Delta ray
Type of radiation
A delta ray is a secondary electron with enough energy to escape a significant distance away from the primary radiation beam and produce further ionization. The term is sometimes used to describe any recoil particle caused by secondary ionization. The term was coined by J. J. Thomson.
01Characteristics
A delta ray is characterized by very fast electrons produced in quantity by alpha particles or other fast energetic charged particles knocking bound electrons out of atoms. Collectively, these electrons are defined as delta radiation when they have sufficient energy to ionize further atoms through subsequent interactions on their own. Delta rays appear as branches in the main track of a cloud chamber (See Figs. 1,2). These branches will appear nearer the start of the track of a heavy charged particle, where more energy is imparted to the ionized electrons.
02Delta rays in particle accelerators
Otherwise called a knock-on electron, the term "delta ray" is also used in high energy physics to describe single electrons in particle accelerators that are exhibiting characteristic deceleration. In a bubble chamber, electrons will lose their energy more quickly than other particles through Bremsstrahlung and will create a spiral track due to their small mass and the magnetic field. The Bremsstrahlung rate is proportional to the square of the acceleration of the electron.
03Epsilon ray
An Epsilon ray or Epsilon radiation is a type of tertiary radiation. Epsilon rays are a form of particle radiation and are composed of electrons. The term was coined by J. J. Thomson, but is very rarely used nowadays.
Sources and credits
This article is adapted from the Wikipedia article “Delta ray”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Nuclear particle in a diffusion cloud chamber.png by Cloudylabs, CC BY-SA 3.0
- Delta electron.png by Wilcokoppert, CC BY-SA 3.0
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