Radiations from Four Radioactive Isotopes of Platinum

The gamma radiations of the 18-hr ${\mathrm{Pt}}^{197}$ have been examined with scintillation counting methods and have been found to consist of 77- and 191-kev quanta in coincidence and a 279-kev gamma ray which is noncoincident with other gamma rays. Beta-gamma coincidence studies have been performed and values of $log\mathrm{ft}$ have been obtained for the three beta-ray spectra of ${\mathrm{Pt}}^{197}$. The radiations of ${\mathrm{Pt}}^{195m}$ include gamma rays of energies 31, 99, and 130 kev. The latter gamma ray is not to be confused with the highly converted one emitted in the 3.8-day isomeric transition and is the cross over of the 31-kev-99-kev cascade. ${\mathrm{Pt}}^{193m}$ emits a gamma ray of energy 130 kev. No quantum radiations of higher energies were detectable. Some coincidence measurements have been performed on the complex gamma-ray spectrum of ${\mathrm{Pt}}^{191}$.