Parity method for activity measurements
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The present state of the development of a new method for activity measurements is reported applicable to nuclides decaying in two steps, with emissions that can be measured separately. Such radioactive sources are now usually measured by the coincidence method. The new approach, since no coincidences are performed, should also be applicable to isomeric transitions with short half-lives. The method is based on a simple observation. Whenever both emissions of a given two-step decay are detected, they obviously contribute two units to the total number of observed pulses (normally betas and gammas), whereas events without a partner in the opposite channel add only one. In the registration of the sum by modulo 2 counting, the paired events have no effect on the output, which is either 0 for even or 1 for odd numbers. By repeated measurements, always within a small counting time, the probability for parity 1, for example, can be determined. This parameter is characteristic to the process and, together with the mean value, allows us to determine the number of paired events, which essentially correspond to the true coincidences. The basic principles, the experimental realization and the encountered problems will be discussed. It can be anticipated that some further improvements in the analysis will soon transform this approach into a useful measuring method.
KeywordsBasic Principle Measuring Method Present State Activity Measurement Experimental Realization
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