Nuclear Spectroscopy ofBa131andCs131

Abstract

The spectra of ${\mathrm{Ba}}^{131}$ and ${\mathrm{Cs}}^{131}$ have been investigated in a magnetic lens spectrograph. The 12-day ${\mathrm{Ba}}^{131}$ decays by orbital electron capture. Gamma-rays at 0.497, 0.371, 0.241, 0.213, 0.196, and 0.122 Mev have been observed. ${\mathrm{Cs}}^{131}$ (10-day) decays entirely by orbital electron capture. No gamma-rays are associated with this transition. In the particle spectrum only Auger electrons are found. There are no internal conversion lines which could arise from the 0.080- and 0.163-Mev states of ${\mathrm{Xe}}^{131}$. It is concluded that ${\mathrm{Cs}}^{131}$ decays to the ground state of ${\mathrm{Xe}}^{131}$.