Ionizing Radiation
Ionizing radiation is energy in the form of waves or particles that has enough force to remove electrons from atoms. The major types of radiation emitted during radioactive decay are alpha particles, beta particles, and gamma rays. Radiation can come from natural sources or man-made radionuclides. Man-made x-rays, another type of radiation, are produced outside of the nucleus.
Ionizing radiation penetration powers.
- Alpha particles are energetic, positively charged particles consisting of two protons and two neutrons. External exposure (external to the body) is of far less concern than internal exposure, because alpha particles lack the energy to penetrate the outer dead layer of skin.
- Beta particles are fast moving electrons emitted from the nucleus during radioactive decay. Some beta particles can penetrate the skin and cause radiation damage, such as skin burns. However, as with alpha-emitters, beta-emitters are most hazardous when they are inhaled or ingested.
- Gamma rays - Like visible light and x-rays, gamma rays are weightless packets of energy called photons. Gamma rays are a radiation hazard for the entire body. While gamma rays can easily pass completely through the human body, a fraction will always be absorbed by tissue.
- X-rays are high-energy photons produced by the interaction of charged particles with matter. Literally thousands of x-ray machines are used daily in the medical and other industries for examinations, inspections, and process controls. Because of their many uses, x-rays are the single largest source of man-made radiation exposure.
Controlling Exposure
Basic Control Methods for external sources of ionizing radiation include:
- Time: Minimize time of exposure to minimize total dose. Rotate employees to restrict individual dose.
- Distance: Maximize distance to source to maximize attenuation in air.
- Shielding: Minimize exposure by placing absorbing shield between worker and source.
Knowledge Check Choose the best answer for the question.
2-9. Which of the following describes ionizing radiation?
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