Further Investigation of the Radioactivity ofSb124

The shape of the highest energy beta-ray group in ${\mathrm{Sb}}^{124}$ is found to have a forbidden shape that is characteristic of a once-forbidden transition involving a change of two units of angular momentum and a change of parity. As a consequence, the end points of the three highest energy groups are changed somewhat to 2.291±0.005, 1.69±0.01, and 0.95±0.03 Mev. A high resolution measurement of photo-electrons confirms the existence of the 0.607-, 0.653-, and 0.730-Mev gamma-rays. The internal conversion of the 0.607-Mev gamma-ray was studied. The character of the radiation and relation of the parity assignments to possible predictions of the nuclear shell model are discussed. A search for possible positron or $K$-capture transitions to ${\mathrm{Sn}}^{124}$ gave no indication of the existence of such radiation.