Australian Nuclear Science and Technology Organisation
Abstract
The activity of molybdenum 99 freshly separated from technetium is absolutely measured to ± 1.8 per cent, by 4πв-γ coincidence counting. Internal conversion effects are allowed for and the completeness of the separation is checked from the growth rate of technetium 99m activity as measured in a 4П gamma ionisation chamber. The chamber has been calibrated for molybdenum 99 with ingrown technetium 99m and for pure technetium 99m and serves for routine activity measurements of solutions of these nuclides to an accuracy of ± 3 per cent