Investigation and measurement of factors affecting full width at half maximum (FWHM) in alpha spectrometry

Alpha emitting radionuclides have characteristic and discrete alpha particles from which the type and energy of the alpha emitter can be identified. The unique features of alpha spectrometry compared to other radiometric techniques such as gamma spectrometry are its very low background radiation and the energy independence of the detection efficiency. The aim of this study was to investigate the effect of factors such as alpha particle energy, sample distance to the detector and detector size on the resolution of the alpha spectrometer system. Using an Alphaquattro multi-channel alpha spectrometer manufactured by SILENA, the peak resolution (FWHM) for different energies, different sample-to-detector distances and different detector sizes were investigated. The results of this study showed that the peak resolution improved with increasing sample distance from the detector, but did not change significantly with changing detector size and alpha particle energy. On the other hand, by increasing the distance of the source from the detector, the detection efficiency decreases. For the best performance, the optimal distance should be considered or when the distance is long, the vacuum conditions should be improved and the counting time should be increased.