Search for double $\beta$-decay modes of ${}^{64}$Zn using purified zinc

Abstract

The production of ultra-pure raw material is a crucial step to ensure the required background level in rare event searches. In this work, we establish an innovative technique developed to produce high-purity (99.999%) granular zinc. We demonstrate the effectiveness of the refining procedure by measuring the internal contaminations of the purified zinc with a high-purity germanium detector at the Laboratori Nazionali del Gran Sasso. The total activity of cosmogenic activated nuclides is measured at the level of a few mBq/kg, as well as limits on naturally occurring radionuclides are set to less than mBq/kg. The excellent radiopurity of the zinc sample allows us to search for electron capture with positron emission and neutrinoless double electron capture of ${}^{64}$Zn, setting the currently most stringent lower limits on their half-lives, $T_{1/2}^{\epsilon {\beta }^{+}}>2.7\times 10^{21}\text{yr}$ (90% C.I.), and $T_{1/2}^{0\nu 2\epsilon }>2.6\times 10^{21}\text{yr}$ (90% C.I.), respectively.

References in corpus (5)

• \textsc{MaGe} - a {\sc Geant4}-based Monte Carlo Application Framework for Low-background Germanium Experiments
• Final result of CUPID-0 phase-I in the search for the ${}^{82}$Se Neutrinoless Double Beta Decay
• Background Model of the CUPID-0 Experiment
• First search for Lorentz violation in double beta decay with scintillating calorimeters
• First search for $2\epsilon$ and $\epsilon {\beta }^{+}$ decay of ${}^{174}$Hf

Cited by in corpus (2)

• Disentangling the sources of ionizing radiation in superconducting qubits
• ZnO-based scintillating bolometers: New prospects to study double beta decay of ${}^{64}$Zn