The history of the X-ray is really quite facinating. In fact the discovery of the X-ray was made quite by accident!
In the year 1895, a German physicist by the name of Wilhelm Roentgen, happened to be in his laboratory conducting experiments using a cathode.
The cathode ray was considered the first X-ray, and early X-rays were produced using a "Crookes Tube". A tube made of glass containing pressurized air or gas, with electrodes(anodes)protruding from one end. When a high voltage charge is directed through the tube, the electrons react and a flourescent glow lights up the anodes and the tube itself, casting a greenish, golden glow. The glow is caused by the electrons striking the glass, these electrons or cathode rays can be directed using a Crookes tube. When heated, cathodes can stream and deflect or focus a beam of light at a directed target. To demonstrate, a Crookes tube will have a small plate of metal inserted and placed between the glass and the cathode. When high voltage was applied, the cathode rays would travel in a straight line, causing an actual shadow of the plate, cast on the glow of the flourescence! The cathodes could therefore travel just as light can travel, and could be directed in streams at a desired target.
The early form of X-ray was the "Crookes Tube", a cathode or electron stream was directed and than focused on a metal target, thereby producing an X-ray. These rays were low energy waves, not as powerful as those Roentgen would soon discover.
The discovery by Roentgen was a mishap, he happened to have a messy lab and while performing experiments using the cathode rays in a "Crookes Tube" which, was enclosed in a black cardboard box; he discovered that everytime the voltage was applied to the tube, a flourescent glow would appear on an old screen laying nearby on the floor. This screen happened to be constucted of barium and platinocyanide, and upon futher experimention, Roentgen discovered that the flourescence was caused by what he called invisible rays. The rays he realized were of a much more penetrating nature than he could ever have imagined, more so than ultra-violet!
He named his discovery the X-ray because he had no idea the nature of this powerful energy source. Later is was named as the "Roentgen Ray", in honor of Wilhelm Roentgen.
Roentgen had discovered electromagnetic radiation, and Roentgen was awarded the Noble prize in 1901, for his outstanding work in physics. Wilhelm Roentgen was in fact the first to be awarded the Noble Laureate in physics.
Experiments with electromagnetic radiation were constant during the early years. It was discovered the shorter the wave length the more powerful and penetrating these rays could be. It was discovered that X-rays occur after high velocity electrons are released striking a target, much of the energy is lost but the remaining causes changes in the molecular structure of the target on impact, creating the X-ray.
A spectometer is used to direct the electromagnetic radiation, and the metal that is used to assist in the superimposing of the image is called, Tungsten. The reason Tungsten was, and is used to this day, is because Tungsten can be heated to a temperature much higher than any other metal and not melt! In fact, Tungsten melts at 6,170 degrees Fahrenheit! Amazing!
The X-ray is an important discovery and has assisted mankind in making medical history. The M.R.I. another form of magnetic imaging is a modern technique, used more frequently now in nuclear medicine and scientific studies, as well as industry. The X-ray is truly one of the great discoveries of modern mankind.