Neutrons and neutron interactions

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Discussion Overview

The discussion revolves around the interactions of neutrons with atomic nuclei, specifically focusing on whether one or more neutrons affect these interactions differently. Participants explore the implications of neutron collisions with nuclei, the conditions under which these interactions occur, and the resulting nuclear processes.

Discussion Character

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

Main Points Raised

  • One participant expresses confusion about neutrons and their interactions with nuclei, questioning the outcomes of single versus multiple neutron impacts.
  • Another participant suggests that neutrons are not particularly puzzling, comparing their interactions to those of protons from the perspective of the strong interaction.
  • Several participants note that the simultaneous impact of multiple neutrons on a nucleus is highly unlikely, but discuss various possible outcomes such as absorption or scattering of neutrons depending on energy levels.
  • One participant emphasizes that the results of neutron interactions depend on the type and state of the initial nucleus and the energy of the neutrons, indicating that there is no universal pattern based on nuclear mass.
  • Another participant introduces the concept of the r-process and raises questions about neutron capture and decay processes, particularly in relation to specific isotopes and their stability.
  • There is a mention that the r-process does not involve helium, starting instead with nuclei around iron, which adds to the complexity of the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the likelihood and implications of multiple neutrons interacting with a nucleus. While some agree on the rarity of such events, others challenge the assumptions and explore the nuances of neutron interactions and nuclear processes, indicating that the discussion remains unresolved.

Contextual Notes

The discussion highlights limitations in understanding the conditions under which neutron interactions occur, including the dependence on nuclear types and energies, as well as the complexities of the r-process and its relation to neutron capture and decay.

Bashayer Abdullah
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TL;DR
Does one neutron or more than one make different when they interact with the nuclei?
Does one neutron or more than one make different when they interact with the nuclei? what is the result that could happen if one neutron or neutrons hit the nuclei? I'm not sure but I think the neutrons are the most confusing particles to deal with.

I wish you guys can help me

Thanks
 
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I don't know, what you are after, but neutrons are not so puzzling after all. From the point of view of the strong interaction it's (almost) just like a proton.
 
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You mean more than one neutron hitting a nucleus at the same time (within the nuclear interaction time)? That is incredibly unlikely. A nucleus can absorb two neutrons at the same, or absorb one and scatter one, scatter both, and various other options depending on the energies.
 
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mfb said:
You mean more than one neutron hitting a nucleus at the same time (within the nuclear interaction time)? That is incredibly unlikely. A nucleus can absorb two neutrons at the same, or absorb one and scatter one, scatter both, and various other options depending on the energies.
Thank you for your reply,
And yes that was exactly what I mean in my question
Do you mean the energy of the nuclei? And what about if the nuclei was light or heavy?
 
What can happen depends on the type and state of the initial nucleus and the overall energy involved (which mainly depends on the energy of the neutrons). There is no general pattern that would depend on the mass of the nucleus.
 
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mfb said:
You mean more than one neutron hitting a nucleus at the same time (within the nuclear interaction time)? That is incredibly unlikely.
Difficult, but must happens at relevant amount. Otherwise, why doesn´ t r-process terminate at He-3?
Think of it. One neutron beta decays to proton and picks up two neutrons - to triton.
And H-4 is unbound. t beta decay halflife is 12 years, far above the 10 minute half-life of neutron or of the explosive disassembly time of kilonova.
Even if a few t decay to He-3, first of all the best reaction path for neutron capture of He-3 is (n, p) back to t, not (n, γ) to α. And even if a few α do form, He-5 is unbound again.

On the other hand, if you somehow could add two neutrons at a nucleus within a nuclear interaction time... note that while He-5 is unbound, He-6 is bound (and beta active).

So how does r-process get across the long-lived neutron dripline nuclei t and α?
 
The r-process doesn't involve helium at all. It starts with nuclei around iron.
 

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