The Induced Radioactivity of Krypton and Xenon

Irradiation of krypton with deuterons of 11 Mev produces krypton activities with half-lives of 102 minutes, 4.0 hours, and about 35 hours. When selenium is bombarded with 22-Mev alpha-particles, there appear krypton activities of 114 minutes and about 33 hours. The 114-minute period coincides with that reported by other investigators as due to a krypton isotope growing out of ${\mathrm{Br}}^{83}$, and hence is assigned to ${\mathrm{Kr}}^{83*}$. The 102-minute period observed in deuteron irradiation is considered to be the same activity. ${\mathrm{Kr}}^{87}$, an isotope which cannot be formed from alpha-particle reactions with selenium, is probably the source of the 4.0-hour activity. The weak 33-35 hour activity is due to ${\mathrm{Kr}}^{79}$ or ${\mathrm{Kr}}^{81}$. ${\mathrm{Kr}}^{85}$ is presumed to have an activity long or fairly short. Irradiation of xenon with deuterons produces xenon activities of 68 minutes, 9.6 hours, and 5.4 days. Of these, the last also appears in the irradiation of tellurium with alpha-particles, and is due to ${\mathrm{Xe}}^{133}$. The 9.6-hour activity is assigned to ${\mathrm{Xe}}^{135}$. ${\mathrm{Xe}}^{137}$ is the most probable source of the 68-minute activity.