Radioactive Isotopes of Ga and Ge

Abstract

The radioactive germanium isotope of 1.65-day half-life has been produced by $\mathrm{Zn}(\ensuremath{\alpha},n)$, $\mathrm{Ga}(d,2n)$, and $\mathrm{Ge}(n,2n)$ reactions, but not by deuteron bombardment of germanium. This isotope is reassigned and placed at ${\mathrm{Ge}}^{69}$. It decays with emission of positrons, x-rays, and gamma-rays. No evidence for the existence of the 195-day period has been found at ${\mathrm{Ge}}^{69}$ by deuteron bombardment of gallium. The characteristic x-ray lines of gallium from decay activity of the 11.4-day ${\mathrm{Ge}}^{71}$ have been photographed by a curved crystal camera. Deuteron bombardment of ${\mathrm{Ge}}^{76}$, enriched electromagnetically to 70 percent, has given no evidence of a 9-day period at ${\mathrm{Ga}}^{74}$. The half-life of ${\mathrm{Ge}}^{75}$, produced by fast neutron bombardment of arsenic, is 1.37\ifmmode\pm\else\textpm\fi{}0.02 hours. The half-life of ${\mathrm{Ga}}^{67}$, produced by alpha-particle bombardment of zinc, is 3.26\ifmmode\pm\else\textpm\fi{}0.02 days.