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

  • Gerda HorneckEmail author
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