Abstract

The detection of high-energy ionizing radiation is vital for various applications, including security screening, industrial non-destructive testing, and advanced medical imaging. This importance has led to growing global interest in improving detection technologies. Traditionally, scintillators—typically indirect-type X-ray detection materials composed of inorganic transparent crystals—convert high energy radiation into low-energy ultraviolet-visible photons. These processes often involve high temperatures and significant costs. However, recent advancements in lead-free metal-halide scintillators, particularly manganese (II)- based and copper (I)-based halides, have shown promising results. These innovative materials are notable for their high atomic numbers, tunable emission properties, minimal self-absorption, and cost-effective production. In this thesis, we aim to enhance critical scintillator performance metrics—such as light output, imaging resolution, and material identification—through the development and optimization of novel scintillation materials’ composition, structure, and light-guiding mechanisms. Key advancements include the creation of flexible high-resolution X-ray imaging films, the implementation of ultra-high-resolution imaging using pixelated columnar template scintillators, and the advancement of multi-energy X-ray imaging through telescopic scintillators. The main findings of this research are summarized as follows:  First, lead-free Cs₃Cu₂I₅ films address reabsorption and stability challenges in perovskites. These flexible films achieve 48.6 nGy s⁻¹ detection limits and 17 lp mm^-1 resolution, enabling imaging of non-planar surfaces for medical and security applications.

Second, Mn-doped Cs₃Cu₂I₅ scintillators optimize emission alignment with silicon sensors, enhancing radioluminescence. They match commercial GOS scintillators in brightness, feature a 46.4 µs decay time, and achieve 0.3 mm resolution in linear-array detectors for rapid imaging.

Third, nanoscale copper iodide cluster scintillators minimize light scattering, offering stability and high light yield (>30,000 photons MeV^-1). They achieve >30 lp mm^-1 resolution, enhancing medical and industrial imaging.

Fourth, pixelated manganese halide columnar arrays were developed to balance light output and resolution. Integrated with waveguide structures, they exhibit excellent uniformity and light confinement. X-ray imaging tests confirm ultra-high resolutions of 60.8 lp mm^-1, setting new benchmarks for metal halide scintillators.

Finally, a six-layer telescopic scintillator system integrates copper- and manganese-based materials for multi-energy X-ray imaging. By capturing distinct spectral data, it enables precise material differentiation, advancing security screening and medical diagnostics.