Which shielding is typically used to reduce exposure to gamma radiation?

• A. Lead shielding
• B. Paper shielding
• C. Water shielding
• D. No shielding required

Answer: (A)

Gamma rays are highly penetrating, so reducing exposure means using a material that attenuates photons effectively. Lead shielding is used for this because lead has a high atomic number and high density, giving it a large attenuation coefficient for gamma photons. The amount of gamma radiation that gets through drops roughly as I = I0 exp(-μx); with a larger μ, you achieve more shielding for a given thickness. The combination of density and high Z makes lead much more effective per unit thickness than lighter materials, so it can provide substantial protection without needing impractically thick barriers. Paper offers almost no attenuation because of its very low density, and while water can shield gamma rays, it would require a much thicker layer to match lead’s protective ability. In practice, lead shielding is the standard choice for reducing gamma exposure.