NNDC lists only 15N+a->19F+hv (and then only in the 4-8MeV range, for the alpha). I guess the residual energy difference between 19F and 15N+a is too small to disrupt the nucleus by the strong force.KitemanSA wrote:What would an alpha + 15N do? That is the analogous reaction to the main neutron producing reaction of the pB11 cycle.
Some sci-fi questions
The Redstone used LOX/alcohol engines. Fuel was 75% ethanol, 25% water. Von Braun's team used it to mix drinks.D Tibbets wrote:I'm sure it is a pipe dream, but it would be cool to have a nuclear reacter that ran on methane (or perhaps booze- you could literally drink up your fuel :wink: ).
Dr. Nebel has gone on record as saying that EMC2's calculations indicate neutronicity of about 1e-8 for p-11B. A large part of that is the fact that alphas don't stick around long in the wiffleball because of their large gyroradii; an alpha supposedly makes about a thousand passes on average and leaves through one of the cusps.taniwha wrote:That would explain the comments I've seen about gamma power being about 0.1% and neutrons being 1e-3 to 1e-9 (for my shield calculations, I used 0.1% for both).
Ok, that makes sense. I didn't catch that from your prior discussion. Now it is clear. Thanks!chrismb wrote:See my earlier reply. These are the 'dwell' times that these reactants need to dwell for, in the Sun at the Sun's core temperature, to lead to this reaction. This is a reaction rate, not a half-life of the fusion products.KitemanSA wrote:These half-lives seem odd.
Just to make sure, the equation should read more like:
15N + 1H + 1.12e5 years → 12C + 4He +4.96 MeV
right?
For clarity it should fo something like this:KitemanSA wrote:Ok, that makes sense. I didn't catch that from your prior discussion. Now it is clear. Thanks!chrismb wrote:See my earlier reply. These are the 'dwell' times that these reactants need to dwell for, in the Sun at the Sun's core temperature, to lead to this reaction. This is a reaction rate, not a half-life of the fusion products.KitemanSA wrote:These half-lives seem odd.
Just to make sure, the equation should read more like:
15N + 1H + 1.12e5 years → 12C + 4He +4.96 MeV
right? :D
15N + 1H + (1.12e5 years @ xxx deg. K) → 12C + 4He +4.96 MeV
Assuming of course some kind of Maxwellian distribution.
Engineering is the art of making what you want from what you can get at a profit.
Yup. This is for our Sun, and is therefore for a thermal plasma (of some 500g/cc density, not that that affects the specific reaction time) at some 1 to 2keV.MSimon wrote: For clarity it should fo something like this:
15N + 1H + (1.12e5 years @ xxx deg. K) → 12C + 4He +4.96 MeV
Assuming of course some kind of Maxwellian distribution.