High-Purity Zinc for Low-Background Experiments

Abstract

A process has been developed for the preparation of high-purity granulated zinc for the growth of Zn 82 Se scintillator crystals intended for investigation of neutrinoless double beta decay, 2β(0ν), of the 82 Se isotope in the CUPID-0 experiment. We have determined the chemical and isotopic compositions of highpurity zinc prepared by this process and assessed its radionuclide purity. The background spectrum of the high-purity zinc, measured with a germanium detector, showed no peaks of natural 40 K, 60 Co, or 137 Cs radionuclides or ones from the uranium-thorium decay series. We have noticed an increased activity of the 54 Mn, 56 Со, 57 Со, 58 Co, and 65 Zn nuclides, resulting mainly from the exposure to cosmic rays.