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Nuclear atom


observer1
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1 hour ago, observer1 said:

Is there a particle which, when is hit with a neutron decays into another atom and releases only ONE neutron?

Decay is a spontaneous reaction, and you are describing an induced reaction or a scattering reaction 

Fission is one possibility; thermal neutron-induced fission of U-235 releases 2.43 neutrons on average, so one would expect some fraction of the fissions to release just one neutron.

For the scatter, a change into a different atom requires the ejection of a proton in addition to the neutron. A possible candidate would be something that undergoes beta+ decay, and the scatter excites the nucleus, which then decays more readily from the excited state.

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5 hours ago, observer1 said:

Is there a particle which, when is hit with a neutron decays into another atom and releases only ONE neutron?

You mean a neutron activation process in which the nucleus re-emits only a neutron, thereby returning to its former state, a bit like an atom absorbing and re-emitting a photon? I'd have thought there might be such a process, but I must admit I have not found any examples. 

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4 hours ago, swansont said:

Decay is a spontaneous reaction, and you are describing an induced reaction or a scattering reaction 

Fission is one possibility; thermal neutron-induced fission of U-235 releases 2.43 neutrons on average, so one would expect some fraction of the fissions to release just one neutron.

For the scatter, a change into a different atom requires the ejection of a proton in addition to the neutron. A possible candidate would be something that undergoes beta+ decay, and the scatter excites the nucleus, which then decays more readily from the excited state.

How do you release 2.43 neutrons ?  This suggests 2 whole neutrons, plus 1/2 a neutron.  Or is that just a silly question.

 

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10 minutes ago, paulsutton said:

How do you release 2.43 neutrons ?  This suggests 2 whole neutrons, plus 1/2 a neutron.  Or is that just a silly question.

It is a silly question.  2.43 is the average number of neutrons that are produced by the fission of U-235.

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ok so basically, a standard nuclear fission says if one neutron if fired onto an unstable atom heavy atom it splits into two lighter atoms and 2 neutrons and continues the chain reaction. I am asking if there an atom that is heavy and unstable and when hit by a neutron releases only one neutron or even close to one on average.

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3 hours ago, observer1 said:

ok so basically, a standard nuclear fission says if one neutron if fired onto an unstable atom heavy atom it splits into two lighter atoms and 2 neutrons and continues the chain reaction. I am asking if there an atom that is heavy and unstable and when hit by a neutron releases only one neutron or even close to one on average.

Thank you for the clarification.

 

Kay and Layby list one important such reaction, but theya re rather hard to find.

neutron1.thumb.jpg.8be07b99602cd6bc1912a4838b07622c.jpg

 

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20 hours ago, observer1 said:

ok so basically, a standard nuclear fission says if one neutron if fired onto an unstable atom heavy atom it splits into two lighter atoms and 2 neutrons and continues the chain reaction. I am asking if there an atom that is heavy and unstable and when hit by a neutron releases only one neutron or even close to one on average.

Some fissions of heavy nuclei will release only one neutron.

In general you will not find heavy nuclei that release only one neutron, on average, because they have a large neutron/proton ratio, so the fission fragments are very neutron-rich, so they are highly unstable and shedding the extra neutrons is energetically favorable. Sometimes the neutron emission is immediate, and often you get  the lowering of the N/Z ratio via beta decay afterwards.

To get only the one neutron out you would need to fission a much lighter nucleus (with a lower N/Z ratio), and that would require a lot of energy to be added. 

 

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8 hours ago, observer1 said:

so the more unstable the more energy it releases?

Since you were kind enough to respond to my last post the way you did I will add to Bufofrog's excellent link (+1) for as advertised it is easy to understand.

But it is not the whole story of the energy.

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On 9/14/2022 at 11:03 AM, observer1 said:

Is there a particle which, when is hit with a neutron decays into another atom and releases only ONE neutron?

Hydrogen-4 (H-4) decays to Tritium (H-3) and one free neutron.

So, if you hit Tritium (H-3) by free neutron, it could be converted to Hydrogen-4 (H-4) and after a while (ultra short), it will decay back to Tritium and emit free neutron. Giving none or subtle traces of reaction like e.g. change of path of neutron and/or little delay.

https://en.wikipedia.org/wiki/Isotopes_of_hydrogen

But it is extremely fast decay (in yoctoseconds).

"Another atom"? It must be the same type of atom as the one hit, otherwise the rules of conservation would be violated, no?

or.. can it emit something else (e.g., positron, electron, proton, alpha or whatever), besides the free neutron?

 

Free neutrons differ in their kinetic energy. That is why they are called cold/slow and hot/fast neutrons.

https://en.wikipedia.org/wiki/Neutron_temperature#Slow

https://en.wikipedia.org/wiki/Neutron_temperature#Fast

https://en.wikipedia.org/wiki/Neutron_temperature#Ultrafast

 

 

If you hit Deuterium with a free neutron with a kinetic energy greater than 2.22 MeV, it can yield a free proton and a free neutron, and your original free neutron.

 

 

Other isotopes that decay by neutron emission are He-5, He-7, He-9:

https://en.wikipedia.org/wiki/Isotopes_of_helium
 

 

Edited by Sensei
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25 minutes ago, observer1 said:

but since i have "observed" you, you have to decide which one

Well, sniff, there's all sort of dead cat in this box, so I'm going to have a guess...

Edited by dimreepr
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1 hour ago, observer1 said:

but since i have "observed" you, you have to decide which one

Even though you haven't acknowled it, I actually answered you question.

However since I also really appreciate this quip  +1  ,

I would also like to note that reactions in general expel photons and particles often at high speed.

The expulsion KE of massive particles is variable.

So be careful what is meant by the energy generated.

Edited by studiot
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