Search

Cadmium-116 is one of the favorable candidates for neutrinoless double-beta decay ( 0 ν β β ) searches from both theoretical and experimental points of view, in particular thanks to the high energy of the decay (2813.49 keV), the possibility of the industrial enrichment in 116 Cd and its use in the well-established production of cadmium tungstate crystal scintillators. In this work, we present low-temperature tests of two 0.6 kg 116 CdWO 4 crystals enriched in 116 Cd to 82 % as scintillating bolometers. These detectors were operated underground, with one at the Laboratoire Souterrain de Modane (LSM) in France and the second at the Laboratorio Subterraneo de Canfranc (LSC) in Spain. The two crystals are coupled to bolometric Ge light detectors in order to register the scintillation light. The double readout of heat and scintillation enables reduction in the background in the region of interest by discriminating between different populations of particles. The main goal of these tests is the study of the crystals' radiopurity and the detectors' performance. The achieved results are extremely promising, in particular, the detectors demonstrate a high energy resolution (11–16 keV FWHM at 2615 keV) and a high-efficiency discrimination of the alpha background ( ∼ 20 σ ). These results, achieved for the first time with large mass enriched 116 CdWO 4 crystals, demonstrate prospects of the bolometric technology for high-sensitivity searches of 116 Cd 0 ν β β decay. [ABSTRACT FROM AUTHOR]

Abstract: A 46g BGO (Bi4Ge3O12) scintillating bolometer has been tested at 20mK as a prototype for dark matter direct detection in the frame of the ROSEBUD (Rare Objects SEarch with Bolometers UndergrounD) collaboration. The bolometer has been operated first in Orsay and then in an ultra-low background environment at the Canfranc Underground Laboratory. We analyze its response both in heat and light, and its particle discrimination capability. Light yield under γ-ray excitation at several energies (from 88.0 to 1633.3keV) and the relative light output for different particles (β/γ, α and neutrons) have been estimated. The analysis focuses on the discrimination of nuclear recoils, like those produced by hypothetical weakly interacting massive particles (WIMPs), against electron recoils, produced by β/γ radioactive background. [Copyright &y& Elsevier]