Definition of thermal neutron in US English:

thermal neutron


  • A neutron in thermal equilibrium with its surroundings.

    Compare with slow neutron
    • ‘The normalizing factor for exposure to alpha particles is 20, for thermal neutrons is two, for fast neutrons is 10, for protons is 10, and for beta particles is one.’
    • ‘It is usually the case in neutron activation analysis that both unknown samples and standard materials containing known elemental concentrations are irradiated with thermal neutrons in a nuclear reactor.’
    • ‘In the thermal type of power reactor, the neutrons are slowed to become thermal neutrons, and the number of fissile nuclei is less than the number consumed in fission; the ‘breeding’ process is therefore not self-supporting.’
    • ‘The reason is that nuclear fission occurs best with neutrons that move at relatively modest speeds, called thermal neutrons.’