Measurement of eV-region pulse shapes of neutrons from the KENS thermal neutron source by a neutron resonance absorption method

The eV-region pulse data of neutrons emitted from a moderator at a pulsed neutron source are important for scattering experiments using eV region neutrons. Therefore, we measured the pulse data of neutrons from the H2O thermal moderator at KENS, using a neutron resonance absorption spectrometer (N-RAS) because it can give the pulse information due to the fact that it includes pulse shape information in a form of convolution with the resonance spectrum. We also performed a simulation calculation for the pulse shapes. It was found that the pulse widths obtained experimentally were proportional to E-0.48, which result is almost equal to those of the simulation, and there existed little difference in widths compared with those evaluated by using the slowing down theorem in an infinite medium having mass number 1. (author)