Characterization of Broad Energy GermaniumDetector (BEGe) as a candidate for the GERDA Experiment

Broad Energy Germanium detectors (BEGe) offer an excellent discrimination power for pulse shape analysis of signals induced by interactions in the active volume of the detector. Such a feature makes them potential candidates for double beta decay experiments. In fact, analysis of time development of pulses allows to reject multi sites events (MSE) for which ionization takes place in more than one position, from single-site events (SSE) that release all the energy within a small volume. Double beta decay events, characterized by the interactions of the two electrons emitted, belong to the latter category of events, while MSE, mainly γ-rays interactions, constitute the background that has to be rejected. BEGe are currently considered as potential candidates the Phase II of GERDA experiment, looking for 76Ge double beta decay at the INFN Underground Gran Sasso National Laboratory (LNGS). Characterization of a commercial BEGe from Canberra is presented together with the results of the pulse shape analysis. Moreover, a full detector model (electric field and pulse generation), developed to understand the pulse shape discrimination power of the detector and validated with dedicated measurements, is presented and discussed.