Measurements of keV-Neutron Capture Cross Sections and Capture Gamma-Ray Spectra of 161,162,163Dy.

Abstract

The neutron capture cross sections and capture γ-ray spectra of 161 162 163Dy were measured in the neutron energy region of 10 to 90 keV and at 550 keV. A neutron time-of-flight method was adopted with a ns-pulsed neutron source by the 7Li(p, n)7Be reaction and with a large anti-Compton NaI(Tl) γ-ray spectrometer. A pulse-height weighting technique was applied to observed capture γ-ray pulse-height spectra to derive capture yields. The capture cross sections were obtained with the error of about 5% by using the standard capture cross sections of 197Au. The present results were compared with previous measurements and the evaluated values of ENDF/B-VI. Capture γ-ray spectra were obtained by unfolding observed capture γ-ray pulse-height spectra. An anomalous bump was observed around 2.5 MeV in the γ-ray spectra of each isotope, and the energy position of the bump was consistent with the systematics obtained in our previous work.