Pair production also can occur in the field of an atomic electron , to which considerable recoil energy is thereby imparted. The threshold for such a process is four times the rest energy of an electron, or 4mc 2 . The total pair-production cross section is the sum of the two components, nuclear and electronic.
What is pair production used for?
Pair production, in physics, formation or materialization of two electrons, one negative and the other positive (positron), from a pulse of electromagnetic energy traveling through matter, usually in the vicinity of an atomic nucleus. Pair production is a direct conversion of radiant energy to matter .
What is pair production with example?
Pair production is the creation of a subatomic particle and its antiparticle from a neutral boson. Examples include creating an electron and a positron, a muon and an antimuon , or a proton and an antiproton. Pair production often refers specifically to a photon creating an electron–positron pair near a nucleus.
Why is pair production important?
Pair production (PP), like the photoelectric effect, results in the complete attenuation of the incident photon . ... As the photon interacts with the strong electric field around the nucleus it undergoes a change of state and is transformed into two particles (essentially creating matter from energy):
Why is pair production important in radiotherapy?
In industrial radiography where high atomic number elements are irradiated, pair production can become the major attenuation process assuming the incident radiation energy exceeds 1.022 MeV .
Why pair production is not possible in vacuum?
@Lin Zhang, in the case of pair production in vacuum, it is impossible to satisfy both momentum and energy conservation , or if momentum is conserved, not so is energy. ... If you have only one photon than the QED vertex that would describe the pair production is forbidden because it violates momentum conservation.
What kind of photon is required for pair production?
What kind of photon is required for the pair production phenomenon to occur? Explanation: When a γ-ray Photon passes close to an atomic nucleus (b < R) and it possesses energy greater than 1.02 MeV , the photon is converted into electron-positron pair. This is called pair production.
Is pair production random?
When a particle and its corresponding antiparticle meet they annihilate one another. These annihilations do not occur in a purely random way however; they must obey 3 rules: the conservation of energy, the conservation of momentum and the conservation of charge.
Does pair production occurs in vacuum?
Originally Answered: why does pair production cannot occur in vacuum ? Photons, from which pairs are created, have both energy & momentum, neither of which can be zero. When a pair is created from the photon the total energy of the pair must equal the original photon energy, which is fine.
Why is there a minimum energy for pair production?
Pair production occurs only for gamma-rays of high energy. Because an electron has a rest mass equivalent to 0.511 MeV of energy, a minimum gamma-energy of 1.02 MeV is required for this pair production. ...
What is the opposite of pair production?
The opposite of Pair Production is Annihilation . When a particle meets its equivalent anti particle (eg. an electron colliding with a positron) the two, having exact opposite charges are automatically destroyed.
What is the threshold wavelength for pair production?
For photon energies below 2m0c^2, the process cannot occur; in other words, 1.02 MeV is the threshold energy for pair production.
Who discovered pair production?
Blackett and Giovanni P. S. Occhialini discovered pair production by taking photographs of electrons and positrons created from cosmic rays in a Wilson cloud chamber (Blackett and Occhialini, 1933). The answer to the question who experimentally discovered the reverse process—positron annihilation—has been less clear.
What is the main difference between pair production and pair annihilation?
Hint: Pair production is the process in which the photons fall on a nucleus and there is the formation of electron and positron pair, where positron is the charge having a mass equal to that of the electron but possess positive charge, on the other hand, annihilation is the process in which the electron and positron ...
What is the difference between Compton effect and photoelectric effect?
| Photoelectric effect Compton effect | 4. After the interaction, the photon vanishes. 4. The dispersed photon has a longer wavelength than the incident photon. |
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What is annihilation process?
In particle physics, annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles , such as an electron colliding with a positron to produce two photons.
