High energy protons and electrons to gamma radiation

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Discussion Overview

The discussion revolves around the interactions of high energy protons and electrons with matter, specifically focusing on whether these particles can be absorbed and their energies emitted as photons. The scope includes theoretical considerations of particle interactions, energy emission, and the behavior of radiation in response to bombardment by these particles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that high energy protons and electrons can lead to the formation of particle showers, which include photons and other particles.
  • One participant discusses the basic interaction between electrons and protons, mentioning inverse beta decay and the conservation laws that prevent certain photon emissions from these interactions.
  • Another participant notes that high energy electrons can emit energy as photons, referred to as x-rays, which may be indistinguishable from gamma rays, but emphasizes that the electrons do not cease to exist.
  • A participant raises a question about the deflection of radiation when high energy particles strike a plate, seeking to understand the trajectory of emitted radiation and the factors that dictate deflection.
  • It is mentioned that in an x-ray tube, photons are emitted in various directions, with some being absorbed, indicating a complex interaction with the material involved.

Areas of Agreement / Disagreement

Participants express differing views on the nature of interactions between high energy protons, electrons, and photons, with some asserting that certain interactions are forbidden by conservation laws, while others focus on the emission of radiation and its characteristics. The discussion remains unresolved regarding the specifics of deflection and the overall behavior of emitted radiation.

Contextual Notes

There are limitations regarding the assumptions made about particle interactions and the definitions of terms like "photons" and "radiation." The discussion does not resolve the complexities of these interactions or the conditions under which they occur.

DarkBabylon
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Can high energy incoming protons and electrons be absorbed and their energies remitted by photons? If so what are the typical ranges of energies emitted and are they heading in the same direction as the original emission if we had a sheet of metal being bombarded by those protons and electrons?
 
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They form particle showers, including photons but also other particles. Electrons produce electromagnetic showers, protons produce hadronic showers.
 
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DarkBabylon said:
Can high energy incoming protons and electrons be absorbed and their energies remitted by photons?
the basic possible interaction between an electron and a proton is the inverse beta decay, where the result is a neutron and an electron neutrino. It also happens spontaneously within some atoms (electron capture).
In general protons and electrons cannot give just photons. Hadrons (such as protons) must be color neutral. By erasing a quark out of them (to annihilate with the electron) would result to a non-color neutral state... so indeed they give hadronic showers instead (which of course could additionally produce photons, eg the neutral pion decays). But there is a stronger reason:
Now if you say "ok, I cannot erase one thing at a time, could I erase the whole proton at once?" again the answer is no. In fact the interaction:
e + p \rightarrow \gamma + \gamma
is forbidden in the Standard Model of Particle Physics by the conservation of Lepton and Baryon Numbers...at the left hand side you have electron lepton number +1 while on the right hand side you have 0... similarily for the baryon number.
https://en.wikipedia.org/wiki/Lepton_number
https://en.wikipedia.org/wiki/Baryon_number
 
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On the other hand, high energy electrons hitting matter do emit their energy as photons, called x-rays but indistinguishable from gamma rays. They do not cease to exist, but they do stop in the electrode and are absorbed by electrode, becoming indistinguishable from the electrons that already were in Fermi sea.
 
The answers up to now are all well and good, and personally really do say where the energy goes, however I would like to know, the radiation comes from one uniform direction onto say a plate, how much deflection should we see, if occurs, as in, electrons and protons come in a velocity vector parallel to the x-axis towards the positive values of x and hit the plate, would the radiation continue the same trajectory it had before or some would be deflected?
and what dictates this deflection (not on atom by atom scale, but the material being hit as a whole)?
 
In a x-ray tube, where electron energies are small compared to rest mass of electrons and of target nuclei, photons are generally emitted in roughly all directions, and photons in unwanted directions are absorbed.
 

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