Study of neutron fluence rate fluctuation factor in nuclear reaction cross section measurement

The correction formula for the neutron fluence rate fluctuation on the measured radioactive of the neutron irradiated sample was obtained based on the regulation of growing and decay of artificial radioactive nuclide. This was done based on the fluence of the 14 MeV monoenergetic neutron generated by T(d,n)He-4 reaction. Combining with the actual measured counts and spectra of the accompanying alpha-particles, for the different irradiating time, the different half-life, neutron fluence rate fluctuation factor was calculated and discussed. The experimental results show that in the cross section measurement of neutron-induced reactions, the irradiation time of the samples should be less than or close to the half-life period of the daughter nucleus of the measured reaction such that the corrected values of the fluctuation factors are close to one.