Skip to main content

Compton effect

Compton effect [for A. H. Compton], increase in the wavelengths of X rays and gamma rays when they collide with and are scattered from loosely bound electrons in matter. This effect provides strong verification of the quantum theory since the theoretical explanation of the effect requires that one treat the X rays and gamma rays as particles or photons (quanta of energy) rather than as waves. The classical treatment of these rays as waves would predict no such effect. According to the quantum theory a photon can transfer part of its energy and linear momentum to a loosely bound electron in a collision. Since the energy and magnitude of linear momentum of a photon are proportional to its frequency, after the collision the photon has a lower frequency and thus a longer wavelength. The increase in the wavelength does not depend upon the wavelength of the incident rays or upon the target material. It depends only upon the angle that is formed between the incident and scattered rays. A larger scattering angle will yield a larger increase in wavelength. The effect was discovered in 1923. It is used in the study of electrons in matter and in the production of variable energy gamma-ray beams.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Compton effect." The Columbia Encyclopedia, 6th ed.. . 16 Jul. 2018 <>.

"Compton effect." The Columbia Encyclopedia, 6th ed.. . (July 16, 2018).

"Compton effect." The Columbia Encyclopedia, 6th ed.. . Retrieved July 16, 2018 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.