Wilhelm Conrad Roentgen


The German physicist Wilhelm Conrad Roentgen, b. Mar. 27, 1845, d. Feb. 10, 1923, discovered X rays, for which he received (1901) the first Nobel Prize for physics. He observed (1895) that barium platinocyanide crystals across the room fluoresced whenever he turned on a Crooke's, or cathode-ray discharge, tube, even when the tube, an electron emitter, was shielded by black cardboard or thin metal sheets. Roentgen correctly hypothesized that a previously unknown form of radiation of very short wavelength was involved, and that these X rays (a term he coined) caused the crystals to glow. He later demonstrated the metallurgical and medical use of X rays.