Guidance for Radiation Accident Management, REAC/TS


Definition of Radiation



Safety Around Radiation Sources

Types of Radiation Exposure

Managing Radiation Emergencies

Basics of Radiation

Characteristics of Gamma Radiation and X-Rays

1. Gamma radiation and X-rays are electromagnetic radiation like visible light, radio waves, and ultraviolet light. These electromagnetic radiations differ only in the amount of energy they have. Gamma rays and X-rays are the most energetic of these.

2. Gamma radiation is able to travel many meters in air and many centimeters in human tissue. It readily penetrates most materials and is sometimes called "penetrating radiation."

3. X-rays are like gamma rays. They, too, are penetrating radiation.

4. Radioactive materials that emit gamma radiation and X-rays constitute both an external and internal hazard to humans.

5. Dense materials are needed for shielding from gamma radiation. Clothing and turnout gear provide little shielding from penetrating radiation but will prevent contamination of the skin by radioactive materials.

6. Gamma radiation is detected with survey instruments, including civil defense instruments. Low levels can be measured with a standard Geiger counter, such as the CD V-700. High levels can be measured with an ionization chamber, such as a CD V-715.

7. Gamma radiation or X-rays frequently accompany the emission of alpha and beta radiation.

8. Instruments designed solely for alpha detection (such as an alpha scintillation counter) will not detect gamma radiation.

9. Pocket chamber (pencil) dosimeters, film badges, thermoluminescent, and other types of dosimeters can be used to measure accumulated exposure to gamma radiation.