High Quality Content by WIKIPEDIA articles! Neutron flux is a term referring to the number of neutrons passing through an area over a span of time. It is most commonly measured in neutrons/(cm²·s). This is drawn from the mathematical definition of flux. The neutron fluence is defined as the neutron flux integrated over a certain time period and represents the number of neutrons per unit area that passed during this time. Both within natural processes and in the experimental laboratory, neutron flux may be applied to atomic nuclei, in which nuclei are bombarded with neutrons at a steady rate. This can be used to produce different isotopes, including unstable, radioactive ones, of a given chemical element.