- #1
Evanish
- 120
- 10
I was wondering if alpha particles created by radioactive decay ever have enough energy to fuse with something else (e.g. hydrogen or another alpha particle).
mfb said:They could fuse with a deuteron to Li-6, with C-12 to O-16, and there are many more options, the energy of most decays is sufficient to lead to fusion. All those processes are rare, however, most of the time the particle will lose its energy from interactions with electrons.
That's really interesting. If you striped away the electrons could you use alpha particle producers with a short half lives to make a fusion reactor? Maybe having the alpha particles shoot into some kind of ionized gas.mfb said:They could fuse with a deuteron to Li-6, with C-12 to O-16, and there are many more options, the energy of most decays is sufficient to lead to fusion. All those processes are rare, however, most of the time the particle will lose its energy from interactions with electrons.
Evanish said:That's really interesting. If you striped away the electrons could you use alpha particle producers with a short half lives to make a fusion reactor? Maybe having the alpha particles shoot into some kind of ionized gas.
Interesting. Thanks for the reply Drakkith. How do you find out the cross section of various possible events, and how exactly is it used to determine probability?Drakkith said:No, the cross sections of the reactions are far too small. The vast majority of the time the alpha particle would simply scatter off of the nucleus and not fuse.
Thanks for the info mfb. Is the cross-section always at most the size of the nuclei?mfb said:Finding precise numbers can be difficult, but here a rough order of magnitude is sufficient: the fusion cross-section is at most of the order of the size of the nuclei (probably much smaller), while relevant scattering (and therefore energy loss) is orders of magnitude more frequent.
Evanish said:Thanks for the info mfb. Is the cross-section always at most the size of the nuclei?
For fusion with alpha nuclei, I would be surprised to see a value larger than that.Evanish said:Thanks for the info mfb. Is the cross-section always at most the size of the nuclei?
Astronuc said:These sources are sealed, and besides the radiation and radiotoxicity of the radiaonuclides, Be is very toxic in the human body.
e.bar.goum said:5Li has a half-life of about half a zeptosecond, which is on the same order as the timescale of a nuclear collision
Vanadium 50 said:Not surprising, since it's unbound. There are no A=5 nuclei.
This is really interesting. Thank you. Could spallation from alpha particle produce neutrons cheaply and in enough numbers to transmute useful amounts of uranium 238 and thorium 232 into fissile isotopes which can then be used as nuclear fuel?Astronuc said:In the MeV range, scattering is largely potential scattering.
Basically, to measure cross-sections, one would take an ion bean, of alpha particles in this case, and impose the beam on a target material and measure the outcomes. One would do an energy sweep and generate cross-sections derived from scatter and whatever interactions evolved.
In the case of alpha particles, alpha-emitters like Ra, Po, Pu, Am have been mixed with Be to make (α, n) sources. AmBe neutron sources are used for startup sources for reactors, otherwise, spontaneous fission sources, e.g., 252Cf are used.
These sources are sealed, and besides the radiation and radiotoxicity of the radiaonuclides, Be is very toxic in the human body.
More later on fusion reactions.
e.bar.goum said:Absolutely true. Of all the things I handle in the lab, it's not the hot (quite radioactive) sources that give me the pause, it's anything to do with handling beryllium. New gloves, separate tools, respirator, the works. Beryllium gives you Berylliosis, which is quite similar to mesothelioma. This is quite unfortunate, because not only is beryllium quite handy for making a nice neutron source (and means that undergraduates can do neutron absorption measurements), it's a really interesting nucleus for those of us interested in the nuclear physics of light nuclei. It's also rather useful if you want to make beams of light exotic nuclei (6He, 8Li). So I end up coming across it more than I would like.
On the topic of the OP, 5Li has a half-life of about half a zeptosecond, which is on the same order as the timescale of a nuclear collision. I'm now wondering what measurement you would make that would distinguish straight-up rutherford scattering from α+p → 5Li -> α+p. γ-α or γ-p coincident measurements, and/or angular distributions, I suppose. I suspect that you would have your work cut out for you.
Evanish said:Thanks for the info. I was wondering is this possible?
α+H-2 -> Li-6
Thanks for the info. I don't know much of the theories involved so I'm not to clear on what is or isn't possible.e.bar.goum said:Sure. It's possible. Why wouldn't it be?
That's actually the major reaction that goes towards producing 6Li in the big bang. (Not that 6Li is produced in any serious abundance, but that's the reaction that produces it).
In general, a reaction is "possible" if it doesn't break any conservation rules and the nucleus exists (i.e. you don't fall off the side of either of the driplines). But that doesn't mean that the reaction is likely. Determining the likelihood of a reaction taking place (aka the reaction cross section) is a far more complicated business.Evanish said:Thanks for the info. I don't know much of the theories involved so I'm not to clear on what is or isn't possible.
I see. Good to know. Thank you.e.bar.goum said:In general, a reaction is "possible" if it doesn't break any conservation rules and the nucleus exists (i.e. you don't fall off the side of either of the driplines). But that doesn't mean that the reaction is likely. Determining the likelihood of a reaction taking place (aka the reaction cross section) is a far more complicated business.
I've been doing some more reading and I discovered that the thing with Beryllium isn't spallation.Evanish said:This is really interesting. Thank you. Could spallation from alpha particle produce neutrons cheaply and in enough numbers to transmute useful amounts of uranium 238 and thorium 232 into fissile isotopes which can then be used as nuclear fuel?
Yes, an Alpha Particle can fuse with a Hydrogen Atom under certain conditions.
An Alpha Particle is a type of nuclear particle made up of two protons and two neutrons, with a positive charge.
An Alpha Particle can fuse with a Hydrogen Atom through a process called nuclear fusion, where the nuclei of two atoms combine to form a larger nucleus.
An Alpha Particle can fuse with a Hydrogen Atom in extreme temperatures and pressures, similar to those found in the core of a star or during a nuclear explosion.
When an Alpha Particle fuses with a Hydrogen Atom, it forms a new element called Helium. This process also releases a large amount of energy in the form of radiation.