Calculator
White theme
Responsive grid
Inputs support cm, mm, m, and inches.
Example data
| Scenario | Layers | B | τ | Transmission | Transmitted flux |
|---|---|---|---|---|---|
| Fast neutrons, two-layer shield | Borated Polyethylene (5% B) (10 cm), Concrete (ordinary) (20 cm) | 1.2 | 2.55 | 0.0936979992 | 93698 n/cm²·s |
Numbers use typical ΣR defaults and are for demonstration only.
Formula used
This calculator uses the exponential attenuation model with a macroscopic neutron removal cross section (ΣR). For each layer, the optical thickness is:
τi = ΣR,i · xi
For multiple layers, optical thickness adds, and the uncollided transmission is:
T0 = e−∑τi
A buildup factor (B) can be applied to approximate scattered contribution:
T = B · T0
The transmitted flux is Φ = Φ0 · T. Half-value and tenth-value layers are:
HVL = ln(2)/ΣR, TVL = ln(10)/ΣR
ΣR depends on neutron energy and material composition. Use measured or vendor-provided values when available.
How to use
- Select Single material or Layered shield, then choose the number of layers.
- Enter the incident flux (or keep 1 to focus on transmission only).
- Pick a material for each layer; ΣR is auto-filled and can be overridden.
- Enter thickness and units for each layer.
- Optional: set a buildup factor and a target transmission to estimate last-layer thickness.
- Press Calculate to show results above the form, then export CSV/PDF.
Safety note: Neutron shielding is application-specific. Always verify with qualified experts, transport calculations, and applicable standards before construction or operation.