We have measured the Coulomb dissociation of ${}^8\mathrm{B}$ into ${}^7\mathrm{Be}$ and a proton at 254 MeV/nucleon using a large-acceptance focusing spectrometer. The astrophysical $S_{17}$-factor for the ${}^7\mathrm{Be}(p,\gamma {)}^8\mathrm{B}$ reaction at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=0.25\mathrm{}–2.78\mathrm{MeV}$ is deduced yielding $S_{17}\left(0\right)=20.6\mathrm{}\pm 1.2$ (expt) $\pm 1.0\left(\mathrm{theor}\right)\mathrm{eV}\mathrm{b}$. This result agrees with the presently adopted zero-energy $S_{17}$-factor obtained in direct-reaction measurements and with the results of other Coulomb-dissociation studies performed at 46.5 and 51.2 MeV/nucleon.

• Received 8 April 1999

DOI:https://doi.org/10.1103/PhysRevLett.83.2910