Pressure-controlled Cross-luminescence in Fast-response Barium Fluoride Scintillator

Scintillators are used in various fields as radiation detectors. Their properties, such as emission wavelength or decay time, depend on material. Scintillator that has ps decay time is required for time-of-flight measurement. BaF2 crystal has an ultrafast luminescence called cross-luminescence (CL) due to core-valence luminescence with a decay time of 600 ps. CL wavelength has a peak at deep or vacuum ultraviolet range, therefore, it is difficult to detect with photomultipliers. The first-principles calculation predicted the CL shifts to a longer wavelength by applying pressure to the crystal. In this research, we demonstrated the CL shift applying high pressure.