Neutron science experiments

High Intensity Proton Accelerator Project-Neutron Experimental Facility is a research facility with a nuclear spallation type pulsed neutron source and meson source using 333 μA large proton current (1MW of accelerating proton power) from 3 GeV synchrotron. It is the most intense pulsed neutron source in the world. New development of science by this facility is summarized. The history of pulsed neutron, outline of neutron experimental facility, the next generation neutron experimental device and spectroscope, various kinds of neutron scattering and the science we are heading for by 1MW pulsed neutron experimental facility are described. New fields of science contain properties of oxide high temperature superconductor, structure phase transition, transient phenomena, structure of exited state, dynamics of amorphous, mesoscopic structure and dynamics of polymer, structure of protein, parametric studies, trace sample and nondestructive examination. (S.Y.)