Mechanism of the reaction 181Ta(p, n)181W at proton energies below 10 MeV

The spectra and angular distributions of neutrons from the reaction 181Ta(p, n)181W have been measured for proton energies from 5.76 to 9.83 MeV with a step approx.1 MeV. The neutron spectra were measured by the time-of-flight method in the EGP-10M charge-exchange accelerator for neutron-emission angles from 30 to 1500 with a 300 step. It is shown that the angular distributions of the neutrons of the high-energy part of the spectra have an anisotropic nature, starting at a proton energy E/sub p/ = 7.80 MeV. This behavior of the angular distributions indicates that in the hard part of the spectrum there is a contribution of direct processes. Methods of experimental separation of the contribution of nonequilibrium processes in the integrated spectra are discussed. The level density obtained, after taking into account the contribution of nonequilibrium processes, agrees satisfactorily with the predictions of the back-shifted Fermi gas model