A particle detector, also known as a radiation detector, is a device used to , , and/or high-energy particles. These particles can be made by nuclear decay, cosmic radiation, or reactions in a particle accelerator. Particle detectors are used in particle physics, nuclear physics, and nuclear engineering. Modern detectors are also used as calorimeters to measure the energy of radiation. They can measure other things, such as the momentum, spin, or charge of the particles.