Double Beta Decay Of Nd-150 To The First 0(+) Excited Level Of Sm-150

An experiment to measure the 2 beta(-) decay of Nd-150 to excited levels of Sm-150 using a highly purified 2.381 kg sample of Nd2O3 is in progress in the low-background set-up with 4 HPGe detectors (similar to 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. quanta with energies 334.0 keV and 406.5 keV emitted after deexcitation of the 0(1)(+) excited level of Sm-150 have been observed in the experimental data accumulated over 39898 h. The preliminary half-life value for 2 beta(-) decay of Nd-150 to the first 0(+) excited level in Sm-150(after the exposure of 10.8 kg x yr) was estimated as T-1/2 = [9.7(-1.9)(+2.9) (stat.) +/- 1.5(syst.) x 10(19) yr. The experiment is under data taking with the aim to improve the statistical uncertainties.