B8proton halo via reaction and breakup cross section measurements

The reaction cross section for ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ and the breakup cross section for ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ on silicon have been measured for incident energies between 10 and 40 MeV/nucleon with a stack of silicon detectors. Secondary ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ beams were obtained by use of the LISE spectrometer at GANIL. The stack of silicon detectors had the multiple purpose of slowing down the incident secondary beams, identifying the reaction products, and measuring their energy. The separate contributions of diffraction dissociation and absorption to the breakup have been determined. The parallel momentum distribution of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ resulting from the breakup of ${}_{}{}^8{}_{}{}^{}\mathrm{B}$ has also been determined. The data are compared to theoretical calculations. © 1996 The American Physical Society.