ISPH Nuclear Energy Practice Test

Penetration describes how well radiation can pass through a material. It refers to the portion of the radiation that continues on without being stopped or absorbed, which depends on the radiation’s energy and the material’s properties (like density and composition). The higher the energy and the lower the material’s shielding effect, the greater the penetration. Absorption, by contrast, is about the radiation’s energy being taken up by the material itself, reducing the beam’s intensity. Scattering involves the radiation changing direction, which can still allow some radiation to emerge but not define the beam’s ability to pass through. Shielding is the use of material to block or greatly reduce exposure, rather than the intrinsic property of passing through. So, to describe the ability of radiation to pass through materials, the appropriate term is penetration. For context, gamma rays can penetrate concrete, while alpha particles are stopped by a sheet of paper.