Performances of a large mass ZnSe bolometer to search for rare events
Résumé
Scintillating bolometers of ZnSe are the baseline choice of the LUCIFER experiment, whose aim is to observethe neutrinoless double beta decay of 82Se.The independent read-out of the heat and scintillation signalsallows to identify and reject α particle interactions, the dominant background source for bolometric detectors.In this paper we report the performances of a ZnSe crystal operated within the LUCIFER R&D.We measured the scintillation yield, the energy resolution and the background in the energy region where the signal from 0νDBD decay of 82Se is expectedwith an exposure of 9.4 kg*days.With a newly developed analysis algorithm we improved the rejection of α events,and we estimated the increase in energy resolution obtained by the combination of the heat and light signals.For the first time we measured the light emitted by nuclear recoils, and found it to be compatible with zero.We conclude that the discrimination of nuclear recoils from β/γ interactions in the WIMPs energy regionis possible, but low-noise light detectors are needed.