Search for double beta decay of 106Cd in the TGV-2 experiment

An investigation of double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (at a water equivalent depth of 4800 m) using a TGV-2 spectrometer with 32 detectors. Evaluation of the experimental data accumulated over 12 400 h of measuring ∼13.6 g of 106Cd with an enrichment of 75% was performed. New limits (at a confidence level of 90%) on the half-lives of the 0νEC/EC resonant decay of 106Cd to the 2741 keV excited state of 106Pd − T1/2 ≥ 1.5 × 1020 y and on 2νEC/EC decay to the ground state of 106Pd (0+ → 0+, g.s.) − T1/2 ≥ 3.9 × 1020 y were obtained. The limits of the 2νEC/EC decay of 106Cd to the 2+, 512 keV and 01+, 1334 keV excited states of 106Pd and 2νβ+β+- and the 2νβ+EC decays of 106Cd to the ground and excited states of 106Pd were improved.