Nuclear Cross Section Calculator

Target Nucleus

Incident Particle (Optional)

Target Material (Optional)

About Nuclear Cross Sections

The nuclear cross section quantifies the probability of a nuclear reaction occurring. It has dimensions of area, typically measured in barns (1 b = 10⁻²⁴ cm²).

Key Formulas:

• R = r₀ × A^(1/3) where r₀ ≈ 1.2 fm
• σgeom = π × R²
• I/I₀ = exp(-nσx) (attenuation)
• λ = 1/(nσ) (mean free path)

Cross Section Units:

• 1 barn (b) = 10⁻²⁸ m² = 10⁻²⁴ cm²
• 1 millibarn (mb) = 10⁻³ b
• 1 microbarn (μb) = 10⁻⁶ b