How does radiation absorption vary with the thickness of a material?

Radiation absorption is closely related to the thickness of the material it passes through, and this relationship is approximately exponential. This phenomenon is described by Beer-Lambert law, which states that as the thickness of a material increases, the intensity of radiation that passes through it decreases at an exponential rate.

In practical terms, when radiation interacts with matter, more of the radiation is absorbed as it travels through greater thicknesses of material. This results in a rapid decline in intensity, especially at smaller thicknesses, and the rate of absorption slows as the material gets thicker. This exponential relationship means that small increases in thickness initially lead to significant reductions in transmission, which gradually taper off as thickness continues to increase.

Understanding this behavior is crucial in radiographic testing, as it impacts the choice of exposure settings and the interpretation of radiographic images based on material thickness.