Development of ultra-pure NaI(Tl) detectors for the COSINE-200 experiment B. J. Park, J. J. Choi, J. S. Choe, O. Gileva, C. Ha, A. Iltis, E. J. Jeon, D. Y. Kim, K. W. Kim, S. K. Kim et al. (10 more) Eur. Phys. J. C, 80 9 (2020) 814 Published online: 02 September 2020 DOI: 10.1140/epjc/s10052-020-8386-8