Formula 6.21
Epithermal neutron distribution (epithermal neutron flux)
Input(s)
$N_{N}$: Source Strength (neutrons/s)
$\mathrm{r}$: Distance from Source $(\mathrm{cm})$
$L_{e}$: Slowing Down Length $(\mathrm{cm})$
$D_{e}$: Epithermal Diffusion Coefficient $(\mathrm{cm})$
Output(s)
$\psi_{e}(r)$: Epithermal Neutron Flux at a Distance (r) from the Source (neutrons $/ \mathrm{cm}^{2} / \mathrm{s}$ )
Formula(s)
$$ \psi_{e}(r)=\left(\frac{N_{\mathrm{N}}}{4 * \pi * D_{e}}\right) * \frac{\exp \left(-\frac{r}{L_{e}}\right)}{r} $$
Reference(s)
Bassiouni, Z., 1994, Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4. Chapter 2, Page: 39.