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
Dietrich Wilhelm Heinrich Busch Dietrich Wilhelm Heinrich Busch Dietrich Wilhelm Heinrich Busch (16 March 1788 – 15 March 1858) was a German obstetrician born in Marburg. In 1806 he earned his medical doctorate at the University of Marburg, becoming an associate professor of surgery in 1814. In 1817 he was appointed professor of obstetrics at Marburg, where from 1820 to 1829 he was director of the department of obstetrics. In 1829 he succeeded Adam Elias von Siebold (1775-1828) as professor and director of the obstetrics clinic at Friedrich Wilhelm University in Berlin, serving as university rector in 1835/36. He would remain as director of