Encyclopedia of Astrobiology

2015 Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James (Jim) CleavesII, Daniele L. Pinti, José Cernicharo Quintanilla, Daniel Rouan, Tilman Spohn, Stéphane Tirard, Michel Viso

Radiation Dose

Reference work entry
DOI: https://doi.org/10.1007/978-3-662-44185-5_1333


Ionizing radiation is measured in the SI (International System of Units, abbreviated “SI” from the French Le Système International d’Unités as the modern metric system of measurement)-derived unit of absorbed dose per mass unit, the gray (Gy), with 1 Gy equal to the net absorption of 1 J in 1 kg of material (water), compared to the previously used radiation unit “rad”, 1 Gy = 100 rad. The biological effectiveness of radiation largely depends on the local energy distribution in the target material, the  Linear Energy Transfer (LET). The quality factor Q is the biological weighting function of ionizing radiation in relation to the LET of the radiation. The product of Q and the absorbed dose is the dose equivalent. The SI-derived unit for the dose equivalent is the sievert (Sv).

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© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.DLR German Aerospace CenterInstitute of Aerospace Medicine, Radiation BiologyKölnGermany