Radiation Attenuation & Shielding Calculator

This tool calculates how the intensity of gamma radiation decreases as it passes through a selected shielding material.

Select Radiation Source

Select Shielding Material

Thickness ($t$)

Results

Transmitted Ratio ($I/I_0$): 0

Absorbed Fraction ($1-I/I_0$): 0

Linear Attenuation Coeff. ($\mu$): 0 $cm^{-1}$

Underlying Principles

The attenuation of gamma rays is described by the exponential attenuation law. This principle states that the intensity of a radiation beam decreases exponentially with the thickness of the material it passes through.

$$I = I_0 e^{-\mu t} = I_0 e^{-(\frac{\mu}{\rho}) \rho t}$$

Where $I$ is the transmitted intensity, $I_0$ is the incident intensity, $\mu$ is the linear attenuation coefficient, $\rho$ is the material density, and $t$ is the thickness. The term $\mu/\rho$ is the mass attenuation coefficient, a value independent of the material's density.

Mass Attenuation Coefficients ($\mu/\rho$)

This table provides simplified mass attenuation coefficients for the gamma energies of the selected nuclides.

Source Energy (keV)	Water ($cm^2/g$)	Al ($cm^2/g$)	Fe ($cm^2/g$)	Pb ($cm^2/g$)
60	0.25	1.2	3.8	10.0
662	0.085	0.18	0.57	1.14
1250 (avg.)	0.070	0.15	0.42	0.70

Material Densities ($\rho$)

This table provides the densities used for calculation.

Material	Density ($g/cm^3$)
Water	1.0
Aluminum	2.7
Iron	7.874
Lead	11.34

Radiation Attenuation & Shielding Calculator

Results

Underlying Principles

Mass Attenuation Coefficients (\(\mu/\rho\))

Material Densities (\(\rho\))