Decay of Neodymium-147

Abstract

The decay of ${\mathrm{Nd}}^{147}$ has been investigated using scintillation spectroscopy and coincidence technique. The following sequences of gamma emission have been uniquely established: 91-kev gamma ray is in coincidence with 120, 199, 277, 322, 400, 442, and 599-kev gamma rays; 120-kev gamma ray with 322- and 413-kev gamma rays; 199-kev gamma ray with 400- and 491-kev gamma rays; 277-kev gamma ray with 322- and 413-kev gamma rays; and 310-kev gamma ray with 322- and 413-kev gamma rays. On the basis of these gamma-gamma sequences, the levels of ${\mathrm{Pm}}^{147}$ at 91, 413, 491, 533, 690, and 723 kev above the ground state are unambiguously established. A critical analysis of the observed coincidence spectra shows that the levels at 182 and 230 kev, suggested by other workers, either do not exist or, if they exist, are not populated by any beta transition of intensity more than a percent or by any gamma transition from other higher energy levels, of intensity more than 0.1%.