Neutron capture cross-section measurement of 237Np below 10 keV by linac time-of-flight method

Experimental study on 'Neutron Capture Cross-Section Measurement of 237Np below 10 keV by Linac Time-of-Flight Method' has been carried out at the Research Reactor Institute, Kyoto University (KURRI). The neutron capture cross-section of 237Np has been measured in the energy region from 0.01 eV to 10 keV by using the neutron time-of-flight (TOF) method with a 46 MeV electron linear accelerator (linac). A pair of C6D6 scintillation detectors, which was placed at a distance of 12.0±0.02 m from the pulsed neutron source, was employed for the prompt capture gamma-ray measurement from the 237Np sample. The measured result has been normalized to the reference value of the 237Np(n, ηo)238Np reaction in ENDF/B-VI at 0.0253 eV. The existing experimental and the evaluated capture cross-sections in ENDF/B-VI and JENDL-3.2 have been compared with the present measurement. The data measured by Weston et al. and both of the evaluated data are in general agreement with the present measurement. However, the data by Hoffman et al. are obviously lower in the relevant energy region. We measured the capture cross section before using a lead slowing-down spectrometer at KURRI. The measured data are in good agreement with the present TOF data which are energy-broadened by the resolution function of the spectrometer. (author)