Low-energy measurement of the Be-7(p,gamma) B-8 cross-section

摘要

We have measured the cross section of the 7Be(p,gamma)8B reaction for E_cm =185.8 keV, 134.7 keV and 111.7 keV using a radioactive 7Be target (132 mCi).Single and coincidence spectra of beta^+ and alpha particles from 8B and 8Be^*decay, respectively, were measured using a large acceptance spectrometer. Thezero energy S factor inferred from these data is 18.5 +/- 2.4 eV b and aweighted mean value of 18.8 +/- 1.7 eV b (theoretical uncertainty included) isdeduced when combining this value with our previous results at higher energies. Comment: Accepted for publication in Phys. Rev. Lett