Enriched Zn$^{100}$MoO$_4$ scintillating bolometers to search for $0 \nu 2\beta$ decay of $^{100}$Mo with the LUMINEU experiment

TL;DR

This paper reports on the development and testing of enriched ZnMoO$_4$ scintillating bolometers for neutrinoless double beta decay searches, demonstrating high performance and promising future sensitivity.

Contribution

First successful growth of enriched $^{100}$Mo zinc molybdate crystal boule with high yield and low losses, and its validation as an effective bolometric detector.

Findings

Enriched ZnMoO$_4$ crystals achieved high detection performance.

The production process had high yield and low material loss.

Results support future sensitive neutrinoless double beta decay experiments.

Abstract

The LUMINEU project aims at performing a demonstrator underground experiment searching for the neutrinoless double beta decay of the isotope $^{100}$Mo embedded in zinc molybdate (ZnMoO$_4$) scintillating bolometers. In this context, a zinc molybdate crystal boule enriched in $^{100}$Mo to 99.5\% with a mass of 171 g was grown for the first time by the low-thermal-gradient Czochralski technique. The production cycle provided a high yield (the crystal boule mass was 84\% of initial charge) and an acceptable level -- around 4\% -- of irrecoverable losses of the costy enriched material. Two crystals of 59 g and 63 g, obtained from the enriched boule, were tested aboveground at milli-Kelvin temperature as scintillating bolometers. They showed a high detection performance, equivalent to that of previously developed natural ZnMoO$_4$ detectors. These results pave the way to future sensitive searches based on the LUMINEU technology, capable to approach and explore the inverted hierarchy region of the neutrino mass pattern.