Journal of Radioanalytical and Nuclear Chemistry

, Volume 317, Issue 3, pp 1329–1332 | Cite as

Reduction of the radioactivity in sodium iodide (NaI) powder by recrystallization method

  • KeonAh Shin
  • Olga Gileva
  • Yeongduk Kim
  • Hyun Su Lee
  • HyangKyu ParkEmail author


The COSINE experiment is searching for dark matter using ultra-low background NaI scintillating crystals. In order to reduce the internal contamination of the initial NaI powder to grow NaI crystals, NaI powder samples with different purities were purified by fractional recrystallization using de-ionized water. The concentrations of the main radioactive elements, K, Pb, Th, and U, which are major backgrounds for the dark matter search, were reduced to the level required for the experiment. Further, the concentrations of other impurities, e.g., Ba, Ca, Cr, and Fe, were also reduced, which is important to realize good quality NaI crystals.


Dark matter Fractional recrystallization Radioactive impurity Ultralow-background NaI crystal 



We thank J.S. Choi for ICP-MS measurements. This research was funded by the Institute for Basic Science (Korea) Under Project Code IBS-R016- A1. HyangKyu Park was supported by a Korea University Grant.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2018

Authors and Affiliations

  1. 1.Center for Underground PhysicsInstitute for Basic ScienceDaejeonKorea
  2. 2.Department of Accelerator Science, Graduate SchoolKorea UniversitySejongKorea

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