What type of shielding is effective against alpha particles?

Alpha particles are relatively large and heavy compared to other forms of radiation, such as beta particles or gamma rays. These particles are composed of two protons and two neutrons, which makes them positively charged. Due to their size and charge, alpha particles have a limited range in materials and can be easily stopped.

Plastic or paper is particularly effective at shielding against alpha particles because these materials are sufficient to absorb the energy of the particles entirely. Even a few centimeters of air can significantly reduce the intensity of alpha radiation, and thin sheets of paper or a few millimeters of plastic can provide complete protection.

In contrast, while materials like lead, concrete, and water are effective shields against gamma radiation and, to a lesser extent, beta particles, they are not necessary for blocking alpha particles because the latter cannot penetrate even the skin effectively. Therefore, using plastic or paper is not only effective but also practical for alpha radiation shielding.