High-pure zinc for growing Zn⁸²Se scintillation crystals

A process has been developed to produce high-purity granular zinc for growing Zn⁸²Se scintillation crystals designed to study the neutrinoless double beta decay (0ν2β) of the selenium isotope ⁸²Se in the CUPID-0 experiment. The chemical and isotopic compositions of high-purity zinc were studied and its radioactive purity was evaluated. At a level less than mBq·kg^-1 in the background spectrum of high-purity zinc, measured by a germanium detector, no peaks were observed for natural radionuclides ⁴⁰K, ⁶⁰Co, ¹³⁷Cs and the uranium-thorium decay chain. An increased activity of such nuclides as ⁵⁴Mn, ⁵⁶Co, ⁵⁷Co, ⁵⁸Co and ⁶⁵Zn, formed mainly due to cosmogenous effects, was noted. (author)