Double beta decay of 150Nd to the first 0+ excited level of 150Sm

An experiment to measure the 2beta– decay of 150Nd to excited levels of 150Sm using a highly purified 2.381 kg of Nd_2O_3 sample is in progress in the low-background set-up with 4 HPGe detectors (~ 225 cm^3 volume each). The detector is located deep underground (3600 m w.e.) at the STELLA facility of the Gran Sasso National Laboratory (LNGS) of the INFN (Italy). Two gamma quanta with energies 334.0 keV and 406.5 keV emitted after deexcitation of the 0_1^+ excited level of 150Sm have been observed in the experimental data accumulated over 39898 h. The preliminary half-life value for 2beta– decay of 150Nd to the first 0^+ excited level in 150Sm over 39898 h was estimated as T_1/2=[9.7^(+2.9)_(-1.9)(stat)+/-1.5 (syst)]x10^19 yr. The experiment is under data taking with the aim to improve the statistical uncertainties.