Alpha Particles

Alpha particles generally pose little threat outside the body. They do not travel far, and they are easily absorbed or stopped by an inch or less of air or a thin barrier. However, if materials emitting alpha radiation are inhaled or ingested, the effects can be very damaging.

Alpha particles are heavy compared to other forms of radiation - about 7,300 times the mass of an electron. These large and heavy particles rapidly lose their energy when they interact with other atoms, making them effective only for a short distance.

Outside the body, alpha particles are not very forceful - they are unable to even penetrate a thin piece of tissue or the layer of dead cells at the surface of the skin. Inside the body, however, alpha particles can do great damage, disrupting living cells and killing them. Examples of radioactive materials that emit alpha particles are radium and plutonium.

To learn more about Ionizing Radiation visit our Ionizing Radiation Safety Online Training web page.