Cross Section for ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}\mathrm{}(p,2p)\mathrm{}$ ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ at 150 and 600 MeV: Implications for Cosmic-Ray Studies

The cross section for ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}\mathrm{}(p,2p)\mathrm{}$ ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ has been measured to be 19 ± 6 and 25 ± 8 mb at 150 and 600 MeV, respectively. These values show that the tertiary production of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ in cosmic rays is very important. However, it still appears likely that an actual isotope abundance measurement in cosmic rays will be necessary to utilize this nuclide as a cosmic-ray "clock."