High-resolution alpha-particle spectrometry of ²⁴³Am

Alpha particles emitted by a thin ²⁴³Am source were detected with an energy resolution of 9-10 keV in a planar ion-implanted silicon semiconductor detector. A magnet system was installed above the source to deflect conversion electrons emitted quasi-coincidentally with the alpha particles, thus strongly reducing sum peaks from simultaneous detections that would distort the energy spectrum. In addition, measurements were performed at different distances between the source and detector surfaces, to verify whether the energy spectra were insensitive to variations in geometrical efficiency. Peak shapes were fitted to the energy spectrum, the alpha-particle emission probabilities determined, the uncertainty budget calculated, and the results compared with literature values.