Discuss the half-value thicknesses ($x_{1/2}$) of the labeled materials (steel outer sleeve, rubber lining, and pressurized gas core) relative to each other.

In your answer you should:

• explain how the intensity of the transmitted X-rays affects the darkness/brightness of the film image
• explain how the physical thickness of a material layer affects the intensity of the transmitted X-rays
• compare the relative half-value thicknesses of the steel, rubber, and gas, and draw a conclusion about their appearance on the developed film.

Small, narrow fluid channels running within the rubber lining are not clearly distinguishable from the surrounding rubber on a standard X-ray scan because they have similar density.

Explain a method used to obtain a clear image of these fluid channels.