The Properties of X-Rays

The X-ray was discovered by Wilhelm Conrad Rontgen in 1895. Rontgen received the first Nobel Prize in Physics for his discovery. Next to gamma rays, X-rays have the shortest wavelength of the entire electromagnetic spectrum. It is because of their short wavelength that X-rays have high energy. Although both X-rays and gamma rays are, in theory, the same energy as light rays, their effect is much different. Like gamma rays, X-rays have the ability to penetrate matter. According to the Australian Government website, X-rays are produced by accelerating electrons through a voltage drop and directing them onto a target.

How They Travel

• X-rays are invisible to humans and consist of the same type of transverse electromagnetic vibrations as light waves. In free space, X-rays travel in a straight line at 3x108 meters per second, which is the same speed as light.

Properties of Movement

• Like light waves, X-rays can be reflected and refracted. Diffraction, the result of waves bending around obstacles or spreading out past small openings, occurs with X-rays, especially with crystalline structures. Polarization also occurs with X-rays, which means all vibrations on the wave happen on a single plane. All these properties, while similar to light waves, happen to a much smaller degree than light. Specific media have distinctive effects on how X-rays are absorbed or scattered.

Properties of Energy

• The energy of an X-ray is between 1 kiloelectronvolt (KeV) and 50 megaelectronvolts (MeV). When the high-energy electrons of X-rays interact with matter, non-destructive inspection method (NDI) X-ray images are produced. Most of the kinetic energy of X-ray's electrons is converted into heat, with actually less than 1 percent converted into X-rays. When X-rays encounter any medium, they are partially absorbed and partially transmitted.

Continuous Spectrum

• A phenomenon known as continuous X-ray spectrum happens when the electrons decelerate as they hit the target. This can be known as "bremsstrahlung," which is German for breaking radiation, or as polychromatic, continuous or white radiation. Some X-ray electrons lose all energy when colliding with the target.

Effects on Matter

• X-rays can activate fluorescent and phosphorescent properties in some elements. It can also darken photographic film. As well, X-rays can change electrical properties of some solids and liquids. In humans, X-rays can damage and kill cells as well as cause genetic mutations. It is for this reason that the utmost protection is utilized when an X-ray image is performed.