Effects
A wide range of biological changes may follow the irradiation of animals. These vary from rapid death following high doses of penetrating whole-body radiation, to essentially normal lives for a variable period of time until the development of delayed radiation effects, in a portion of the exposed population, following low dose exposures.
The unit of actual exposure is the röntgen, defined in ionisations per unit volume of air. All ionisation based instruments (including geiger counters and ionisation chambers) measure exposure. However, effects depend on the energy per unit mass, not the exposure measured in air. A deposit of 1 joule per kilogram has the unit of 1 gray (Gy). For 1 MeV energy gamma rays, an exposure of 1 röntgen in air produces a dose of about 0.01 gray (1 centigray, cGy) in water or surface tissue. Because of shielding by the tissue surrounding the bones, the bone marrow only receives about 0.67 cGy when the air exposure is 1 röntgen and the surface skin dose is 1 cGy. Some lower values reported for the amount of radiation that would kill 50% of personnel (the LD50) refer to bone marrow dose, which is only 67% of the air dose.
Read more about this topic: Nuclear Fallout
Famous quotes containing the word effects:
“The ultimate result of shielding men from the effects of folly, is to fill the world with fools.”
—Herbert Spencer (1820–1903)
“Oh that my Pow’r to Saving were confin’d:
Why am I forc’d, like Heav’n, against my mind,
To make Examples of another Kind?
Must I at length the Sword of Justice draw?
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How ill my Fear they by my Mercy scan,
Beware the Fury of a Patient Man.”
—John Dryden (1631–1700)
“Consider what effects which might conceivably have practical bearings we conceive the object of our conception to have. Then our conception of these effects is the whole of our conception of the object.”
—Charles Sanders Peirce (1839–1914)