Energy resolution improvement in simplified alpha spectroscopy for radionuclidic purity tests on 225Ac production floors

This study investigated the feasibility of a simplified method of alpha spectroscopy for radionuclidic purity tests at 225Ac production sites that eliminates the need for a vacuum chamber. The impact of enhancing the energy resolution using a collimator was evaluated through radiation transport simulations. The results showed that a full width at tenth maximum (FWTM) of <300 keV was achieved for alpha particles from 241Am, for which the main energy peak was 5.5 MeV. Experimental validation using an electrodeposition source containing 237Np, 241Am, and 244Cm confirmed an FWTM of 272 keV for both 241Am and 244Cm. These two peaks, with a difference of ~300 keV, were effectively separated. In response to the growing demand for targeted radioisotope therapy, this simplified alpha spectroscopy method offers the potential to detect 226Ra mixed with 225Ac generated by accelerators, given the alpha energy difference of ~700 keV.