Radioactive isotopes of barium of half-lives 40.0 hours and 340 hours are made by bombarding cesium with deuterons of 9.5 Mev energy. The former is shown by absorption measurements and by the magnetic beta-spectrometer to consist of a partially converted gamma-ray of energy 276.4 kev. The latter activity is associated with $K$-electron capture in ${\mathrm{Ba}}^{133}$ and consists solely of a 17-kev gamma-ray and the $K$ x-radiation of cesium of energy about 30 kev. The 40.0-hour activity is probably due also to a highly excited state of ${\mathrm{Ba}}^{133}$, although the existence of an excited state of the stable ${\mathrm{Ba}}^{134}$ would equally well satisfy the data. The probability of total conversion for the 40.0-hour gamma-ray is about 71 percent, and the ratio of the $K$ and $L$ components is found to be 3.18. From the calculations of Hebb and nelson this indicates a change in angular momentum of four units.

• Received 11 August 1941

DOI:https://doi.org/10.1103/PhysRev.60.480