X-ray

From ArticleWorld

X-rays are electromagnetic rays of short wavelengths which can pass through opaque bodies. An important tool in many fields from medical diagnosis to machine-part inspection, X-rays can be used to capture permanent images on photographic plates. The part of an object imaged which absorbs X-rays shows up as a shadow on the plate.

The discovery of X-rays

X-rays were discovered by Wilhelm Conrad Roentgen in 1895. A professor of physics at Wurzburg University in Germany, Roentgen was experimenting with electric current flow in a gas filled tube, when he saw a mysterious glow originating from a screen coated with barium platino-cyanide. Roentgen happened to put his hand between the tube and the screen. To his surprise, he saw a clear image of the bone structure of his hand being projected on the screen. Deciding to place a photographic plate in place of the screen, the professor, who was also a keen photographer, managed to take the first known X-ray image: that of his wife’s left hand with her bones and a gold ring clearly appearing as permanent shadows. At first, since Roentgen did not know what the rays were, he simply called them ‘X-rays’.

How X-rays are produced

X-rays are produced from devices called X-ray tubes, in which electrons are accelerated to high energies and made to hit a metallic target. X-rays are subsequently emitted from the target. X-rays can be of two kinds, namely, hard X-rays and soft X-rays.

X-rays - Modern uses

Soon after their discovery, X-rays began to be used for medical diagnosis. Imaging of internal body parts could be done using X-rays, to detect bone fractures or organ damages.

Apart from medicine, X-rays today are used in detecting cracks in concrete structures at construction sites, as also in looking for defects in internal machine parts.