Gamma-Ray Spectrum ofAc228

The gamma radiation from a radioactively pure source of ${\mathrm{Ac}}^{228}$ has been studied using a NaI scintillation spectrometer. Gamma rays of 0.098, 0.127, 0.336, 0.410, 0.458, 0.907, 0.965, 1.587, 0.155, 0.220, 0.278, and 0.790 Mev are indicated, of which the last four are previously unreported. A double scintillation spectrometer is described which was used to investigate gamma-gamma coincidences. A decay scheme for ${\mathrm{Ac}}^{228}$ is suggested.