Low energy measurements of the B10(p,α)Be7 reaction

Background: The $^{11}\mathrm{B}{(p,2\ensuremath{\alpha})}^{4}\mathrm{He}$ reaction is being discussed as a prime candidate for advanced aneutronic fusion fuel systems. Particular interest in this reaction has recently emerged for laser driven plasma systems for energy generation and jet-propulsion systems. The lack of long-lived radioactive reaction products has been suggested as the main advantage of proton-boron fusion fuel. However, 19% of natural boron is $^{10}\mathrm{B}$, with the $^{10}\mathrm{B}(p,\ensuremath{\alpha})^{7}\mathrm{Be}$ fusion reaction producing long-lived $^{7}\mathrm{Be}$ as a side product.Purpose: A detailed measurement of the $^{10}\mathrm{B}(p,\ensuremath{\alpha})^{7}\mathrm{Be}$ reaction over the critical energy range of hot fusion plasma environments will help to determine the amount of $^{7}\mathrm{Be}$ radioactivity being produced. This information can be used in turn to monitor the actual fusion temperature by offline measurement of the extracted $^{7}\mathrm{Be}$ activity. The goal of the here presented experiment is to expand on the results of earlier experiments, covering a wider energy range of interest for aneutronic plasma fusion applications, including also both $^{10}\mathrm{B}(p,{\ensuremath{\alpha}}_{0})^{7}\mathrm{Be}$ and the $^{10}\mathrm{B}(p,{\ensuremath{\alpha}}_{1})^{7}\mathrm{Be}$ reaction channels.Method: The reaction cross section was measured over a wide energy range from ${E}_{p}=400$ to 1000 keV using particle detection and from ${E}_{p}=80$ to 1440 keV using $\ensuremath{\gamma}$-ray spectroscopic techniques. Reaction $\ensuremath{\alpha}$ particles were measured at different angles to obtain angular distribution information. The results are discussed in terms of an $R$-matrix analysis.Results: The cross section data cover a wider energy range than previously investigated and bridge a gap in the previously available data sets. The cross sections show good agreement with previous results in the low energy region and show that the $^{10}\mathrm{B}(p,{\ensuremath{\alpha}}_{0})^{7}\mathrm{Be}$ channel is considerably larger than that of the $^{10}\mathrm{B}(p,{\ensuremath{\alpha}}_{1})^{7}\mathrm{Be}$ channel up to ${E}_{p}\ensuremath{\approx}1\phantom{\rule{4pt}{0ex}}\mathrm{MeV}$.Conclusions: The new reaction data provides important new information about the reaction cross section over the entire energy range of plasma fusion facilities. This data, when coupled with previous measurement of the competing $^{10}\mathrm{B}(p,\ensuremath{\gamma})^{11}\mathrm{C}$ reaction, will provide the opportunity for an extensive $R$-matrix analysis of the rather complex level structure in the $^{11}\mathrm{C}$ compound nucleus system.