Tag: Gray

The gray (symbol: Gy) is the SI unit of absorbed radiation dose of ionizing radiation (for example, X-rays), and is defined as the absorption of one joule of ionizing radiation by one kilogram of matter (usually human tissue).
Named after the British physicist Louis Harold Gray, the SI unit replaces the traditional cgs unit, the rad (equivalent to 0.01 Gy), which remains common in industry in the United States, while “strongly discouraged” in the style guide for U.S. National Institute of Standards and Technology authors.
One gray is the absorption of one joule of energy, in the form of ionizing radiation, divided by one kilogram of matter.
For xrays and gamma rays, these are the same units as the sievert (Sv). To avoid any risk of confusion between the absorbed dose (by matter) and the equivalent dose (by biological tissues), one must use the corresponding special units, gray is used instead of the joule per kilogram for absorbed dose and the sievert instead of the joule per kilogram…