Characteristic area related to the probability of a specified interaction or reaction between an incident nuclear radiation and a target particle or system of particles.
Notes: - Cross section is the reaction rate per target particle for a specified process divided by the flux density of the incident radiation.
- In general, the type of nuclear radiation (e.g. neutron, photon), the energy of the incident radiation (e.g. thermal, epithermal, fast (see: neutron energy)) and the type of interaction of reaction (e.g. activation, fission, scattering) are specified.
Example:
The capture cross section of \(\ce{^{10}B}\) for slow neutrons is \(\pu{200 barn}\).
Source:
PAC, 2021, 93, 69. 'Vocabulary of radioanalytical methods (IUPAC Recommendations 2020)' on page 75 (https://doi.org/10.1515/pac-2019-0302)