Question

What is a thermal neutron? What is its importance?

Answer 1

Thermal neutrons are any free neutron (one that is not bound within an atomic nucleus) that has an average energy of motion (kinetic energy) corresponding to the average energy of the particles of the ambient materials. They are in thermal equilibrium with a surrounding medium of temperature 290K .

Because of relatively slow and of low energy, thermal neutrons exhibit properties, such as large cross sections in fission, that make them desirable in certain chain-reaction applications. Furthermore, the long de Broglie wavelengths of thermal neutrons make them valuable for certain applications of neutron optics.