Decay ofNd149toPm149

Abstract

The radiations from the decay of the 1.8-h ${\mathrm{Nd}}^{149}$ have been investigated using an intermediate-image betaray spectrometer and scintillation coincidence spectrometers in conjunction with a 512-channel analyzer. Various gamma-gamma and beta-gamma coincidence measurements, not reported earlier, have been made in order to establish the decay scheme with improved techniques. The beta spectrum showed four major components with end-point energies 1555 keV (6%), 1425 keV (38%), 1130 keV (26%), and 1025 keV (30%). The singles gamma-ray spectrum showed the following gamma rays: 62, 80, 114, 158, 190, 210, 240, 272, 330, 375, 425, 540, and 650 keV. 62, 80, 158, 272, and 330 keV gamma rays were not reported earlier. To explain the various gamma-gamma and beta-gamma coincidences a new decay scheme with levels in ${\mathrm{Pm}}^{149}$ at 114, 210, 272, 352, 510, 538, 650, and 750 keV is proposed. The $K$-conversion coefficient of the 114-keV transition, which is not determined earlier, has been measured and is found to be 0.83±0.1.