Trial of three-dimensional image estimation from two-dimensional projected trajectory images of alpha particles in GAGG scintillator

Abstract High-resolution trajectory images of alpha particles emitted by Ac-225 and its daughter radionuclides were obtained using a Gd 3 Al 2 Ga 3 O 12 (GAGG) scintillator combined with a magnifying unit and a high-sensitivity CCD camera. However, these images were limited to two-dimensional (2D) projections. To achieve more precise estimations of alpha particle trajectories, three-dimensional (3D) images were desired. For this purpose we tried to estimate 3D images by analyzing the intensities and projected ranges of 2D trajectory images of 8.4 MeV alpha particles emitted by an Ac-225 daughter radionuclide, Po-213. First, 8.4 MeV alpha particles were identified based on the total intensity of their trajectories. Then, their incident angles were estimated using the intensity in shallow regions and projected ranges of the trajectories. These estimated angles were used to reconstruct trajectory images along the direction perpendicular to the GAGG scintillator plate. Using this method, we successfully estimated 3D alpha particle trajectories from their 2D projection images.