Neutron yields from the bombardment of a Au target by 164- and 142-MeV O ions have been measured at angular intervals of 15 deg from 0 to 165 deg. Neutrons with energy from 0 to 12 MeV were detected by means of nuclear emulsions with use of the internal-radiator method. The O-deg-yield measurements were extended to a neutron energy of 2 5 MeV by using a polyethylene radiator together with nuclear emulsions for neutron detection. The yields at 164 and 142 MeV are subtracted in order to obtain differential cross sections averaged over this energy interval, which are then transformed to the center-of-mass system. It is known that this reaction leads to fission in most cases, so that the problem of neutron-fission competition arises. The anisotropy coeffi2 client, a, defined by the expression W (0) = 1 + a cos 6, is about 1 for 2-MeV neutrons and decreases rapidly with neutron energy. The distribution of neutrons is essentially isotropic above 6 MeV. This behavior disagrees with calculations of the angular distribution of neutrons from fission fragments, which are based on measured fragment angular distributions.
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