What Happens When a Photon Collides with a Proton in Glass?

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Discussion Overview

The discussion centers on the interaction between a photon and a proton within a slab of glass, exploring whether the photon will be absorbed and re-emitted or cause oscillation of the proton. The scope includes theoretical considerations of photon-matter interactions and the specific context of glass as a medium.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions the outcome of a photon colliding with a proton in glass, seeking clarification on whether absorption and re-emission or oscillation occurs.
  • Another participant suggests consulting Richard Feynman's "QED" for insights on photon-matter interactions, noting that photons typically do not interact with individual protons except at very high energies.
  • A further contribution states that below 1 or 2 MeV, photons primarily interact with electrons in the glass, with the interaction cross section for protons being significantly smaller. This participant references a specific article for detailed information on photon interactions in matter.
  • The same participant mentions that at energies above approximately 2 MeV, photons can produce electron-positron pairs through interactions with protons.

Areas of Agreement / Disagreement

Participants present differing views on the nature of photon interactions with protons in glass, with some indicating minimal interaction at lower energies and others suggesting potential interactions at higher energies. The discussion remains unresolved regarding the specific outcomes of such interactions.

Contextual Notes

The discussion highlights limitations in understanding photon interactions, particularly regarding energy thresholds and the dependence on the medium (glass). The complexity of photon interactions with protons versus electrons is noted but not fully explored.

cragar
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say we have a slab of glass and an incoming photon , and it hits a proton in the slab of glass , will it get absorbed and re-emitted or will it oscillate the proton , what will happen ,
Any input will be much appreciated
 
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I suggest looking at "QED" by Richard Feynman for a comprehensive view of photon matter interactions. Except for extremely high energy gamma rays, photons do not interact with individual protons.
 
Below 1 or 2 MeV, The photons interact only with the electrons in the glass. The cross section for interaction with the protons is about 3.3 million times smaller than the interactions with the electrons. Please review this article from the Review of Particle Properties from the Lawrence Berkeley Lab on the passage of particles (including photons) through matter.

http://pdg.lbl.gov/2009/reviews/rpp2009-rev-passage-particles-matter.pdf

See in particular pages 22 to 28 and Figure 27.14, which shows the interaction of photons with the electrons in the glass. Above ~ 2 MeV, the photons begin to produce electron positron pairs by scattering off the protons.

Bob S
 
thanks for the responses
 

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