Decay Properties of 74-SecondAg111m

Silver activities were separated by a rapid elution with concentrated HCl from an anion-exchange column containing 22.5-min ${\mathrm{Pd}}^{111}$ as Pd${\mathrm{Cl}}_6^{=}$ from deuteron-bombarded ${\mathrm{Pd}}^{110}$. The decay of ${\mathrm{Ag}}^{111m}$ was observed with a half-life of 74±3 sec, and its radiations were compared by aluminum absorption with those of 40-sec ${\mathrm{Ag}}^{109m}$. Conversion electrons and x-rays are seen, with less than 0.1% $\beta$ decay to ${\mathrm{Cd}}^{111}$. Search for 49-min ${\mathrm{Cd}}^{111m}$ showed less than 0.01% $\beta$ decay to this species. Essentially all of the decay of ${\mathrm{Pd}}^{111}$ goes to ${\mathrm{Ag}}^{111m}$.