Method and equipment for estimation activity nuclides in samples of finite dimensions

This study presents a method of measuring the activity of a specific radionuclide ^234mPa in samples placed in bulk transport containers under changing background conditions. The method makes it possible to measure specific activity of ^{234 m}Pa in objects without the need for sampling. The change in the effective sample volume limited by the surfaces of the containers is considered depending on the density of the measured material and the energy of gamma radiation of the radionuclide. The high sensitivity of scintillation detector, supplemented by adequate Monte Carlo simulation, allows spectrum measurements to be taken in a short time (less than an hour) with subsequent determination of specific activity. A comparison of measurement results and calculation of ^234mPa activity in samples with different densities and compositions using the proposed algorithm, and those obtained by an HPGe spectrometer, demonstrated the high efficiency of the proposed solution.