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Growth and Scintillation Properties of TwoInch-Diameter SrI2(Eu) Single Crystals Yasuhiro Shoji, Shunsuke Kurosawa, YUUI YOKOTA, Shoki Hayasaka, Kei Kamada, Masao Yoshino, Akihiro Yamaji, Valery Chani, Yuji Ohashi, Shiro Sakuragi, and Akira Yoshikawa Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.7b01044 • Publication Date (Web): 21 May 2018 Downloaded from http://pubs.acs.org on May 21, 2018
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Crystal Growth & Design
List of Figures Fig. 1. View of the furnace (left) and schematic diagram of SrI2(Eu) single crystal growth(right) Fig. 2. Position of the thermocouple used for measuring the seeding temperature (left) and the position of the thermocouple to verify the variation of the growth rate along the boule (right). Fig. 3. The distribution of Eu2+ along the radial and growth directions. Fig. 4. View of the packaged SrI2(Eu) specimen (diameter = length = 2 in.) under normal (left) and ultraviolet light (right). Fig. 5. SrI2(Eu) crystal grown using the optimized conditions (left) and the corresponding temperature profile on the crucible bottom. Temperature measurements were performed using a thermocouple, as shown in Fig. 2 (left). Fig.6. The corresponding temperature profile on the crucible bottom, middle and top using a thermocouple, as shown in Fig. 2 (right). Fig.7. View of the 5mm cubic from the grown SrI2(Eu) (left), and impurity layer (middle) and raw material (right) for impurity analysis. Fig.8. Effect of the surface treatment of the 10 mm cubic SrI2(Eu) specimen on their pulse height spectra. Fig. 9. View of the packaged SrI2(Eu) specimen (diameter = length = 2 in.) under normal (left-top) and ultraviolet (left-bottom) light and the pulse height spectra of this specimen and Tl-doped NaI. Fig. 10. Scintillation decay curve of an SrI2(Eu) single crystal (diameter = length = 2 in.) Table.1. Analysis of impurities in each sample.
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RF coil
Carbon crucible
raw material
Seed Crystal growth Fig. 1. View of the furnace (left) and schematic diagram of SrI2(Eu) single crystal growth(right)
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Crystal Growth & Design
K-thermo couple
Fig. 2. Position of the thermocouple used for measuring the seeding temperature (left) and the position of the thermocouple to verify the variation of the growth rate along the boule (right).
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wt (%) 0.500
RD-R
0.480
RD-C
0.460
RD-L
0.440 0.420 0.400 0.380
0.360 0.340 0.320 0.300 0
20
40
60
Length (mm)
Fig. 3. The distribution of Eu
2+
along the radial and growth directions.
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80
100
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Crystal Growth & Design
Fig. 4. View of the packaged SrI2(Eu) specimen (diameter = length = 2 in.) under normal (left) and ultraviolet light (right).
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bottom
Temp(℃)
Growth time (Min)
Fig. 5. SrI2(Eu) crystal grown using the optimized conditions (left) and the corresponding temperature profile on the crucible bottom. Temperature measurements were performed using a thermocouple, as shown in Fig. 2 (left).
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Crystal Growth & Design
Temp(℃) 700 600 TC：Top
500
TC：Middle TC：Bottom
400
Start cooling 300 200 100 0
0
2000
4000
6000
8000
10000
12000
14000
16000
Growth time(min)
Fig.6. The corresponding temperature profile on the crucible bottom, middle and top using a thermocouple, as shown in Fig. 2 (right).
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Fig.7. View of the 5mm cubic from the grown SrI2(Eu) (left), and impurity layer (middle) and raw material (right) for impurity analysis.
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Crystal Growth & Design
A: Chemical Etching
B: Mirror polish
C: Polishing type X
Fig.8. Effect of the surface treatment of the 10 mm cubic SrI2(Eu) specimen on their pulse height spectra.
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Fig.9. View of the pulse height spectra of packaged SrI2(Eu) specimen (diameter = length = 2 in.) and Tl-doped NaI.
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Crystal Growth & Design
Fig. 10. Scintillation decay curve of an SrI2(Eu) single crystal (diameter = length = 2 in.)
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Table.1. Analysis of impurities in each sample. Samples Grown SrI2(Eu) Impurity layer Raw material
Elemental analysis (ppm) Ca Ba Ce
O
C
Na
Mg
0.526
0.0014
