What materials are most effective for shielding against gamma radiation?

Lead and thick concrete are particularly effective for shielding against gamma radiation due to their dense atomic structure and high mass. Gamma rays are a form of electromagnetic radiation that have high energy and are highly penetrating. Materials that are effective at shielding against gamma radiation typically need to be dense and preferably have a high atomic number.

Lead is a common choice for gamma radiation shielding because of its high density and effectiveness in attenuating gamma rays. The high atomic number of lead also contributes to its ability to absorb gamma radiation effectively. Thick concrete, which contains aggregates such as sand or gravel, provides another viable option because it can be made sufficiently dense and thick to reduce gamma radiation exposure.

When compared to other materials, options like wood, aluminum, plastic, and paper are far less effective. Materials like brick and glass may offer some level of attenuation, but they do not provide the same level of protection as lead and thick concrete. Therefore, the combination of lead and thick concrete stands out as the best choice for shielding against gamma radiation.