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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
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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: I1 = Intensity 1 at D1 I2 = Intensity 2 at D2 D1 = Distance 1 from source D2 = 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: • 1910.1096 , Ionizing radiation (general industry). • 1926.53 , Ionizing radiation (construction). • 1915.57 , Uses of fissionable material in ship repairing and shipbuilding. Ionizing radiation requirements for ship repairing and shipbuilding activities. • 1910.120 , Hazardous waste operations and emergency response. This HAZWOPER standard contains requirements relating to ionizing radiation at hazardous waste sites. • 1926.65 , 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 02-00-086 [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 1954. • STD 01-04-001 [STD 1-4.1], (1978, October 30).
OSHA Standards Cover • Exposure limits • Employee Monitoring • Warning signals • Signage • Material storage • Incident notification/reporting