Isomeric yield ratio of Au-196m,Au- g in the Au-197(n, 2n) reaction with fast neutron based on the Be-9(p, n) reaction

摘要

The isomeric yield ratios (IR) of Au-196m,Au-g in the Au-197(n, 2n) reaction at the average neutron energies (< E-n >) of 14.4, 21.8 and 29.5MeV have been measured by using the off-line gamma-ray spectrometric technique. The neutron beams were obtained by using the Be-9(p, n) reaction with the proton energies of 25, 35 and 45MeV from the MC-50 cyclotron at KIRAMS. The IR values at different neutron energies were also calculated from the cross sections values based on TENDL-2017 library and are found to be in agreement around 10-18MeV but not at higher energy. The IR values of Au-196m,Au-g at the neutron energies of 21.8 and 29.5MeV have been measured for the first time. The present data along with the literature data at other energies in the Au-197(n, 2n) reaction are compared with the similar data in the Au-197(gamma, n) reaction to examine the role of entrance channel parameters and occurrence of non-compound or pre-equilibrium process at higher projectile energy.