|When a collimated beam of monoenergetic
gamma-ray photons passes through a material, the interaction processes remove
absorption or by scattering the gamma-rays away from the detector direction.
The linear attenuation coefficient :
- describes the probability of absorption occurring per unit length within the absorber
- it is also sometimes related to the density of the absorber material and called the mass attenuation coefficient.
Linear attenuation coefficients for certain gamma energies and absorber materials are
found from linear attenuation graphs.
simulation demonstrates how the absorption of gamma-ray photons varies with the
thickness of absorber material and the type of absorber material. To explore the
relationship between these parameters go to the graph plotting exercise here.
The intensity ratio is the ratio of transmitted
intensity to initial intensity (I /I0),
and is expressed as a percentage.