A Study of the Decay Scheme of Eu146

Abstract

The level scheme of Sm 146 fed from (4.59±0.03)-days Eu 146 has been investigated with scintillation spectrometers, beta-ray spectrometers, gamma-gamma and Ke - -gamma coincidences, and directional correlation techniques. From the measurements of internal conversion electrons, several new transitions were found in addition to those reported by the previous workers. Levels in Sm 146 were established at the following energies: 750 (2 + ), 1387, 2056, 2287, 2448 and 2686 keV, and also 1654 and 1820 keV. Besides these, about 10 levels were postulated on the basis of energy, intensity and coincidence considerations. From analysis of the positrons and from the fact of absence of crossover transition to the ground state, the spin-parity of the second-excited level at 1387 keV was expected to be 4 + . This assignment, however, was not consistent with the results of the directional correlation measurement for the de-excitation gamma-ray cascade and the K -conversion coefficient for the transition proceeding from t...