Something which scintillates.
In high energy/particle physics, a material that emits light when it absorbs energy from passing radiation. Scintillators (or scintillation detectors) have two main uses:
There are two basic types of scintillators with inherently different ways of converting the energy from an incoming particle
In an organic scintillator, traces of an organic scintillating material are placed in a transparent material, either liquid or plastic. Passing radiation excites single scintillator molecules which then release this energy as light.
An inorganic scintillator consists of a crystal, sometimes doped (or activated) with traces of another material. In this case, electronic states of the crystal lattice are excited by the passing radiation and, again, this energy is then released in the form of light.
In both cases, the light from the scintillator needs to be guided to a photodetector, often by a light guide or a fiber-optic wire. The photodetector, often a photomultiplier tube, then converts this light into an electrical signal.