Nuclear orientation and angular correlation studies of gamma transitions in151Sm from the decay of151Pm

Abstract

The levels and gamma ray transitions in 151Sm have been investigated using the two complementary techniques of directional correlation, and the directional distribution of radiation emitted by an oriented source. The orientation was produced using the hyperfine field in ferromagnetic gadolinium to polarize an ensemble of 151Pm nuclei at a temperature of 11 mK. The resultant directional distribution of the gamma rays was measured using high resolution Ge detectors. The correlation measurements used an intrinsic Ge detector in combination with a Ge(Li) detector. These two types of result enabled multipole mixing ratios to be determined for 34 gamma transitions in the decay, and unambiguous spin assignments to be made for the levels connected by these transitions. This latter information in particular should make it easier to decide whether this nucleus can be described in terms of Nilsson single particle states.