This paper presents new developments in inorganic scintillators widely used for radiation detection. It addresses major emerging research topics outlining current needs for applications and material sciences issues with the overall aim to provide an up-to-date picture of the field. While the traditional forms of scintillators have been crystals and ceramics, new research on films, nanoparticles and micro- structured materials is discussed as these material forms can bring new functionalitiy and therefore find applications in radiation detetction. The last part of the contribution reports on the very recent evolutions of the most advanced theories, methods and analyses to describe the scintillation mechanisms.

We employ a combination of first-principles calculations and optical characterization experiments to explain the mechanism by which Ga${}^{3+}$ doping prevents the trapping of free carriers due to shallow traps in RE${}_3$Al${}_5$O${}_{12}$ garnet scintillators (where RE represents a $3+$ rare-earth cation). Specifically, we confirm that Ga${}^{3+}$ doping does not reduce the defect concentration (defect engineering), but rather leads to shifts in the valence and conduction bands such that the energy level of shallow defects is no longer in the forbidden gap where electrons can be trapped (band-gap engineering).