Inorganic scintillators

Recent advances, challenges, and opportunities of inorganic nanoscintillators

This review article highlights the exploration of inorganic nanoscintillators for various scientific and technological applications in the fields of radiation detection, bioimaging, and medical theranostics. Various aspects of nanoscintillators pertaining to their fundamental principles, mechanism, structure, applications are briefly discussed. The mechanisms of inorganic nanoscintillators are explained based on the fundamental principles, instrumentation involved, and associated physical and chemical phenomena, etc. Subsequently, the promise of nanoscintillators over the existing single-crystal scintillators and other types of scintillators is presented, enabling their development for multifunctional applications. The processes governing the scintillation mechanisms in nanodomains, such as surface, structure, quantum, and dielectric confinement, are explained to reveal the underlying nanoscale scintillation phenomena. Additionally, suitable examples are provided to explain these processes based on the published data. Furthermore, we attempt to explain the different types of inorganic nanoscintillators in terms of the powder nanoparticles, thin films, nanoceramics, and glasses to ensure that the effect of nanoscience in different nanoscintillator domains can be appreciated. The limitations of nanoscintillators are also highlighted in this review article. The advantages of nanostructured scintillators, including their property-driven applications, are also explained. This review article presents the considerable application potential of nanostructured scintillators with respect to important aspects as well as their physical and application significance in a concise manner.

Absolute Luminescence Efficiency of Europium-Doped Calcium Fluoride (CaF2:Eu) Single Crystals under X-ray Excitation

The absolute luminescence efficiency (AE) of a calcium fluoride (CaF2:Eu) single crystal doped with europium was studied using X-ray energies met in general radiography. A CaF2:Eu single crystal with dimensions of 10 × 10 × 10 mm3 was irradiated by X-rays. The emission light photon intensity of the CaF2:Eu sample was evaluated by measuring AE within the X-ray range from 50 to 130 kV. The results of this work were compared with data obtained under similar conditions for the commercially employed medical imaging modalities, Bi4Ge3O12 and Lu2SiO5:Ce single crystals. The compatibility of the light emitted by the CaF2:Eu crystal, with the sensitivity of optical sensors, was also examined. The AE of the 10 × 10 × 10 mm3 CaF2:Eu crystal peaked in the range from 70 to 90 kV (22.22 efficiency units; E.U). The light emitted from CaF2:Eu is compatible with photocathodes, charge coupled devices (CCD), and silicon photomultipliers, which are used as radiation sensors in medical imaging systems. Considering the AE results in the examined energies, as well as the spectral compatibility with various photodetectors, a CaF2:Eu single crystal could be considered for radiographic applications, including the detection of charged particles and soft gamma rays.