Basic Calculations for Occupational Safety and Environmental Health Professionals - Mathematics and Statistics for the Environment - page 440

• Clothing and turnout gear provide some protection against most beta radiation. Turnout
gear and dry clothing can keep beta emitters off of the skin.
• Exposure to beta radiation can be external or internal. External beta radiation hazards are
primarily skin burns. Internal beta radiation hazards are similar to alpha emitters.
15.9.5.1 Beta Detection Instrumentation
The types of equipment used to evaluate beta radiation in the workplace include
• Geiger-Mueller counter
• Gas proportional devices
• Scintillators
• Ion chambers
• Dosimeters
15.9.5.2 Shielding for Beta Radiation
Shielding for beta radiation is best accomplished by using materials with a low atomic number (low
z materials) to reduce Bremsstrahlung radiation (i.e., secondary x-radiation produced when a beta
particle is slowed down or stopped by a high-density surface). The thickness is critical to stop maxi-
mum energy range, and varies with the type of material used. Typical shielding materials include
lead, water, wood, plastics, cement, Plexiglas, and wax.
15.9.6 g amma r adiation and x-r ays
Gamma radiation and x-rays are used for sterilization of food and medical products; radiography of
welds, castings, and assemblies; gauging of liquid levels and material density; oil well logging; and
material analysis. The characteristics of gamma radiation and x-rays are listed below:
• Gamma (γ) radiation and x-rays are highly penetrating elecromagnetic radiation.
• X-rays are composed of photons (generated by electrons leaving an orbit).
• Gamma radiation and x-rays are electromagnetic radiation like visible light, radiowaves,
and ultraviolet light. These various types of electromagnetic radiation differ only in the
amount of energy they have. Gamma rays and x-rays are the most energetic of these.
• Gamma radiation is able to travel many meters in air and many centimeters in human tis-
sue. It readily penetrates most materials and is sometimes called penetrating radiation .
• X-rays are also penetrating radiation.
• Radioactive materials that emit gamma radiation and x-rays constitute both an external and
internal hazard to humans.
• 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.
• Gamma radiation is detected with survey instruments, including civil defense instruments.
Low levels can be measured with a standard Geiger counter, such as the CDV-700. High
levels can be measure with an ionization chamber, such as the CDV-715.
• Gamma radiation or x-rays frequently accompany the emission of alpha and beta radiation.
• Instruments designed solely for alpha detection (such as an alpha scintillation counter) will
not detect gamma radiation.
• Pocket chamber (pencil) dosimeters, ilm badges, thermoluminescent, and other types of
dosimeters can be used to measure accumulated exposure to gamma radiation.
• The principal health concern associated with gamma radiation is external exposure by
penetrating radiation and physically strong source housing. Sensitive organs include the
lens of the eye, the gonads, and damage to the bone marrow.