We have measured the cross section of the ^ { 7 } Be ( p , \gamma ) ^ { 8 } B reaction for E _ { cm } = 185.8 keV , 134.7 keV and 111.7 keV using a radioactive ^ { 7 } Be target ( 132 mCi ) .
Single and coincidence spectra of \beta ^ { + } and \alpha particles from ^ { 8 } B and ^ { 8 } Be ^ { * } decay , respectively , were measured using a large acceptance spectrometer .
The zero energy S factor inferred from these data is 18.5 \pm 2.4 eV b and a weighted mean value of 18.8 \pm 1.7 eV b ( theoretical uncertainty included ) is deduced when combining this value with our previous results at higher energies .