/sci/ - Science & Math » Thread #13594686

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Firing Neutron at a stable atom

Anonymous Thu 02 Sep 13:25:07 2021 No.13594686 View Reply Original Report

Quoted By: >>13594890 >>13595028 >>13595053 >>13596177

I have literally never been in a dedicated physics classroom. What happens when you fire a neutron at a stable atom? There was no good answers on Google and I figure some of you are highly educated.

Pic related. It's how I feel with my 2-year degree.

Anonymous

Anonymous Thu 02 Sep 2021 13:34:04 No.13594706 Report

Quoted By: >>13594940

That's how we make nuclear fusion- firing neutrons at unstable atoms, causing a shift of energy by causing electrons to jump to another nucleus.

I would assume that since the atom you are firing it at is already stable, there are not any electrons that would be willing to shift to a new nucleus. This is my assumption with a very limited psychics background, but I'm a pharma-fag so we will see if a physics nerd has another answer.

Anonymous

Anonymous Thu 02 Sep 2021 14:37:03 No.13594890 Report

Quoted By: >>13594895 >>13594940 >>13595482 >>13596294

>>13594686
3rd year Theoretical Phys undergrad here
If you assume that the neutron is absorbed by the nucleus then you can check the Segre chart (pic rel) to see if the resulting nucleus is stable, or if not, how it's likely to decay. If we lack data and want to guess if the nucleus will be more or less stable then we use the 'Semi-Empirical mass formula' to estimate the binding energy of the resulting nucleus, and see how that compares to what we started with; Wikipedia gives a decent ish explanation of where the terms come from, but it's just nuclear shell model stuff.

In terms of working out if the neutron is absorbed, then you'd have to model the potential of the nucleus and do some QM calculations to work out the likelihood of absorption of the neutron and transmission at different energies. In general, higher energy neutrons will pass 'through' a target nucleus at higher rates if it has a higher kinetic energy; but there are also resonances where it's abnormally likely to be absorbed against the trend.
I haven't really done much in the way of nuclear physics, so maybe someone else can clarify anything I've said further

Anonymous

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Anonymous Thu 02 Sep 2021 14:38:04 No.13594895 Report

Quoted By:

>>13594890
Hurr durr, here's the segre chart I forgot

Anonymous

Anonymous Thu 02 Sep 2021 14:59:02 No.13594940 Report

Quoted By: >>13595482

>>13594706
Me >>13594890 again

In nuclear physics electron transitions aren't really super important outside of some decay mechanisms
When you get to the energies involved in fusion and fission anything to do with electrons is pretty much negligible. Chemical processes (which is essentially what electron energy level transitions are) are on the order of eV whereas nuclear processes tend to deal with energies hundreds of millions of times that. The rest mass of an electron is only 500KeV so you could straight up start annihilating electrons and fusion / fission processes wouldn't even notice..

Anonymous

Anonymous Thu 02 Sep 2021 15:27:35 No.13595028 Report

Quoted By:

>>13594686
>Pic related
So, your brain fired a single neuron at a stable atom?

Anonymous

Anonymous Thu 02 Sep 2021 15:33:14 No.13595053 Report

Quoted By: >>13595188

>>13594686
This picture represents an ethical conundrum. Should people like this be euthanized?

Anonymous

Anonymous Thu 02 Sep 2021 16:15:58 No.13595188 Report

Quoted By:

>>13595053
OP here. Bro we are already living in the world where we keep people like that alive for money. That kid could have been born into infinite different situations where he would be a goner. I really don't care that people choose to keep people alive like that because I am an able bodied man that sits on my ass all day. I think about other social issues that are more pertinent to me like prostitution.

Anonymous

Anonymous Thu 02 Sep 2021 17:56:12 No.13595482 Report

Quoted By: >>13596128

>>13594890
>>13594940
What could you jacket a hydrogen bomb with besides steel (inert), uranium (more energy but dirty) or cobalt (if you hate things)?
Could you get more clean fusion type explosive power by using Boron or some other light material that has an interaction with the fast fusion neutrons?

Anonymous

Anonymous Thu 02 Sep 2021 20:59:39 No.13596128 Report

Quoted By:

>>13595482
If we're talking about a jacket, then I'm not sure if you'd be able to get any more fusion processes happening owing to the lack of high pressure outside of the bomb casing... If you mean just converting the neutron k.e into more radiative energy then I honestly don't know. There's really no need to make fusion bombs any more lethal in that respect though.

To my knowledge, people were actually more concerned with the opposite - getting more neutron flux and less kaboom to kill people with longer range acute radiation doses, although I don't know how you'd get that off the top of my head.

We have a module next year just on Fusion energy since they want to groom us for ITER etc, but I don't think they'll go over bombs at all (and I'm not doing it anyway :P)

To answer your original question, try looking up material science journals on neutron embrittlement and that sort of thing, there's a lot of crystals that do weird shit when they get bombarded with neutrons

Anonymous

Anonymous Thu 02 Sep 2021 21:14:22 No.13596162 Report

Quoted By: >>13596198

Is there any repelling force between the stable atom and the neutron, even minutely in say the weak force or maybe their respective casimir force cross sections?

Anonymous

Anonymous Thu 02 Sep 2021 21:21:45 No.13596177 Report

Quoted By:

>>13594686
Depends, sometime they scatter, sometimes they get absorbed by the nucleus, sometime they cause fission like Lithium 7

Anonymous

Anonymous Thu 02 Sep 2021 21:29:43 No.13596198 Report

Quoted By: >>13596258

>>13596162
QFT is beyond me at the moment so I wouldn't know about any of that, but I'm pretty sure it's not going to be anywhere close to the scale of the strong force so eh

Anonymous

Anonymous Thu 02 Sep 2021 21:53:11 No.13596258 Report

Quoted By: >>13596290 >>13596296

>>13596198
Is there anything nonzero at all though?

Anonymous

Anonymous Thu 02 Sep 2021 22:05:56 No.13596290 Report

Quoted By:

>>13596258
I haven't been taught about the casmir effect or anything like it yet, so I couldn't comment on that. Outside of that I don't think there's any contribution to the potential other than the strong force for neutrons, not that I've been taught yet anyway.
I don't think anyone is concerned enough to ever account for it that I've seen

Anonymous

Anonymous Thu 02 Sep 2021 22:10:19 No.13596294 Report

Quoted By: >>13596301

>>13594890
WTF is a 3rd year undergrad theoretical physicist? You are just a college kid

Anonymous

Anonymous Thu 02 Sep 2021 22:13:20 No.13596296 Report

Quoted By: >>13596372

>>13596258
At the quantum level there are not really forces, only particle scattering which simply means transition probabilities. A force would be seen as a transition to states with different momentum, exchanged among many particles. All exchanges are possible as long as total momentum is preserved, you can see things like 2 electrons having some small probability of being attracted, just a smaller chance than being repelled.

Anonymous

Anonymous Thu 02 Sep 2021 22:16:01 No.13596301 Report

Quoted By:

>>13596294
A college kid in the final year of my degree close to the specific topic that OP asked about. Theoretical physics PhDs have better things to do hopefully

Anonymous

Anonymous Thu 02 Sep 2021 22:47:52 No.13596372 Report

Quoted By: >>13598126

>>13596296
Different anon, ignoring the strong force and gravity, if the force between two neutrons zero or nonzero? Like does the electromagnetic field of the quarks have a microscopic effect?

Anonymous

Anonymous Fri 03 Sep 2021 09:33:29 No.13598126 Report

Quoted By:

>>13596372
I dont know any QCD, only QED. I have been told QCD is very easy if you know QED already, its just the same ideas techniques but with different symmetries and so on.
However i will say that since neutrons are compound particles, like an atom, the real interactions are among the quarks, there is likely to be interactions of all forces among neutrons, just like there are also interactions among neutral atoms such as when two neutral hydrogen atoms can still interact electrically and form an H2 molecule.
Even photons, that dont carry any charge whatsoever, interact with each other (a non classical effect, its not wave interference), two photons can exchange momentum and change their trajectories, unrelated to gravity just in QED. Neutrons likely have asymmetrical electric fields near them that are only zero far enough .

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