Towards a background-free double-beta decay experiment using the EDELWEISS cryogenic Ge detectors

The present generation of double-beta experiments is limited by two main backgrounds: surface alpha interactions and Compton interactions from high-energy gamma-ray lines. Using the detector developments realized for the EDELWEISS Dark Matter experiment, we propose a strategy to eliminate completely the alpha radioactivity background and to reduce by nearly two orders of magnitude the Compton background. This would lead to a nearly background-free experiment, and an effective neutrino mass sensitivity of 15 meV achieved in 5 years with a one-ton array of ionisation-heat 76Ge detectors.