Title: microscopic cross-section
Long Title: IUPAC Gold Book - microscopic cross-section
DOI: 10.1351/goldbook.M03911
Status: current
Index: quantity

Definition
A measure of the probability of a specified interaction or reaction between an incident radiation and a target particle or system of particles. It is the reaction rate per target particle for a specified process divided by the flux of the incident radiation. In general, a specification is added of the type of radiation (e.g. neutron, photon), the energy of the incident radiation (e.g. thermal, epithermal, fast) and the type of interaction of reaction (e.g. activation, fission, scattering).

Related Terms
- activation: https://goldbook.iupac.org/terms/view/A00103
- energy: https://goldbook.iupac.org/terms/view/E02102
- fission: https://goldbook.iupac.org/terms/view/N04229
- flux: https://goldbook.iupac.org/terms/view/F02461
- macroscopic cross-section: https://goldbook.iupac.org/terms/view/M03674
- neutron: https://goldbook.iupac.org/terms/view/N04116
- probability: https://goldbook.iupac.org/terms/view/P04855
- scattering: https://goldbook.iupac.org/terms/view/S05487

Sources
- Orange Book, 2nd ed., p. 217 (https://media.iupac.org/publications/analytical_compendium/)
- PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2517 (https://doi.org/10.1351/pac199466122513)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/M03911/html
- json: https://goldbook.iupac.org/terms/view/M03911/json
- xml: https://goldbook.iupac.org/terms/view/M03911/xml

Citation: Citation: 'microscopic cross-section' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.M03911
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Accessed: 2026-08-09T15:01:14+00:00