Electron Spectrum of theU230Decay Series

Abstract

The energies of the first excited states of ${\mathrm{Th}}^{226}$, ${\mathrm{Ra}}^{222}$, and ${\mathrm{Em}}^{218}$ have been measured as 72.13±0.06, 111.1±0.3, and 324.6 kev with photographic-recording beta-ray spectrographs. The energy of the second excited state in ${\mathrm{Th}}^{226}$ has been measured as 226.4 kev, and a comparison is made with predictions of the Bohr-Mottelson nuclear model.