Cross sections for the ${}_{}{}^7{}_{}{}^{}\mathrm{Be}(p,\gamma ){}_{}{}^8{}_{}{}^{}\mathrm{B}$ reaction have been measured at 20 proton energies ranging from 0.953 to 3.281 MeV. Measurements were made relative to the cross section for the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}\mathrm{}(d,p)\mathrm{}{}_{}{}^8{}_{}{}^{}\mathrm{Li}$ reaction at the 0.770-MeV resonance peak. The results were analyzed in two ways to obtain values for $S\left(0\right)\mathrm{}$, the zero-energy cross-section factor. The first type of analysis, based on the assumption that the observed cross section was composed of a nonresonant part and resonant contributions from the first two excited states of ${}_{}{}^8{}_{}{}^{}\mathrm{B}$, gave an $S\left(0\right)\mathrm{}$ of 0.0263 ± 0.0027 keVb. The second type of analysis assumed an additional resonance contribution from a higher-lying state and led to an $S\left(0\right)\mathrm{}$ of 0.0226 ± 0.0043 keVb. The result obtained from the second analysis represents our best estimate for the value of $S\left(0\right)\mathrm{}$ obtainable from the present measurements.

• Received 13 July 1970

DOI:https://doi.org/10.1103/PhysRevC.2.1657