Radiation

 Radiation

Alpha

α particles thus have a mass of about 4 amu (6.642×10−4 g) each and a positive charge of 2.1 External radiation by α particles presents no direct health hazard because even the most energetic are stopped by the epidermal layer of skin and rarely reach more sensitive layers. A health hazard occurs when material contaminated with α-emitting radionuclides is eaten or inhaled, or otherwise absorbed inside the body, so that organs and tissues more sensitive than skin are exposed to α radiation.

Beta

    Beta radiation originates from what are classed as relatively light particles, actually electrons or positrons, which are smaller and more penetrating than alpha particles and can travel a few meters through the air. So unlike alpha, beta particles can penetrate a sheet of paper, but can easily be stopped by a thin sheet of either Perspex or aluminum. Typical beta emitters include strontium 90, technetium 99, caesium-137, carbon-14, sulfur-35, and tritium.

Gamma

Gamma rays are a form of electromagnetic radiation, whereby gamma radiation kills microorganisms by destroying cellular nucleic acid . The use of gamma radiation became more widespread in the 1980s, following concerns with the ecological and toxicological risks associated with ethylene oxide.