Accurate determination of cross-sections for 238U (n, 2n) 237U induced by neutrons around 14 MeV

The cross-sections of 238U (n, 2n) 237U induced by neutrons with energies around 14 MeV were determined by measuring the emission rate of 208.00 keV γ-rays from 237U decay with an accurately calibrated HPGe γ-ray spectrometer at CIAE. In order to correct for the self-attenuation of 208.0 keV γ-ray in U sample, a 177Lu-spiking method was introduced. As a result, a total relative standard uncertainty of 2.5% was achieved for the measured cross-section values.