Kinetic energy of a free neutron.
Notes: - Neutron energy is usually given with unit electronvolt (\(\pu{eV}\)). \(\pu{1 eV} = \pu{1.602176634E-19 J}\).
- Neutron temperature has unit kelvin, and the term should not be used for the neutron energy.
- Neutrons are classified according to their energies as follows:
| Neutron energy range (in eV) | Name |
|---|
| 0.0-0.025 | cold neutron |
| 0.025 (corresponding to 295 K) | thermal neutron |
| 0.025-0.4 | epithermal neutron |
| 0.4-0.6 | cadmium neutron |
| 0.6-1 | epicadmium neutron |
| 1-10 | slow neutron* |
| 10-300 | resonance neutron |
| 300-1 × 106 | intermediate neutron |
| (1-20) × 106 | fast neutron |
| >20 × 106 | ultrafast neutron |
| *Slow neutron also may be defined as any neutron below a threshold which may vary over a wide range and depends on the application. In reactor physics, the threshold value is frequently chosen to be 1 eV; in dosimetry, the effective cadmium cut-off is used. See: [2]. |
Source:
PAC, 2021, 93, 69. 'Vocabulary of radioanalytical methods (IUPAC Recommendations 2020)' on page 88 (https://doi.org/10.1515/pac-2019-0302)