How successful is pair production?

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SUMMARY

The discussion focuses on the phenomenon of pair production, specifically the creation of electron-positron pairs when photons interact with nuclei. The minimum photon energy required for this process is 1.022 MeV, with heavier nuclei increasing the likelihood of pair production. The probability of generating pairs is quantified using the concept of cross-section, which is measured in femtometer squared. The discussion also touches on the feasibility of creating proton-antiproton pairs from gamma rays, referencing a specific document for further reading.

PREREQUISITES
  • Understanding of photon energy levels, specifically 1.022 MeV for pair production.
  • Familiarity with nuclear physics concepts, particularly heavy nuclei and their properties.
  • Knowledge of cross-section as a measure of interaction probability in particle physics.
  • Basic grasp of particle-antiparticle pair production mechanisms.
NEXT STEPS
  • Research the concept of cross-section in particle physics and its applications.
  • Explore the conditions necessary for proton-antiproton pair production from gamma rays.
  • Investigate the role of photon energy in nuclear interactions and pair production rates.
  • Examine experimental setups that measure pair production probabilities in heavy nuclei.
USEFUL FOR

Physicists, researchers in particle physics, and students studying nuclear interactions will benefit from this discussion, particularly those interested in pair production and photon-nucleus interactions.

Michio Cuckoo
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when a photon interacts with a nucleus, a positron and an electron are created, provided the photo has enough energy.

But what is the probability of this occurring? If i fire 100 photons at a nucleus, how many electron-positron pairs will i create?

Also, has anyone ever succeeded in creating a proton-antiproton pair from gamma rays?
Is it possible?
 
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Michio Cuckoo said:
But what is the probability of this occurring? If i fire 100 photons at a nucleus, how many electron-positron pairs will i create?
The question is not well-defined, even if you define photon energy and the nucleus. You have to use something like "photons per area" or "nuclei per area", otherwise it depends on the beam characteristics.
Usually, this probability is expressed as cross-section with the unit of an area. You can view it like "if a photon (randomly) hits this small area, it will do pair-production".
For heavy nuclei, the cross-section is comparable to the size of the nuclei, which is some femtometer^2. However, I do not know precise values.
 

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