American Society for Nondestructive Testing (ASNT) Radiographic Testing Practice Test

The term for short wavelength electromagnetic radiation produced during the disintegration of nuclei of radioactive substances is gamma radiation. Gamma rays are a form of high-energy radiation emitted by the decay of radioactive isotopes and are characterized by their very short wavelengths, which typically range from 0.01 nanometers to less than 0.1 nanometers. This energy allows gamma rays to penetrate most materials, making them useful for both medical imaging and industrial applications, including radiographic testing.

Gamma radiation arises specifically from nuclear decay processes where energy is released as the nucleus transitions to a lower energy state. Unlike other types of radiation, such as alpha and beta radiation, which consist of particles (helium nuclei and electrons, respectively), gamma rays are purely electromagnetic phenomena and are uncharged. This unique characteristic underlines their ability to traverse various materials without being significantly attenuated, making them a crucial element in non-destructive testing methods.

In contrast, alpha and beta radiation involve the emission of particles and are not classified as electromagnetic radiation. X-rays, while similar to gamma rays in being electromagnetic radiation, are typically produced by electronic transitions in atoms or by deceleration of charged particles, not by nuclear disintegration, which distinguishes them from gamma radiation.