Decay of¹⁴⁸Pr Isomers to Levels of¹⁴⁸Nd

Abstract

The decay of 148 Pr to levels on 148 Nd has been investigated with Ge(Li) and plastic detectors in singles and coincidence modes. Sources were prepared by a chemical separation from the fission products of 235 U. Forty γ-rays associated with 148 Pr decay have been observed and thirty four of them are incorporated into a level scheme including six new levels at 723.7, 1275.0, 1512.4, 1687.5, 2543.0 and 3129.6 keV. In comparison with the decay study of 148 Pr produced by the 148 Nd(n, p) reaction, this work, for the first time, could make clear the existence of 148 Pr isomers by γ-ray intensity ratios and their half-lives which are 2.27 ±0.04 and 2.0 ±0.1 min. A low lying level at 723.7 keV is assigned as a 0 + state from the γ- γ anisotropy measurements and low lying levels in the transitional nuclide 148 Nd are discussed in terms of the quasi band description.