The radiations of ${\mathrm{Os}}^{185}$ have been examined in a thin magnetic lens beta-ray spectrometer and in coincident scintillation spectrometers. By these means, gamma rays of energies 75, 122, 158, 233, 593, 643, 718, 750, 870, and 878 kev have been observed, revealing excited energy levels of the residual nucleus, ${\mathrm{Re}}^{185}$, at 122, 643, 718, 870, and 878 kev. Internal conversion coefficient measurement showed the 643-kev gamma ray to be predominately $E2\mathrm{}$. A search for positrons was made by observing gamma-gamma coincidences with the counters placed at 180° and 90°. An upper limit of (4±3)×${10}^{-6\mathrm{}}$ positron per disintegration could be set.

• Received 31 March 1958

DOI:https://doi.org/10.1103/PhysRev.111.1291