Ce:BaF2

Ce: BaF₂ crystal (also known as cerium-doped barium fluoride crystal) is a crystal with the fastest decay time and is widely used in scientific research and industrial high-energy ray detection. The fast components of pure BaF₂ crystals are concentrated in the peaks of 195nm and 220nm, and the decay time is about 800ps. In addition, there is a slow component with the peak of the emission spectrum near 310nm, and the decay time is about 600ns. The introduction of cerium ions（Ce3⁺） can effectively suppress slow components and improve the performance of the crystal.

Ce: BaF₂ crystal shows stable physical and chemical properties, with a density of 4.83g/cm³, strong blocking ability, and a radiation length of about 2.05cm. These advantages are traditionally made it better than scintillation crystal of NaI. At the same time, the refractive index of BaF₂ is close to that of optical glass, which makes it easier to export light in coupling with the photomultiplier tube. Ce: LuAG crystals are widely used in the detection of high-energy particles, such as β-rays and γ-rays. The large-sized Ce:BaF₂ crystal has been used as a traditional scintillator for gamma-ray detection and frontal X-ray imaging. However, Ce: BaF₂ crystal also has two shortcomings. The first is that its light yield is much lower than that of NaI; the second is that the emission wavelength of BaF₂ crystal is in the ultraviolet region, and it needs to be equipped with more expensive ultraviolet photomultipliers in use.