Development of an ultrahigh resolution real time alpha particle imaging system for observing the trajectories of alpha particles in a scintillator

Abstract

High-resolution imaging of alpha particles is required in the detection of alpha radionuclides in cells or small organs for the development of radio-compounds for targeted alpha-particle therapy or other purposes. We developed an ultrahigh resolution, real time alpha-particle imaging system for observing the trajectories of alpha particles in a scintillator. The developed system is based on a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera, combined with a 100-µm-thick Ce-doped Gd3Al2Ga3O12 (GAGG) scintillator plate. Alpha particles from an Am-241 source were irradiated to the GAGG scintillator and imaged with the system. Using our system, we measured the trajectories of the alpha particles having different shapes in real time. In some of these measured trajectories, the line shapes of the alpha particles that flew in the GAGG scintillator were clearly observed. The lateral profiles of the alpha-particle trajectories were imaged with widths of ~ 2 µm. We conclude that the developed imaging system is promising for research on targeted alpha-particle therapy or other alpha particle detections that require high spatial resolution.

Range and light output measurements of trajectory images in a GAGG plate with different alpha particle energies

“…The field of view (FOV) for the EM-CCD camera was 200 μm × 200 μm, with a pixel size of 0.4 μm × 0.4 μm. The spatial resolution, determined from the widths of the alpha particle trajectories, was 1.2 μm, slightly surpassing the performance of the initial system used for trajectory imaging [12]. This enhancement in spatial resolution can be attributed to the use of the finely polished GAGG plate, which features a smoother surface, conducive to high-quality and high resolution imaging.…”

“…Figure 1(a) shows a schematic diagram illustrating the trajectory measurements for alpha particles of varying energies. The imaging system employed in these measurements closely resembles the previously developed trajectory imaging system, characterized by its reliance on a magnifying unit, an EM-CCD camera, and the incorporation of a thin GAGG scintillator plate [12]. Notably, for these experiments, Mylar films were introduced between the alpha source and the GAGG plate.…”

“…Recently, a high-resolution alpha-particle imaging system was developed, employing a scintillator plate combined with a magnifying unit and a cooled electron multiplying CCD (EM-CCD) camera, which achieved approximately 2 μm spatial resolution [12]. With this imaging system, the trajectories of alpha particles became distinctly observable in real-time [12].…”

Ultrahigh resolution real-time trajectory imaging of neutron induced particles in a scintillator from lithium-6 plate

“…The pixel size of our imaging system was 1 μm, with a 20× objective lens used for imaging. We previously used a 40× lens for alpha particle imaging with a GAGG plate and achieved ∼ 2 μm spatial resolution [21]. Therefore, higher spatial resolution would be possible using an objective lens with higher magnification as well as reduced field-of-view.…”

“…We previously combined a fiber-structured scintillator plate and a high-sensitivity CCD camera to observe the trajectories of alpha particles [16,17]. We also achieved high-resolution, real-time imaging of X-rays and alpha particles by combining scintillators with a high-sensitivity CCD camera and a magnifying unit [19][20][21]. Moreover we imaged neutron induced particle's spots in Li-ZnS(Ag) film with the system [22] but clear trajectories were not images because Li-ZnS(Ag) was opaque.…”