Radioactive Isotopes of Ru and Tc

A new isotope of Ru and one of Tc were found when Mo was bombarded with alpha-particles. The Ru activity decayed with a half-life of 1.65±0.05 hours. Positrons, x-rays, and gamma-rays were emitted with energies of 1.1 Mev, 0.7A, and 0.95 Mev, respectively. The Ru activity also was produced by fast neutron bombardment of Ru. The Tc activity decayed with a half-life of 20.0±0.5 hours and emitted x-rays of 0.7A and gamma-rays of 0.78 Mev. The Tc activity also was made by proton bombardment of Mo. Electromagnetically separated ${\mathrm{Mo}}^{92}$ of 92 percent abundance was bombarded with alpha-particles producing the 1.65-hour and 20-hour activities. Electromagnetically separated ${\mathrm{Mo}}^{94}$ of 75 percent abundance under alpha-particle bombardment made a 2.8-day activity. Thus the 1.65-hour, 20-hour, and 2.8-day activities can be assigned to ${\mathrm{Ru}}^{95}$, ${\mathrm{Tc}}^{95}$, and ${\mathrm{Ru}}^{97}$, respectively.