Angular Distribution and Polarization of Neutrons from theBe9(p, n0)B9andB11(p, n0)C11Reactions

The angular distribution of neutrons from the ${\mathrm{Be}}^9(p, n_0){\mathrm{B}}^9$ reaction has been measured for the proton energies between 3.5 and 10.9 MeV and from the $B^{11}(p, n_0){\mathrm{C}}^{11}$ reaction at 7.1 and 8.2 MeV over the angular range of 0 to 150°. The polarization of the neutrons from the two reactions was measured for proton energies from 7 to 11 MeV and neutron emission angles between 0 and 80°. Both experiments employed the Livermore time-of-flight facility. Neither the angular distribution nor the angular dependence of the polarization of the ${\mathrm{Be}}^9(p, n_0){\mathrm{B}}^9$ neutrons changes appreciably with increasing proton energy, while for the $B^{11}(p, n_0){\mathrm{C}}^{11}$ reaction, both the angular distribution and polarization are quite energy-sensitive. These results are not in agreement with the twin-reaction hypothesis of Bloom et al.