Presentation on theme: "Ionizing Radiation Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms."— Presentation transcript:
Ionizing Radiation Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them.
Ionizing Radiation Alpha Particles: consist of two protons and two neutrons bound together into a particle Beta Particles: Beta particles are high- energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei Gamma Rays: Gamma rays are short wavelength electromagnetic radiation, not particles.
Ionizing Radiation Shielding ◦ Alpha Particles: Sheet of paper ◦ Beta Particles: Plastic shields ◦ Gamma Rays: Lead of a certain thickness
Ionizing Radiation There are four standard ways to limit exposure: ◦ Time: Limiting or minimizing the exposure time will reduce the dose from the radiation source. ◦ Distance: Radiation intensity decreases sharply with distance, according to an inverse square law. ◦ Shielding: Barriers of lead, concrete, or water give effective protection from radiation formed of energetic particles such as gamma rays and neutrons. The effectiveness of a material in shielding radiation is determined by its halve value thicknesses, the thickness of material that reduces the radiation by half. ◦ Containment: Radioactive materials are confined in the smallest possible space and kept out of the environment.
Inverse Square Law Where: I 1 = Intensity 1 at D 1 I 2 = Intensity 2 at D 2 D 1 = Distance 1 from source D 2 = Distance 2 from source
Inverse Square Law Example The radiation exposure to a person was measured at 5 mR/hour of gamma radiation when the source was located a distance of one foot away. Increasing the distance to two feet would result in an exposure of how many mR/hour?
Non-ionizing Radiation Extremely Low Frequency Radiation (ELF) ◦ Extremely Low Frequency (ELF) radiation at 60 HZ is produced by power lines, electrical wiring, and electrical equipment. Radiofrequency and Microwave Radiation Microwave radiation (MW) ◦ Radiofrequency and Microwave Radiation Microwave radiation (MW) is absorbed near the skin, while Radiofrequency (RF) radiation may be absorbed throughout the body. ◦ Sources of RF and MW radiation include radio emitters and cell phones. Infrared Radiation (IR) ◦ The skin and eyes absorb infrared radiation (IR) as heat. ◦ Sources of IR radiation include furnaces, heat lamps, and IR lasers. Visible Light Radiation ◦ The different visible frequencies of the electromagnetic (EM) spectrum are "seen" by our eyes as different colors. ◦ Excessive visible radiation can damage the eyes and skin. Ultraviolet Radiation (UV) ◦ Ultraviolet radiation (UV) has a high photon energy range and is particularly hazardous because there are usually no immediate symptoms of excessive exposure. ◦ Lasers typically emit optical (UV, visible light, IR) radiations and are primarily an eye and skin hazard.
Applicable OSHA Standards General Duty Clause 5(a)(1) Ionizing radiation falls under a variety of OSHA standards including: ◦ , Ionizing radiation (general industry). ◦ , Ionizing radiation (construction). ◦ , Uses of fissionable material in ship repairing and shipbuilding. Ionizing radiation requirements for ship repairing and shipbuilding activities. ◦ , Hazardous waste operations and emergency response. This HAZWOPER standard contains requirements relating to ionizing radiation at hazardous waste sites. ◦ , Hazardous waste operations and emergency response. This HAZWOPER standard for the construction industry; also contains requirements relating to ionizing radiation at hazardous waste sites.
OSHA Directives Memorandum of Understanding Between the OSHA and the U.S. Nuclear Regulatory Commission. CPL [CPL 2.86], (1989, December 22). ◦ Delineates the authorities, responsibilities, and other activities between OSHA and NRC for occupational health and safety at radiation sites. OSHA Coverage of Ionizing Radiation Sources Not Covered by Atomic Energy Act of ◦ STD [STD 1-4.1], (1978, October 30).