Background Reduction For Germanium Double Beta Decay Experiments

The new generation experiments to search for the neutrinoless double beta decay of 76Ge (Qββ=2039keV) using enriched germanium detectors, need to reach a background level of ∼10-3 c keV-1 kg-1 y-1 in the Region of Interest (RoI: 2-2.1 MeV) that would have, for 70 kg of germanium enriched to 86% in 76Ge, 3 keV of FWHM and 5 years of measuring time, a sensitivity on the effective neutrino mass of ≤ 40 meV. To reduce the background level close to the value needed, we have to combine several techniques. Three of the most important points to study are: segmentation and granularity of the crystal and spatial resolution of the detector directly correlated with an offline Pulse Shape Analysis (PSA). Preliminary studies about these strategies for background reduction were developed during last months, obtaining some promising results