Status of the neutron nuclear physics studies in the world

The nuclear physics studies with fast neutrons will continue to be one of the important subjects for many basic and application fields in the next century. Today, the most intensive use of fast neutrons produced by spallation reactions is carried out at Los Alamos Neutron Science Center (LANSCE) where neutrons produced by 800-MeV protons on a tungsten target are used at several beam lines simultaneously. Other form of utilization of fast-neutrons above 20 MeV is realized by using the 7Li(p,n)7Be reaction as the quasi mono-energetic neutron source, or by the T(d,n)3He or other similar reactions. This report describes the status of nuclear physics studies using fast neutrons above 20 MeV with these neutron sources, placing an emphasis on the Los Alamos and JAERI activities, together with the scope of studies at the Center for Neutron Science project of JAERI. (author)