The Nuclear Excitation ofAg107andAg109by X-Rays

X-rays, produced by monoergic electrons, were used to excite the separated isotopes of silver to their metastable states. The half-life of ${\mathrm{Ag}}^{107*}$ was found to be 44.0±1.0 seconds. The half-life of ${\mathrm{Ag}}^{109*}$ was found to be 40.0±1.0 seconds. These measurements are in agreement with those of Bradt, et al, and the isotopic assignment of Helmholz. The electron energy was varied between 0.8 Mev and 2.3 Mev in order to obtain the excitation curves. The thresholds for x-ray excitation of both ${\mathrm{Ag}}^{107}$ and ${\mathrm{Ag}}^{109}$ were found to be below 0.8 Mev. An activation level in ${\mathrm{Ag}}^{107}$ was found at 1.285±0.018 Mev. An activation level in ${\mathrm{Ag}}^{109}$ was found at 1.210±0.018 Mev. The over-all cross section (i.e., per incident electron on thick gold target) is of the order of ${10}^{-34\mathrm{}}$ ${\mathrm{cm}}^2$ for both isotopes at 1.4 Mev.