Cross section measurements for (n,3n) reactions induced by 14.8 Mev neutrons

The cross sections for 209Bi(n,3n)207Bi, 191Ir(n,3n)189Ir, 151Eu(n,3n)149Eu and 185Re(n,3n)183Re reactions were measured by the activation method. The experimental results were 12.1±1.1, 64.6±6.5, 2.7±0.4 and 66.0±5.6 mb at the neutron energy of 14.8±0.2 MeV, respectively. The neutron flux was determined by the cross section of the 27Al(n,α)24Na reaction. The neutron energy in these measurements was determined by the method of cross section ratios for 90Zr(n,2n)89m+gZr and 93Nb(n,2n)92mNb reactions.