Boron concentrations were determined for six carbonaceous chondritic meteorites using the reaction 11B(d,p)12B. The results imply a solar system B/H ratio of (2 ± 1) x 10-9. Although this ratio is much lower than that determined from previous meteoritic measurements, it remains significantly higher than the B/H ratios determined from the solar photosphere and other astrophysical environments.
Light element abundance ratios obtained from both meteoritic and photospheric data are compared with calculated values. It is concluded that two contributions are probably necessary to account for the observed ratios. Lithium, beryllium and boron nuclei produced according to the standard galactic cosmic ray model are expected to contribute significantly to the observed abundances. However, a component arising from low-energy spallation of CNO nuclei also appears necessary. Several possibilities are considered for the origin of these low-energy particles. However, the data and calculations are too uncertain to permit any firm conclusions.
