scintillaatio

Scintillaatio, or scintillation, is the emission of light by a material after its absorption of ionizing radiation. The light is produced in scintillators—crystals, glasses, liquids, or plastics—that contain luminescent centers. When radiation deposits energy in the material, electrons are excited and transfer energy to these centers, which decay radiatively and emit photons typically in the UV or visible range. The emitted light is then detected by photodetectors such as photomultiplier tubes or silicon photomultipliers, converting it into an electrical signal for spectroscopy or imaging.

Key properties include light yield, the spectrum of emitted light, decay time (the time constants of the luminescence), and energy resolution. Some scintillators emit promptly; others have multiple decay components or long afterglow that can affect performance.

Common inorganic scintillators are NaI(Tl), CsI(Tl), BGO, LSO/LYSO, and LaBr3:Ce; organic and plastic scintillators are used for fast timing and large-area detectors; liquid scintillators are used in neutrino and reactor experiments. Choice depends on density, effective atomic number, transparency, decay time, and radiation hardness.

Applications span medical imaging (PET and SPECT), high-energy physics experiments, radiation monitoring and homeland security, astrophysical detectors, and industrial nondestructive testing. Scintillation detection is often paired with photodetectors and, in modern systems, with silicon photomultipliers and fast readout electronics to achieve good energy and timing resolution.