X-Ray Tube

Photo of X-Ray Tube

Have you ever broken an arm, leg, or hand and had to wear a cast? Or needed to go to the hospital to see if your hurting ankle was fractured or sprained? If so, we're willing to assume you have come in contact with an x-ray machine.

Like light and radio waves, x-rays are a type of electromagnetic radiation—oscillating electric and magnetic fields traveling at the speed of light. Their usefulness lies in their ability to penetrate matter. X-rays have the power to penetrate matter because of their relatively short wavelengths and high energy. The shorter the wavelength and the higher the energy of an x-ray, the deeper its ability to penetrate.

A man named Wilhelm Konard Roentgen discovered the x-ray in 1895. He began his experiments at the University of Wurzburg with an electric current flow in a partially evacuated glass tube (known as a cathode-ray tube). Roentgen noticed that, whenever the tube was in operation, a piece of barium platinocyanide in line with it gave off light. Roentgen theorized that the interaction of electrons striking the tube's glass wall formed an unknown radiation that caused the fluorescence. Roentgen could not determine how the radiation was carried through space or why it had such penetrating power. For this reason he called the radiation x- rays, taking the name from the mathematician's use of `x' to denote the unknown quantity in a problem. The formal name given the radiation is Roentgen rays, in honor of the discoverer. Roentgen received an Elliott Cresson Medal from The Franklin Institute in November of 1896 for his x-ray work.