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ID 116868
Author
Kanemitsu, Y. Tokushima University
Hirata, S. Tokushima University|Otsuka Pharmaceutical Factory
Chernyak, D. University of Alabama
Hazama, Ryuta Osaka Sangyo University
Ikeda, H. Tohoku University
Imagawa, K. I.S.C. Lab.
Ishiura, H. Kobe University
Ito, H. The University of Tokyo
Kisimoto, T. Osaka University
Kozlov, A. National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute)
Takemoto, Y. The University of Tokyo|Kavli Institute for the Physics and Mathematics of the Universe
Yasuda, K. I.S.C. Lab.
Ejiri, Hiroyasu Osaka University
Hata, K. Tohoku University
Iida, T. University of Tsukuba
Inoue, K. Tohoku University|Kavli Institute for the Physics and Mathematics of the Universe
Koga, M. Tohoku University|Kavli Institute for the Physics and Mathematics of the Universe
Nakamura, K. Tohoku University|Kavli Institute for the Physics and Mathematics of the Universe|Butsuryo College of Osaka
Shima, T. Osaka University
Umehara, S. Osaka University
Yoshida, S. Osaka University
Content Type
Journal Article
Description
Highly radiopure NaI(Tl) was developed to search for particle candidates of dark matter. Optimized methods were combined to reduce various radioactive impurities. 40K was effectively reduced by the recrystallization method. The progenies of the decay chains of uranium and thorium were reduced by appropriate resins. The concentration of natural potassium in NaI(Tl) crystal was reduced to 20 ppb. Concentrations of alpha-ray emitters were successfully reduced by appropriate resin selection. The present concentrations of the thorium series and 226Ra were 1.2±1.4μBq/kg and 13±4μBq/kg, respectively. No significant excess in the concentration of 210Pb was obtained, and the upper limit was 5.7 μBq/kg at 90% CL. The achieved level of radiopurity of NaI(Tl) crystals makes the construction of a dark matter detector possible.
Journal Title
Progress of Theoretical and Experimental Physics
ISSN
20503911
Publisher
The Physical Society of Japan|Oxford University Press
Volume
2021
Issue
4
Start Page
043F01
Published Date
2021-02-16
Rights
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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language
eng
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departments
Science and Technology