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Definition
| All individuals are subject to some irradiation even though they may not work with radioactivity substances. This natural source of exposure is often referred to as ____. |
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Term
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Definition
- Radioactivity of the Earth
- Small amounts of radioactivity in the soil adds to the background levels to which man is exposed.
- Main contrbution to the backround is the gamma ray dose.
- Uranium, thorium, lesser amounts K-40 and Rb-87.
- U.S. yearly average is estimated at 22 mrem (220 μSv).
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Term
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Definition
- Radiation from space cosmic rays.
- Radiation consists of two parts Primary and Secondary.
- U.S. dose rate estimated to be 34 mrem (340 μsv).
- Dose rate increase with altitude.
- Dose rate slight decrease in latitude.
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Term
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Definition
- The galactic cosmic rays come from outside our solar system and are composed mostly of positively charged particles.
- Geomagnetically trapped radiation
- Solar cosmic rays
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Term
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Definition
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- Radioactive products which are found in air in measurable amounts.
- Produced in the atmosphere by cosmic rays.
- C-14, H-3, Na-22, and Be-7.
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Term
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Definition
- Radioactivity of the human body
- Activity transferred to man by way of the food chain cycle.
- K-40 is the most abundant in man.
- U.S. annual average equivalent does 28 mrem(280 μSv).
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Term
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Definition
| The decay of U-238 proceeds to Ra-226. When Ra-226 emits an alpha as it decays, the gas Rn-222 is formed. |
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Term
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Definition
| The decay of Ra-224 results in the gaseous product Rn-220. |
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Term
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Definition
- Radioactivity of the air
- Daughter products of elements of the uranium and thorium series.
- Radon and Thoron
- Cosmogenic radionuclides
- U.S. annual average dose estimated at 226 mrem(2,260 μSv).
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Term
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Definition
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- Result from interactions which occur when primary rays reach the earth's atmosphere.
- Products that are emitted: pions, muons (hard componet), electrons and photons (soft components), protons and neutrons (nucleonic component).
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Term
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Definition
- Man-made background radiation source.
- Caused by Nuclear Explosion
- Main contribution comes from Sr-90, Cs-137, I-131, C-14, H-3.
- Minor contributions from Kr-85, Fe-55, and Pu-239.
- U.S. total does commitment, to be delivered over many generations, is 140 mrem (1400 μSv).
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Term
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Definition
| Debris which settle to the earth as the result of a nuclear blast. |
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Definition
- Man-made background radiation source
- Diagnostic X-Rays (i.e., Radiographic, fluoroscopic, computed tomography (CT or CAT), and photofluorographic.
- Nuclear medicine
- Radiation Oncology
- Average annual effective equivalent dose 300 mrem(3,000 μSv).
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Term
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Definition
| Used in medicine by two general classifications: Nuclear Medicine and Radiation Oncology. |
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Term
| Consumer Product Radiation |
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Definition
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Group I - Involves large numbers of people and the individual equivalent dose is relatively large. (i.e., tobacco products, domestic water supplies, building materials, mining and agriculture products).
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Group II - Involves many people but the equivalent does is realatively or limited to a small portion of the body. (i.e., television receviers, radioluminus products, airport inspection systems.)
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Group III - Involves realtivley few people and the collective equivalent dose is small. (i.e., thorium products, check sources.)
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U.S. annual population dose is estimated at 10 mrem (100 μSv).
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Term
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Definition
- Radiation consist of prompt neutrons, gamma rays and possible exposures from contamination or environmental releases.
- Three radionuclides released during routine operations, which contribute to the population dose, are H-3, C-14, Kr-85.
- U.S. annual dose from environmental release is <1 mrem (10 μSv).
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