LPPFusion’s research has from the start been aimed at using hydrogen and boron as the neutron-free fuel for a fusion generator. Other groups are also working towards using this ideal fuel. This month, there was some good news for this fuel’s prospects. Researchers at Duke University and the Triangle Universities Nuclear Laboratory in Durham, NC published results showing that the fuel, known scientifically as pB11, will burn somewhat faster than had previously been thought. This will make it easier for FF-1 and other devices to reach net energy using this fuel.
Since nuclear physics has not advanced to the point that nuclear reaction rates can be calculated theoretically, researchers use measurements obtained when nuclei collide in experiments using small particle accelerators. But these experiments have limitations as very low energy collisions are hard to distinguish from background radiation, among other problems.
The two Durham researchers, Drs. Sikora and Weller, found that measurements of the energy spectrum of the alpha particles (helium nuclei) produced by the reaction could be used to overcome these problems, arriving at a more accurate measurement of the cross section of the reaction (the probability that two nuclei will undergo the reaction) at all energies of collision. These cross sections were then used to calculate the reaction rate for the fuel at any temperature.
The net result was to increase the expected burn rate by 15% over calculations and measurements performed in 2012. This is actually better than it sounds, as many analyses of pB11 fusion, including those published by LPPFusion researchers, relied on still earlier results, which were nearly a factor of two lower than the new Durham numbers. Using the new numbers will reduce the plasma density needed to get net energy with pB11 by a similar amount, around a factor of two.