What material is typically used in shielding against gamma radiation?

Lead and concrete are commonly used materials for shielding against gamma radiation due to their dense properties, which are effective in attenuating high-energy photons. Gamma radiation is highly penetrating, meaning it requires materials with a substantial atomic number and mass to effectively reduce its intensity.

Lead, being a heavy metal with a high atomic number, provides significant shielding because it can absorb a large portion of the gamma rays and reduce their energy as they pass through. Similarly, concrete, although less dense than lead, can be effectively utilized for shielding, particularly in larger structures like labs or containment areas, as it can be manufactured in thick layers that enhance its protective capabilities.

While other materials like wood, plastic, glass, aluminum, water, and air can attenuate radiation, they are not nearly as effective against gamma radiation. For example, wood and plastic have lower atomic numbers and are insufficient for complete gamma protection. Likewise, while water and air can attenuate some radiation, they are not suitable for blocking significant amounts of gamma rays due to their low density and atomic composition.

Thus, lead and concrete are the preferred choices for gamma radiation shielding because they provide optimal protection.