What can stop gamma radiation?

Gamma radiation is a form of high-energy electromagnetic radiation that is highly penetrating and can travel long distances through various materials. To effectively stop or shield gamma radiation, dense materials with high atomic numbers are required.

Lead and thick concrete are particularly effective because they provide significant density and atomic structure that can absorb and scatter the energy from gamma rays, thereby reducing their intensity and preventing them from passing through. The thickness and density of these materials play crucial roles in their ability to attenuate gamma radiation effectively.

Other materials, like thin metal foil, paper, and water, lack the necessary density to provide sufficient shielding against gamma rays. While they may absorb some radiation, they are not adequate as protective measures when dealing with high-energy gamma radiation. This is why lead or thick concrete is the best answer for stopping gamma radiation.