24-28 February 2020
Budker Institute of Nuclear Physics
Asia/Novosibirsk timezone

A Facility for mass production of ultra-pure NaI powder for the COSINE-200 experiment

Not scheduled
Budker Institute of Nuclear Physics

Budker Institute of Nuclear Physics

11, akademika Lavrentieva prospect, Novosibirsk, Russia
Board: 57
Poster Instrumentation for Astroparticle and Neutrino physics


Ms Keonah Shin (CUP, IBS)


The COSINE experiment aims to reproduce DAMA/LIBRA’s observation of an annual modulation signal that can be interpreted as interactions of WIMPs (Weakly Interacting Massive Particles) dark matter. Ultra-low background NaI(Tl) crystal detectors are being developed for the next-phase experiment, COSINE-200. For the COSINE-200 experiment, all steps in the low-background detector production process, including the purification of ultra-pure powder, the growing of crystal, and the detector assembly, are being carefully developed. In this presentation, we discuss the purification of the ultra-pure powder, including the development of an instrument based on recrystallization for its mass production in our laboratory at the Center for Underground Physics, Daejeon, Korea. The COSINE-200 experiment’s goals require in total at least 500 kgs of NaI powder with contaminations from potassium (K) below 20 ppb and Pb-210 below 0.1 mBq/kg for the production of a 200 kg detector. To satisfy these requirements, a special clean facility that purifies NaI powder by means of fractional recrystallization from a water solution has been constructed. This facility consists of a dissolving tank, a recrystallization tank, a filter housing and a vacuum biconical dryer. The Maximum initial powder charge capacity is 70 kg and its recovery rate is typically ~45%. In normal operation, a single batch produces 30 kg of purified NaI powder in five days. To validate the purity of the produced product, the concentrations of K, Pb, Sr, Ba, Th and U were measured by ICP-MS method and these confirmed sufficient reduction of K concentration to below 20 ppb and those of all other radio-impurities as well. Details of the mass-production of purified NaI powder for the COSINE-200 experiment will be presented.

Primary author

Ms Keonah Shin (CUP, IBS)


Prof. Hyang Kyu Park (Department of Accelerator Science, Korea University) Dr Hyun Su Lee (CUP, IBS) Mr Junseok Choe (CUP, IBS) Dr Moo Hyun Lee (Center for Underground Physics, Institute for Basic Science (IBS)) Dr Olga Gileva (Center for Underground Physics, IBS, Dajeon, KOREA) Dr Yeongduk Kim (CUP, IBS)

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