Roentgen equivalent man has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States. A number of earlier definitions going back to 1945 were derived from the roentgen unit, which was named after Wilhelm Röntgen, a German scientist who discovered X-rays. The acronym is now a misleading historical artifact, since 1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem. One rem carries with it a 0.05% chance of
David Roentgen David Roentgen David Roentgen (1743 in HerrnhaagFebruary 12, 1807), was a famous German cabinetmaker of the eighteenth century, famed throughout Europe for his marquetry and his secret drawers and mechanical fittings. His work embraces the late Rococo and the Neoclassical styles. In 1753 his father Abraham Roentgen, who had trained in London in the workshop of William Gomm, migrated to the Moravian settlement at Neuwied, near Coblenz, where he established a furniture factory. David learned his trade in his father's workshop, inherited the paternal business in 1772, and entered into partnership with the clockmaker Kintzing. By that time, the name