from X-rays to synchrotron light

1. The discovery of X-Rays

Wilhelm Conrad Röntgen Germany (1845-1923)

Wilhelm Röntgen was born during a time of new discoveries in physics.

There was great interest in cathode rays, electron currents emitted when a high voltage is applied between two separated pieces of metal held in an evacuated tube. In his investigations of these, he had on one occassion covered the tube in preparation for an experiment. When the voltage was applied to the tube he noticed that a phosphorescent screen lying near the tube began to glow. When the tube was turned off, the screen stopped glowing. This suggested that the screen was responding to something coming from the tube. As the specific source was unknown, Roentgen named these "x-rays".

This result intrigued him. He began to study the properties of these rays. He found that other compounds would also phosphoresce in the presence of the rays and that the rays pass through many substances but are absorbed by others. This last effect eventually led to the x-ray photographs used in medical and dental diagnosis.

For the discovery of x-rays and the investigation of their properties he received the first Nobel Prize in 1901.