Measurement of Neutron Capture Cross Sections with Fe-Filtered Beam

Abstract

The neutron capture cross sections of 93Nb, 115In, 127I, 165Ho, 181Ta, 232Th and 238U were measured using the Fe-filtered beam. A 15-cm thick Fe filter was placed in the neutron beam produced by the KUR 46-MeV electron Linac and capture prays were detected by two C6F6 scintillation detectors located at an 11.7 m-flight path. The pulse-height weighting technique was used to determine the relative capture pray detection efficiency. The neutron flux was measured by the same detectors, whose detection efficiency for the 480-keV pray from the 10B(n, α1) reaction was calibrated by the saturated resonance capture in Ag at 5.2-eV. Self-shielding and multiple scattering corrections were applied to the data. The results of 24-keV capture cross sections are 340, 770, 780, 1,280, 880, 520 and 520 mb for 93Nb, 115In, 127I, 165Ho, 181Ta, 232Th and 238U, respectively. Total errors are 5 to 8%, with an estimated systematic error of 4%. The discrepancy between the present results and other data measured recently is within 10%.