Direct determination of 90Sr and 147Pm by absolute β counting in aerosol samples collected after the Chernobyl accident

Defined solid angle absolute β counting with the aid of absorption measurements can be applied in certain cases to determine the activity of a β emitter in a thick sample which contains a few known radionuclides. Although the application of this method is limited to special cases and high precision cannot be reached, the method may be useful in certain low-level radioanalytical studies. The absolute activity of 90Sr and 147Pm has been determined by this method without any chemical treatment in airfilter samples containing radioactivity of Chernobyl origin a few years after the accident. 90Sr/137Cs and 147Pm/137Cs activity ratios have also been evaluated. (orig.)