Search for double beta decay of 106 Cd

A search for the β + β + , β + /EC, and EC/EC decays of 106 Cd was performed at the Modane Underground Laboratory (France) located at a depth of 4800 m w.e. using a TGV-2 multidetector germanium spectrometer. A preliminary evaluation is performed of the experimental data accumulated during the measurements (12 900 h) of ∼13.6 g of 106 Cd (with an enrichment of 75%) and the spectrometer background without samples and with samples of natural Cd. New limits (at a 90% confidence level) of half-lives are obtained: T 1/2 ⩾ 1.7 × 10 20 yr and T 1/2 ⩾ 1.6 × 10 20 yr for the 0νEC/EC resonant decay of 106 Cd to the 2741 keV and 2718 keV excited states of the daughter nucleus 106 Pd and T 1/2 ⩾ 4.2 × 10 20 yr for the 2νEC/EC decay to the ground state of 106 Pd (0 + → 0 + , g.s. ). The limits for other branches of the double beta decay of 106 Cd with transitions to the ground and excited states of 106 Pd are improved.