COBRA - Double beta decay searches using CdTe detectors

A new approach (called COBRA) for investigating double beta decay using CdTe (CdZnTe) semiconductor detectors is proposed. It follows the idea that source and detector are identical. This will allow simultaneous measurements of 5 $\beta^-\beta^-$ - and 4 $\beta^+\beta^+$ - emitters at once. Half-life limits for neutrinoless double beta decay of Cd-116 and Te-130 can be improved by more than one order of magnitude with respect to current limits and sensitivities on the effective Majorana neutrino mass of less than 1 eV can be obtained. Furthermore, for the first time a realistic chance of observing double electron capture processes exists. Additional searches for rare processes like the 4-fold forbidden Cd-113 $\beta$-decay, the electron capture of Te-123 and dark matter detection can be performed. The achievable limits are evaluated for 10 kg of such detectors and can be scaled accordingly towards higher detector masses because of the modular design of the proposed experiment.