&D of low-resistiviy glass in 2007 at the help of Tsinghua University
Low-resistivity glass is promising materials for Multi-gap Resistive Plate
Chamber (MRPC) for measuring TOF of high–energy particles in relativistic
heavy ions physics.
Name
Producer
Electric resistivity
Moscow glass
Budker Institute of Nuclear PhysicsNovosibirsk, Russia
1011 Ω·cm
Schott, Germany
1011 Ω·cm
Prague glass
Phyiscs Institue, Czech
1011 Ω·cm
Sem. glass
BGRI & Tsinghua University, China
1010 Ω·cm
Schott S8900
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The temeperature dependence of electric resistivity of our glass
Sem. glass
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Comparisions of MRPCs made of different materials in CBM
RPC type
Material
Detecting efficiency
Time Resolution
Rate Capability
Pad MRPC
sem. glass
95 %
75 ps
not meas.
Ceramic MRPC
ceramic
95 %
110-140 ps
500 kHz/cm2
Pad mini-RPC
ultrathin glass
75% (1 Gap)
75-100 ps
1,5 kHz/cm2
narrow strip MRPC
float glass
85 %
50 ps
not meas.
Wide Strip MRPC
sem. glass
95 %
75 ps
20 kHz/cm2
Wide Strip MRPC
float glass
95 %
65 ps
not meas.
Wide Strip MRPC
float glass
95 %
75 ps
not meas.
See: “The CBM Time-of-Flight Wall”, X Workshop on Resistive Plate Chambers
and related Detectors, February 9-12, 2010, GSI, Darmstadt, Germany．
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BGRI & Tsinghua University
Large glass sheet (500×500mm) with the 1010Ω·cm resistivity was
manufactured sucessfully at BGRI.
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Some Results of Eu-doped PbF2 crystal
for the HHCAL Detector Concept
Raw materials
Eu Content
Growth technique
PbF2:Eu Crystal
CaF2:Eu crystal
PbF2
CaF2
A mixture of EuF3 and EuF2
1#: 500ppm
2#: 1%
200-3000 ppm
graphite crucible + vacuum furnace
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Transmission spectra
Pulse Height Spectra under 137Cs radiation
No obvious photoelectron signal was detected by PMT!
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1#
Emission Spectra
under 365nm excitation
2#
No obvious wide-band emission,
different from that of CaF2:Eu crystal
Maybe Eu2+ ions donot exist in
PbF2 crystal stably?
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• BGRI is very interested in the material
development for the HHCAL detector
concept, and is expected to contribute to
this world-wide effort.
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Thanks for Listening
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