Roentgen (unit) Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays. It is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air. In 1928 it was the first international measurement quantity for ionising radiation to be defined for radiation protection, and was an easily replicated method of measuring air ionization directly by using an ion chamber. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays. Although relatively easy to measure, it had
Wilhelm Olivier Leube Wilhelm Olivier Leube Wilhelm Olivier Leube (14 September 1842 – 16 May 1922) was a German internist born in Ulm. He studied medicine in Tübingen, Zurich, Berlin and Munich, and from 1868 worked as an assistant at the medical clinic in Erlangen. In 1872, at the University of Jena, he became a professor of pathology and special therapy, as well as director of the medical clinic. At Jena, one of his assistants was noted physician Ottomar Rosenbach (1851–1907). Afterwards he was a professor at the Universities of Erlangen (1874–1885) and Würzburg, where in 1895/96 he served as university rector. Wilhelm