CNO fusion using particle accelerator?

  • #1
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Main Question or Discussion Point

The CNO cycle (see https://en.wikipedia.org/wiki/CNO_cycle) is a catalytic fusion reaction that produces energy in stars larger than the sun. It converts four protons into a helium-4 nucleus using a cycle of carbon, nitrogen and oxygen isotopes as catalysts and releases 26.7 MeV of energy mostly in the form of gamma rays.

Could one make this cycle work in the laboratory by bombarding a high-density target made of these isotopes with protons accelerated in a particle accelerator?

If a carbon nucleus has a radius of about ##2.7\times10^{-15}## m then one would require protons to be accelerated to about ##3.2## MeV in order to overcome the Coulomb repulsion. I guess this can easily be achieved. If the energy of the gamma rays was captured perhaps one could produce fusion energy by this method?
 

Answers and Replies

  • #2
phyzguy
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Many people have thought about trying to produce fusion with particle accelerators. Suppose I fire high-energy nuclei at a target (say I fire deuterium nuclei at a deuterium target). A very few of the nuclei will hit a target nucleus "head-on", overcome the Coulomb barrier, and fuse. The vast majority of the incoming nuclei, however, will lose their energy through Coulomb scattering off the nuclei and electrons in the target. The amount of fusion energy produced in this way is far less than the energy needed to accelerate the incoming nuclei. It just doesn't work.
 
  • #3
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Could one insert the target into the accelerator ring so that any beam particles that don't collide with target nuclei are collected and sent round the accelerator again until they do collide?
 
  • #4
phyzguy
Science Advisor
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They still collide, they just don't collide with a nucleus head on. They collide with a nucleus with a non-zero impact parameter and are deflected or they collide with electrons and lose energy.
 

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