  The neturon rich nucleus 13B was studied via the proton transfer reaction
4He(12Be,13B \gamma) at 50AMeV. The known 4.83-MeV excited state was strongly
populated and its spin and parity were assigned to 1/2+ by comparing the
angular differential cross section data with DWBA calculations. This low-lying
1/2+ state is interpreted as a proton intruder state and indicates a
deformation of the nucleus.

Nuclear Experiment