Pulse shape analysis with scintillating bolometers

Rare event searches impose strict requirements to the detectors such as an excellent energy resolution, a high detection efficiency and a very low background level. The bolometric technique has already proven to be very promising in this field. Among the features on which it is possible to further act to improve the detection sensitivity, the radioactive background reduction covers a primary role. This request can be satisfied through the possibility to identify the nature of the interacting particle. However, up to now, this opportunity can be fulfilled only with a double readout (e.g. heat and scintillation light). This double readout could greatly complicate the assembly of a huge, multi-detector array. The possibility to recognize the interacting particle through the shape of the thermal pulse is therefore a very interesting opportunity. Detailed analysis of the signal time development in macro-bolometers composed by scintillating crystals showed that it is possible to distinguish between β/γ and α particle interaction (i.e. the main source of background for 0νDBD experiments based on the bolometric technique). Results of pulse shape analysis of signals from several bolometers with absorbers of different compositions (CaMoO4, ZnMoO4, ZnSe) are presented and the pulse shape discrimination capability of such detectors is discussed. An explanation of this behavior, based on the energy partition in the heat and scintillation channels, is also presented