\[\Sigma=n\sigma\]
Variables
Sigma[Σ]macroscopic cross section (1/m)
ntarget atom density (atoms/m³)
sigma[σ]microscopic cross section (m²)
Description
What is this formula?
This formula calculates the macroscopic cross section of a material by combining the microscopic interaction probability of individual nuclei with the density of target atoms. It represents the total interaction probability per unit path length.
When to use it
Use this formula in reactor design, neutron transport studies, shielding calculations, and radiation interaction analysis.
Example
Given:
n=6×10^28 atoms/m³
σ=2×10^-28 m²
Formula:
Σ=nσ
Substitution:
Σ=(6×10^28)(2×10^-28)
Result:
Σ=12 1/m
Applications
- Nuclear reactor calculations
- Radiation transport simulations
- Shielding analysis
- Material characterization
- Neutron interaction studies