Gamma-Ray Intensities for the Radioactive Decay of Barium-140 and Lanthanum-140

Gamma-ray spectra from the radioactive decay of ¹⁴⁰Ba and ¹⁴⁰La were observed by Ge(Li) spectroscopy. Gamma-ray energies were found to be consistent with literature values, but several of the observed gamma rays were found to have intensities differing significantly from those previously reported. Absolute intensities of prominent gamma rays emitted in the radioactive decay of ¹⁴⁰Ba and ¹⁴⁰La have been measured. The 12.8-day ¹⁴⁰Ba activity was produced by 14.8-MeV neutron fission of ²³⁸U followed by radiochemical separation and purification.