Shielding design
Configure the stack
teaching model, not clinical
Current transmitted fraction, I/I₀
—
Current optical thickness, Σμx
—
Concept: Each additional half-value layer halves the remaining intensity, not the original intensity.
The maths
One slab: I/I₀ = exp(−μx).
Stack: I/I₀ = exp(−Σμᵢxᵢ).
Linearised: ln(I/I₀) = −Σμᵢxᵢ.
Half-value layer: HVL = ln(2)/μ.
Mean free path: λ = 1/μ.
Measurement: μ = −ln(I/I₀)/x.
Mass coefficient: μ = (μ/ρ)ρ.
μ: cm⁻¹; x, HVL, λ: cm; μ/ρ: cm²/g; ρ: g/cm³.
Assumption: a narrow monochromatic beam follows the exponential law through at most three homogeneous layers, with no scattering or build-up.
Live model output
Attenuation plots
Log intensity through the stack
Exponential transmission and half-values
Model
Layer boundary / HVL marker
● Current thickness
Simulation controls