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Displayed background gamma radiation level is 9.8 μR/h (0.82 mSv/a) This is very close to the world average background radiation of 0.87 mSv/a from cosmic and terrestrial sources. Cloud chambers used by early researchers first detected cosmic rays and other background radiation. They can be used to visualize the background radiation
"The quantity dose equivalent H is the product of the absorbed dose D of ionizing radiation and the dimensionless factor Q (quality factor) defined as a function of linear energy transfer by the ICRU" H = Q × D [4] The value of Q is not defined further by CIPM, but it requires the use of the relevant ICRU recommendations to provide this value.
Recognized effects of higher acute radiation doses are described in more detail in the article on radiation poisoning.Although the International System of Units (SI) defines the sievert (Sv) as the unit of radiation dose equivalent, chronic radiation levels and standards are still often given in units of millirems (mrem), where 1 mrem equals 1/1,000 of a rem and 1 rem equals 0.01 Sv.
Background radiation is from naturally radioactive materials and cosmic radiation from space. [5] People are exposed to this radiation from the environment continuously, with an annual dose of about 3 mSv. [5] Radon gas is a radioactive chemical element that is the largest source of background radiation, about 2mSv per year. [17]
"The survey results indicate that most of the site is consistent with normal background radiation levels, but 10 locations showed elevated readings," a CDPH spokesperson said. "Our initial ...
The roentgen or röntgen (/ ˈ r ɛ n t ɡ ə n,-dʒ ə n, ˈ r ʌ n t-/; [2] symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays, and is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air (statcoulomb per kilogram).
It is often indicated in micrograys per hour (μGy/h) [1] or as an equivalent dose rate Ḣ T in rems per hour (rem/hr) or sieverts per hour (Sv/h). [ 2 ] [ 3 ] Dose and dose rate are used to measure different quantities [ 1 ] in the same way that distance and speed are used to measure different quantities.
The deterministic effects that can lead to acute radiation syndrome only occur in the case of high doses (> ~10 rad or > 0.1 Gy) and high dose rates (> ~10 rad/h or > 0.1 Gy/h). A model of deterministic risk would require different weighting factors (not yet established) than are used in the calculation of equivalent and effective dose.