What is the radiation-sensitive portion of a scintillation detector composed of?

The radiation-sensitive portion of a scintillation detector is composed of a light-emissive crystal. When radiation (such as gamma rays or x-rays) interacts with the scintillation crystal, it excites the crystal's atoms, leading to the emission of light in the visible spectrum. This process is known as scintillation. The emitted light is then detected and converted into an electrical signal by a photodetector (often a photomultiplier tube or photodiode).

In the context of radiation detection, the light-emissive crystal is critical because it provides the initial response to incoming ionizing radiation, which is then processed to provide measurable data about the radiation levels. Other components, such as thermal conductors, photovoltaic cells, or metal casings, may be involved in the overall construction and operation of a scintillation detector but do not perform the primary function of detecting radiation. Thus, the choice of a light-emissive crystal accurately identifies the critical component responsible for the scintillation process and the detection of radiation.