Half-Lives of $^{101}$Rh and $^{108m}$Ag

Half-lives of short-lived nuclei can easily be measured by direct counting techniques, whereas those of long-lived naturally-occurring nuclei are usually determined by specific activity measurements. However, half-lives in the range of 1 -- 1,000,000 years are notoriously difficult to determine. For example, published values for the half-life of $^{101}$Rh range from 3.0 $\pm$ 0.4 years to 10 $\pm$ 1 years, and for $^{108m}$Ag published values range from 127 $\pm$ 21 years to 438 $\pm$ 9 years. In order to resolve the issues of what the half-lives of these isotopes actually are, we set up two separate long-term gamma-ray counting experiments. Gamma-ray data were collected in time bins using high-purity Ge detectors and ORTEC PC-based data acquisition systems. We counted in this manner for a period of approximately 5 years for $^{101}$Rh and 3 years for $^{\mathrm{108m}}$Ag. In this talk we will describe the details of these experiments and will present the final results for the half-lives of $^{101}$Rh and $^{\mathrm{108m}}$Ag determined from these measurements.