Investigation of the 2νEC/EC Decay of 106Cd

Abstract

Search for the β+β+, β+EC, and EC/EC modes of the 106Cd decay was carried out with the TGV-2 (Telescope Germanium Vertical) low-background multidetector spectrometer installed at the Modane underground laboratory (4800 m w.e.). The measured foil samples ∼50 μm thick and 52 mm in diameter were placed between the entrance windows of the neighboring detectors inside the cryostat. The total measurement time for 10 g of 106Cd enriched to 75% was 8687 h. New limits (at the 90% confidence level, CL) were obtained for the 106Cd half-lives against various branches of the decay to the ground state 0+ and excited states 2+ of the 106Pd daughter nucleus. They are T1/2(2νβ+β+) ≥ 6.0 × 1019 y, and T1/2(2νβ+EC) ≥ 5.9 × 1019 y, and T1/2(2νEC/EC) ≥ 3.0 × 1020 y for the transitions to the 0+ ground state of 106Pd; T1/2(2νβ+β+) ≥ 5.7 × 1019 y, T1/2(2νβ+EC) ≥ 5.9 × 1019 y, and T1/2(2νEC/EC) ≥ 4.2 × 1019 y for the transitions to the 2+, 512-keV excited state of 106Pd; and T1/2(2νEC/EC) ≥ 3.1 × 1019 y for the transition to the 01+, 1334-keV excited state of 106Pd.