EVIDENCE FOR A PROTON HALO IN B-8 - ENHANCED TOTAL REACTION CROSS-SECTIONS AT 20 TO 60 MEV NUCLEON/

Total reaction cross sections sigma(R) for B-8, C-12, and N-14 On Si-n at were measured from about 20 to 60 MeV/nucleon. The sigma(R) for C-1 2 and N-14 compared reasonably well with conventional strong absorptio n and microscopic calculations. Measured sigma(R) for B-8 were slightl y larger than those for the two heavier nuclei, and notably larger tha n the conventional calculations. The B-8 data were well reproduced by microscopic calculations using the same matter distribution used to ex plain the B-8 quadrupole moment data, and therefore provide new eviden ce for the existence of a proton halo in B-8.