Does light interact with an atomic nucleus

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    Atomic Light Nucleus
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Discussion Overview

The discussion centers around the interaction of photons with fully ionized atoms, particularly protons, and whether these interactions result in energy absorption or other changes. Participants explore various aspects of nuclear interactions, including the role of electromagnetic waves in particle accelerators and phenomena such as pair production.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that fully ionized atoms, such as protons, interact with photons, particularly in the context of particle accelerators where RF waves are used.
  • Others argue that nuclear interactions primarily involve high-energy photons, such as gamma rays.
  • A participant questions whether the interaction implies energy absorption or merely a change in momentum, indicating a need for clarification on the nature of these interactions.
  • One participant mentions pair production as a specific interaction that occurs at high energies, requiring a nucleus for momentum balance.
  • Another participant references historical methods of acceleration, noting the limitations of early DC accelerators compared to modern RF systems.

Areas of Agreement / Disagreement

Participants express differing views on the nature of photon interactions with atomic nuclei, particularly regarding energy absorption versus momentum change. The discussion remains unresolved with multiple competing perspectives on the topic.

Contextual Notes

Participants highlight the complexity of interactions and the need for precise definitions, particularly regarding what constitutes an "interaction" and the conditions under which different types of photon interactions occur.

Who May Find This Useful

This discussion may be of interest to those studying nuclear physics, particle physics, or anyone curious about the interactions between light and matter at the atomic level.

KitK
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Greetings,


I was wondering if a fully ionized atom would interact with a photon. Id expect so but can't seem to find any info about it.

Thanks!
Physics Novice
 
Science news on Phys.org
Nuclear interactions involve photons of gamma ray energy only.
 
KitK said:
Greetings,


I was wondering if a fully ionized atom would interact with a photon. Id expect so but can't seem to find any info about it.

Thanks!
Physics Novice

Er... protons, which are "fully ionized" hydrogen atoms, are accelerated in particle accelerators using RF, which is an electromagnetic wave, i.e. photons. This is what is done at the Tevatron, LHC, etc. So yes, photons do interact with atomic nucleus.

Zz.
 
Thanks for the quick reply mathman! Can you eleborate on that or point me in a direction to find out more? Does the energy simply go into a change in momentum? Discrete energys absorbed? Many many questions and not sure where to find the answers.

Thanks again
 
Zapper Z

I always thought of that more as surfing the wave. My poorly composed question was more along the lines of whether thay actually absorb the energy. Of course that may be the case and the "surfing' analogy should go in the wastbasket.

Thanks
 
ZapperZ said:
Er... protons, which are "fully ionized" hydrogen atoms, are accelerated in particle accelerators using RF, which is an electromagnetic wave, i.e. photons. This is what is done at the Tevatron, LHC, etc. So yes, photons do interact with atomic nucleus.

Zz.

Zapper, what exactly do you mean? Are they shooting radio wave photons at these protons, or applying a high voltage to part of the accelerator, or what exactly?
 
KitK said:
Zapper Z

I always thought of that more as surfing the wave. My poorly composed question was more along the lines of whether thay actually absorb the energy. Of course that may be the case and the "surfing' analogy should go in the wastbasket.

Thanks

I can't read minds. All you asked for is if photons INTERACTS with atomic nuclei. Being accelerated by such RF is a clear example that it does.

Drakkith said:
Zapper, what exactly do you mean? Are they shooting radio wave photons at these protons, or applying a high voltage to part of the accelerator, or what exactly?

"RF" is a broad spectrum. I accelerate electrons using 1.3 GHz RF.

There aren't that many "DC" accelerator, i.e. where they apply static fields. Most accelerating structure, and certainly the ones at major accelerators, use RF sources, mainly out of Klystrons.

Zz.
 
I see. Alright, thanks Zapper.
 
Zapper Z,
Clearly it does.
Can you address "My poorly composed question was more along the lines of whether thay actually absorb the energy. Of course that may be the case and the "surfing' analogy should go in the wastbasket." ?

Thanks for your time. Ill bet you could read minds in a pinch.

Kitk
 
  • #10
Thanks all. Got some clarity on the subject. It help that I refined my search a bit and relearned about arxiv.org. Thanks for the prompting on your blog Zapper
 
  • #11
ZapperZ said:
I can't read minds. All you asked for is if photons INTERACTS with atomic nuclei. Being accelerated by such RF is a clear example that it does.



"RF" is a broad spectrum. I accelerate electrons using 1.3 GHz RF.

There aren't that many "DC" accelerator, i.e. where they apply static fields. Most accelerating structure, and certainly the ones at major accelerators, use RF sources, mainly out of Klystrons.

Zz.

On a historical note, the early accelerators used DC from a Van der Graaff generator. A blistering 1MeV or thereabouts!
 
  • #12
sophiecentaur said:
On a historical note, the early accelerators used DC from a Van der Graaff generator. A blistering 1MeV or thereabouts!

Yes, but that's why they are no longer used for most major accelerators. You just can't get the high gradients you need with such configuration.

Zz.
 
  • #13
I assumed interact meant a reaction where an actual change takes place, not simply a change in energy.
 
  • #14
Mathman,

Exactly what I was trying to ask, but note asking it very well :-)

Thanks again
 
  • #15
There are at least two situations which may be the kind of thing you are asking about.
1) Pair production - at high energies (above 1.022 Mev) photons, in the presence of a nucleus - needed for momentum balance, can transform into electron-positron pairs.

2) See following reference:
http://www.sbfisica.org.br/bjp/files/v37_679.pdf
 
  • #16
Mathman,

Excellent! Just the kind of thing I was looking for. I appreciate you taking the time to find the reference.

KitK
 

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