Speaker
Description
The $^{150}$Nd nuclide is one of the most promising ones to search for double beta decay among the 35 naturally occurring double beta isotopes because of the high energy release: 3371.38(20) keV, and of the comparatively high isotopic abundance: 5.638(28)%. The 2$\beta$ transition to the 740.5 keV $0_1^+$ excited level of $^{150}$Sm was observed in few experiments with half-lives in a wide range $(7 – 14)\times10^{19}$ y. The investigation of this decay is performed at the Gran Sasso underground laboratory (Italy) with a highly purified 2.381-kg Nd$_2$O$_3$ sample in the low-background setup with 4 HP Ge detectors ($\approx$225 cm$^3$ each), mounted in one cryostat. Two gamma-quanta with energies 334.0 keV and 406.5 keV emitted after the deexcitation of the $0_1^+$ excited level of $^{150}$Sm have been observed in the coincidence spectra accumulated over 25947 h giving the preliminary half-life value of the $^{150}$Nd relatively to the decay searched for: $T1/2=[6.9_{-1.9}^{+4.0}$(stat)$\pm1.1$(syst)$]\times10^{19}$ y. The experiment is in progress in order to improve the half-life value accuracy.
