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 Loewenthal Moisés Ville, the first colony of the JCA. It has been proven by banking records that Lowenthal died in Berlin two years later, after leaving Brussels. In the colony, Lowenthal's name graces the principal thoroughfare. Wilhelm Loewenthal Wolff Wilhelm Lowenthal ( – ) was a Polish-born, naturalized French Doctor of Medicine. Born in Rybnik, Poland, after graduating from the University of Berlin, Lowenthal (or Löwenthal, with the umlaut), went to the Caucasus to continue his medical research. At the same time, he was Professor at the University of Geneva, in its branch at the Lausanne, Switzerland. He corresponded regularly with