Homepage Forums Aneutronic Fusion Is Deuterium + Boron 10 aneutronic?

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  • #1071
    AvatarMTd2
    Member

    If not, what is the result?

    #9555
    AvatarIvy Matt
    Participant

    Yes and no. The primary reaction produces three alpha particles with a total of 17.5 MeV of energy, twice as much energy as is produced in the p+B11 reaction. However, deuterium fuses easily with itself (relatively speaking), producing neutrons or tritium in two equally possible reactions. Nevertheless, Wikipedia lists the D+He3 reaction as aneutronic, so by Wikipedia’s standards D+B10 should also count as aneutronic. Of course, even p+B11 produces a small amount of neutrons in side reactions.

    Also, if I understand correctly, the D+B10 reaction may occasionally produce C11 and a neutron.

    #9557
    AvatarMTd2
    Member

    What is the source of this information:

    “The primary reaction produces three alpha particles”. This is the same result of boron – 11, which was my question, but I couldn’t find the source.

    Also, the pinch of boron, according to Eric’s theory, is 10 times denser than lead. So, Boron-10 could work as a shield for neutrons.

    #9574
    AvatarIvy Matt
    Participant

    To be honest, my sources are kind of old:

    http://rspa.royalsocietypublishing.org/content/154/881/246.full.pdf

    http://rspa.royalsocietypublishing.org/content/154/881/279.full.pdf

    But I’m not aware of any newer work on the D+B10 reaction. I get the impression that many nuclear reactions haven’t been studied intensively since the 1950s, or even the 1930s, in some cases, but I could be wrong about that. As for the boron-10 shielding the neutrons in a DPF plasmoid, that’s an interesting idea, and, I presume, one that lies in the realm of the theoretical for now. Perhaps it could be studied after we find out how well the p+B11 reaction works in the FF-1 device.

    #9588
    AvatarMTd2
    Member

    Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

    #9589
    AvatarArvid
    Participant

    MTd2 wrote: Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

    This is a little 30-page chapter from a larger book that discusses a number of reactions relevant to controlled fusion and fusion in stars. (Warning: PDF.) Unfortunately, nothing about D + B 10. Interestingly, it shows p + B 11 with a huge, but very sharp resonance at 146 kEV, before its main peak over 500. Could some machine be designed to take advantage of that?

    #9594
    Avatarjamesr
    Member

    Arvid wrote:

    Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

    This is a little 30-page chapter from a larger book that discusses a number of reactions relevant to controlled fusion and fusion in stars. (Warning: PDF.) Unfortunately, nothing about D + B 10. Interestingly, it shows p + B 11 with a huge, but very sharp resonance at 146 kEV, before its main peak over 500. Could some machine be designed to take advantage of that?

    The full book is “Tokamaks” by John Wesson

    Although the resonance is important, the ions will be close to thermal equilibrium as so have a Maxwellian velocity distribution. If you refer to fig 1.5 on page 18 of the pdf, rather than fig 1.3 it shows the Maxwellian averaged fusion cross section. The averaged fusion cross section is slightly higher at temperatures below 100keV than it would otherwise be if you didn’t take the resonance into account. But to get to appreciable reaction rates you still need to be over 100keV.

    You could try a to create a non-Maxwellian system eg a beam of protons at exactly that energy. But the energy you need to create a beam will always be many orders of magnitude more than the benefit.

    #12220
    AvatarBSFusion
    Member

    jamesr wrote:

    Do you know a book with tables about cross sections for different elements, like proton or deuterium + element? It might be that D+B10 cross section is much higher than D+D at its peak value.

    This is a little 30-page chapter from a larger book that discusses a number of reactions relevant to controlled fusion and fusion in stars. (Warning: PDF.) Unfortunately, nothing about D + B 10. Interestingly, it shows p + B 11 with a huge, but very sharp resonance at 146 kEV, before its main peak over 500. Could some machine be designed to take advantage of that?

    The full book is “Tokamaks” by John Wesson

    Although the resonance is important, the ions will be close to thermal equilibrium as so have a Maxwellian velocity distribution. If you refer to fig 1.5 on page 18 of the pdf, rather than fig 1.3 it shows the Maxwellian averaged fusion cross section. The averaged fusion cross section is slightly higher at temperatures below 100keV than it would otherwise be if you didn’t take the resonance into account. But to get to appreciable reaction rates you still need to be over 100keV.

    You could try a to create a non-Maxwellian system eg a beam of protons at exactly that energy. But the energy you need to create a beam will always be many orders of magnitude more than the benefit.

    I think you have the wrong source for that pdf, it has been copied verbatim from Chapter #1 of “The Physics of Inertial Fusion” by Stepfano Atzeni and Jurgen Meyer-ter-vehn (2009).

    #12224
    Avatarjamesr
    Member

    Thanks for that – I think I realised it was wrong a while ago but never got round to correcting it. They are both printed my the same publisher and use the same layout which is what confused me I guess. Both are good books although expensive so you need a well stocked library have them available.

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