Cross sections and angular distributions for the 10B(e, e'n)9B reaction in the giant resonance region

The cross sections and angular correlations for neutron emission to various states in the residual nucleus, following the 10B(e, e'n) reaction, have been measured over the excitation energy range 18-33 MeV at the effective momentum transfer of 0.49 fm-1. In the giant resonance, neutron emission leads predominant population of two higher excited states: (6.97 MeV 7/2- (n5), 11.70 MeV 7/2- + 12.06 MeV 3/2- (n6,7)). This is the first observation for neutron population of these states. The angular distributions for each transition were fitted with Legendre polynomials. The angular distributions for n0 indicate an interference of a transition with the opposite parity to E1. The angular distributions for n5 and n6,7 have a peak at about 50deg ; they are quite different patterns from for n0. It might reflect lower E1 amplitude comparing to other multipole ones. It was confirmed that neutron emission from the giant resonance in 10B leaves the residual nucleus 9B not at the ground state but mainly at 6.97 MeV 7/2- and 11.70 MeV 7/2- +12.06 MeV 3/2- states as predicted by shell model calculations with intermediate coupling. (author)