ISO 31-10 - AbsoluteAstronomy.com

ISO 31-10 is the part of international standard

International standard

International standards are standards developed by international standards organizations. International standards are available for consideration and use, worldwide...

ISO 31

International Standard ISO 31 was the most widely respected style guide for the use of physical quantities and units of measurement, and formulas involving them, in scientific and educational documents worldwide...

that defines names and symbols for quantities

Physical quantity

A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement.-Definition of a physical quantity:Formally, the International Vocabulary of Metrology, 3rd edition defines quantity as:...

and units related to nuclear reaction
Nuclear reaction
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle from outside the atom, collide to produce products different from the initial particles...

s and ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

s. It gives names and symbols for 70 quantities and units. Where appropriate, conversion factors are also given.

Its definitions include:

Quantity			Unit			Remarks
Name	Symbol	Definition	Name	Symbol	Definition	Remarks
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activity	A	Expectation value of the number of spontaneous nuclear transitions from a particular energy state occurring in an amount of radionuclide in a small time interval, divided by that time interval	becquerel Becquerel The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...	Bq	1 Bq = 1/s	The becquerel is a special name for second to the power minus one, to be used as the SI unit of activity. curie Curie The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,... : 1 Ci = 3.7×10¹⁰ Bq (exactly)
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absorbed dose Absorbed dose Absorbed dose is a measure of the energy deposited in a medium by ionizing radiation per unit mass...	D	For any ionizing radiation, the mean energy imparted to an element of irradiated matter divided by the mass of this element	gray Gray (unit) The gray is the SI unit of absorbed radiation dose of ionizing radiation , and is defined as the absorption of one joule of ionizing radiation by one kilogram of matter ....	Gy	1 Gy = 1 J/kg	The gray is a special name for joule per kilogram, to be used as the SI unit for absorbed dose. rad Rad (unit) The rad is a unit of absorbed radiation dose. The rad was first proposed in 1918 as "that quantity of X rays which when absorbed will cause the destruction of the malignant mammalian cells in question..." It was defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by... : 1 rad = 0.01 Gy
dose equivalent	H	Product of D, Q and N, at the point of interest in tissue, where D is the absorbed dose, Q is the quality factor and N is the product of any other modifying factors H = D · Q · N For Q and N, see CIPM, 1984, Recommendation 1 http://www.bipm.fr/en/CIPM/db/1984/1/ and ICRU International Commission on Radiation Units and Measurements The International Commission on Radiation Units and Measurements is a standardization body set up in 1925 by the International Congress of Radiology. Its objective is to develop internationally acceptable recommendations for quantities and units of radiation and radioactivity, as well as... Report 33 (1980) http://doi.wiley.com/10.1002/jlcr.2580180918	sievert Sievert The sievert is the International System of Units SI derived unit of dose equivalent radiation. It attempts to quantitatively evaluate the biological effects of ionizing radiation as opposed to just the absorbed dose of radiation energy, which is measured in gray...	Sv	1 Sv = 1 J/kg	The sievert is a special name for joule per kilogram, to be used as the SI unit for dose equivalent. rem Röntgen equivalent man Named after Wilhelm Röntgen , the roentgen equivalent in man or rem is a unit of radiation dose equivalent... : 1 rem = 0.01 Sv
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