Radiation detectors are sensor devices, devices or materials used to observe and study nuclear radiation and microscopic phenomena of particles. The working principle of a radiation detector is based on the interaction of particles and matter. When a particle passes through a substance, the substance absorbs part or all of its energy to produce ionization or excitation. If a particle is charged, its electromagnetic field directly interacts with the orbital electrons of atoms in the substance. If it is γ-ray or X-ray, it first undergoes some intermediate process to produce photoelectric effect, Compton effect or electron pair, and transfer part or all of the energy to the orbital electrons of matter, and then generate ionization or excitation. For uncharged neutral particles, such as neutrons, the charged particles are generated by nuclear reactions, which then cause ionization or excitation.

The development trends of radiation detectors are as follows: ① Research on combined detectors and detection devices that can simultaneously provide a variety of information such as the position, energy, and time of incident particles. ② Make full use of the new achievements of electronic technology and computer technology to improve the accuracy, speed and utilization rate of the information analyzed and processed by the detector. Microelectronics technology is promoting the emergence of miniaturized detectors. ③ Seeking a more ideal detection medium and detection mechanism and developing a superconducting detector.

A radiation detector is to use an appropriate detection medium as a substance that interacts with particles, and convert the ionization or excitation generated by the particles in the detection medium into various forms of direct or indirect information that can be accepted by people's senses.