Is this how nuclear fission occurs with neutron bombardment?

In summary, when neutrons are fired at atoms, they can behave as waves at higher speeds, resulting in scattering and potentially producing x-ray diffraction images. However, when slowed to the right "thermal energy" speed, they are more likely to be captured by a nucleus, such as U-235, causing it to become unstable and break apart into daughter nuclei, neutrons, and gamma radiation. This behavior is a result of quantum mechanics and does not fit a classical image of waves or particles. While there is always a probability for different interactions to occur, there is no situation where the capture of a neutron by a nucleus is impossible. Direct splitting of nuclei, on the other hand, only occurs at much higher energies.
  • #1
victorhugo
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When neutrons are fired at atoms, if at higher speeds they will behave as waves, wander through and scatter, (which can produce something similar to x-ray diffraction images), but if slowed to the right "thermal energy" speed, they will be captured by (say) U-235, making the U atom unstable, causing it to break up into 2 daughter nuclei + neutrons + gamma radiation

I'd appreciate further explanation and a correction of any of my statements that are wrong and/or incomplete :)
 
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  • #2
No. The wave behaviour appears at all speeds and is more usefully thought of as part of the statistical behaviour of the particle.
Neutrons may be captured by a nucleus at any speed - it is just that there is more opportunity to catch a slow neutron than a fast one ... much like it is easier to catch a slow ball than a fast one. It's a bit more complicated for nucleon capture by a nucleus ... you can get graphs of the neutron capture crosssection vs energy online.
 
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  • #3
Simon Bridge said:
No. The wave behaviour appears at all speeds and is more usefully thought of as part of the statistical behaviour of the particle.
Neutrons may be captured by a nucleus at any speed - it is just that there is more opportunity to catch a slow neutron than a fast one ... much like it is easier to catch a slow ball than a fast one. It's a bit more complicated for nucleon capture by a nucleus ... you can get graphs of the neutron capture crosssection vs energy online.
I see. So what conditions make it so that it can safely wander through the nucleus of an atom and diffract, than otherwise being captured?
Also, I've seen somewhere that particles are bombarded at nuclei, splitting them apart. Is this the same thing with U-235 capturing a neutron?
 
  • #4
victorhugo said:
I see. So what conditions make it so that it can safely wander through the nucleus of an atom and diffract, than otherwise being captured?
Quantum mechanics. There is no classical image that would fit (and waves and particles are classical images).
victorhugo said:
Also, I've seen somewhere that particles are bombarded at nuclei, splitting them apart. Is this the same thing with U-235 capturing a neutron?
No, the direct splitting happens at much higher energies.
 
  • #5
So what conditions make it so that it can safely wander through the nucleus of an atom and diffract, than otherwise being captured?
In all conditions there is a probability for different interactions to take place. I don't think there is a situation where the n+U capture crossection is zero.
 

1. What is nuclear fission and how does it occur with neutron bombardment?

Nuclear fission is a process in which the nucleus of an atom splits into smaller fragments, releasing a large amount of energy. This process can occur naturally or through artificial means, such as neutron bombardment. Neutron bombardment involves firing neutrons at the nucleus of an atom, causing it to become unstable and split apart.

2. What is the role of neutrons in nuclear fission?

Neutrons play a crucial role in nuclear fission as they are able to penetrate the nucleus of an atom and cause it to split apart. This process releases more neutrons, which can then go on to cause a chain reaction, releasing a large amount of energy.

3. Can nuclear fission occur without neutron bombardment?

Yes, nuclear fission can occur naturally through a process called radioactive decay, where the nucleus of an atom spontaneously splits into smaller fragments. However, this process is not as controllable or efficient as the fission that occurs with neutron bombardment.

4. What are the potential dangers of nuclear fission with neutron bombardment?

The main danger of nuclear fission with neutron bombardment is the release of large amounts of radiation and radioactive materials. This can have harmful effects on living organisms and the environment. Additionally, if the process is not properly controlled, it can lead to a nuclear meltdown, which can have catastrophic consequences.

5. How is nuclear fission with neutron bombardment used in practical applications?

Nuclear fission with neutron bombardment is used in nuclear power plants to generate electricity. The fission process produces a large amount of heat, which is then used to create steam and drive turbines that generate electricity. It is also used in nuclear weapons, where the release of energy from fission is harnessed for destructive purposes.

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