Neutron flux

The neutron flux is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total distance travelled by all free neutrons per unit time and volume.^[1] Equivalently, it can be defined as the number of neutrons travelling through a small sphere of radius $R$ in a time interval, divided by a maximal cross section of the sphere (the great disk area, $\pi R^{2}$ ) and by the duration of the time interval.^[2]^: 82-83 The dimension of neutron flux is ${\mathsf {L}}^{-2}{\mathsf {T}}^{-1}$ and the usual unit is cm⁻²s⁻¹ (reciprocal square centimetre times reciprocal second).

The neutron fluence is defined as the neutron flux integrated over a certain time period. So its dimension is ${\mathsf {L}}^{-2}$ and its usual unit is cm⁻² (reciprocal square centimetre). An older term used instead of cm⁻² was "n.v.t." (neutrons, velocity, time).^[3]

^ Cite error: The named reference Stamm'ler_1983 was invoked but never defined (see the help page).
^ Cite error: The named reference Beckurts_1964 was invoked but never defined (see the help page).
^ M. F. Kaplan (August 1983). Nuclear Radiation and the Properties of Concrete (PDF). University of Cape Town. p. 2. Retrieved 14 September 2022.

[Stamm'ler_1983-1] Cite error: The named reference Stamm'ler_1983 was invoked but never defined (see the help page).

[Beckurts_1964-2] Cite error: The named reference Beckurts_1964 was invoked but never defined (see the help page).

[3] M. F. Kaplan (August 1983). Nuclear Radiation and the Properties of Concrete (PDF). University of Cape Town. p. 2. Retrieved 14 September 2022.

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