First test of an enriched $$^{116}$$ 116 CdWO $$_4$$ 4 scintillating bolometer for neutrinoless double-beta-decay searches

A S Barabash,A S Zolotarova,E Olivieri,S Marnieros,D V Poda,V Novati,C Nones,S I Konovalov,M Mancuso,V I Tretyak,V I Umatov,A Giuliani,F A Danevich,P De Marcillac,Y Gimbal-Zofka,V N Shlegel

doi:10.1140/epjc/s10052-016-4331-2

Abstract

For the first time, a cadmium tungstate crystal scintillator enriched in $^{116}$Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ~82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated a high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV $\gamma$ energy range), a powerful particle identification capability and a high level of internal radiopurity. These results prove that cadmium tungstate is an extremely promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification).

Highlights

In contrast with the two-neutrino mode (2ν2β), experimentally observed in eleven isotopes with half-lives in the range 1018–1024 years and allowed in the Standard Model, the 0ν2β decay has not been detected yet
The energy resolution of the filtered baseline noise (FWHMBsl ) and the amplitude of the signal (SN T D) for a given deposited energy were estimated for each data set (1–3 days of measurements)
Taking into account the expected high light yield2 of cadmium tungstate at low temperatures (e.g., ∼17 keV/MeV [38]), we have chosen a light detector with a relatively modest performance, as it is visible from Table 1

Summary

Introduction

In contrast with the two-neutrino mode (2ν2β), experimentally observed in eleven isotopes with half-lives in the range 1018–1024 years (see reviews [8,9,10] and references therein) and allowed in the Standard Model, the 0ν2β decay has not been detected yet. High-quality radiopure CdWO4 crystal scintillators were developed from deeply-purified cadmium samples enriched in the isotopes 106Cd [29] and 116Cd [30] with the help of the low-thermal-gradient Czochralski crystal-growth technique [31].

Results

Conclusion