High-efficiency recovery of 82Se from enriched Zn82Se scintillating bolometer crystals

Abstract

Abstract As experiments searching for neutrinoless double beta decay push into the inverted hierarchy, enriched isotope target masses of hundreds of kilograms are required. Due to unavoidable losses throughout the entire production chain, the recovery of expensive enriched material used in crystal-based experiments should be given special attention. The CUPID-0 experiment using Zn82Se scintillating bolomoters provides a unique opportunity at the 10-kg-scale to test a recovery process for enriched 82Se. We present a multi-stage, high-yield method consisting of wet chemistry and vacuum distillation. The chemical purity, isotopic abundance, and radiopurity is demonstrated to be preserved after the 82Se extraction with recovery efficiency no less than 86.4% (that potentially can be higher than 94.7%) and chemical purity of 99.999%.