First test of an enriched 116 CdWO 4 scintillating bolometer for neutrinoless double-beta-decay searches

Abstract

For the first time, a cadmium tungstate crystal scintillator enriched in 116Cd 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 high energy resolution (2–7 keV FWHM in 0.2–2.6 MeV γ energy range and 7.5 keV FWHM at the 116Cd double-beta decay transition energy of 2813 keV), a powerful particle identification capability and a high level of internal radio-purity. These results prove that cadmium tungstate is a 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).