We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Characterization of GaN:Si and ZnO:Ga for position-resolved fast timing applications
Summary
Scientists tested two new light-detecting crystal materials (GaN:Si and ZnO:Ga) that could improve imaging technologies used in medical scanning and security screening, finding they respond over 3 times faster than the current standard material. This matters because faster, more precise detectors could lead to better medical imaging tools—like those used to spot tumors or guide treatments—with sharper detail and potentially lower radiation doses for patients.
We present the characterization of two fast, crystalline inorganic scintillators, silicon-doped gallium nitride (GaN:Si) and gallium-doped zinc oxide (ZnO:Ga), and compare their performance with cerium-doped yttrium aluminium perovskite (YAP:Ce) for in-vacuum alpha-detection applications that require high-performance timing, position, and energy resolution, such as 3D elemental mapping, medical imaging, and homeland security applications. In this paper, we propose ZnO:Ga and GaN:Si as high-performance drop-in replacements for the alpha detector in Associated Particle Imaging (API) systems. However, the results reported here also have wide applicability. Prior work has reported on polycrystalline forms of ZnO:Ga, which suffer from self-absorption. To our knowledge, GaN:Si has not been proposed to be used in API systems. We present room-temperature scintillation time constants obtained via X-ray-induced time-correlated single-photon counting for both proposed materials. They both exhibit exceedingly fast rise times of <15ps, and high brightness >1000ph/MeV with resolved alpha-peaks. Single-crystal ZnO:Ga and single-crystal GaN:Si yield single-component decays of 805ps and 32ps, respectively. Using a plastic scintillator reference setup, coincidence timing resolution (CTR) and detector timing resolution (DTR) measurements demonstrate a >3x improvement in timing resolution compared to traditional YAP:Ce. GaN:Si and ZnO:Ga exhibit (35(9))ps and (49(5))ps DTR, respectively, compared to(144(2))ps for conventional, single-crystal YAP:Ce. Finally, we evaluate their position resolution in an experimental setup designed for API and measure better than 0.2mm for YAP:Ce and approximately 1mm for GaN:Si. We obtain a position resolution of 0.3mm for ZnO:Ga from simulations. We also present alpha-induced ionoluminescence emission spectra that reveal direct, red-shifted near-bandgap emission.