Current situations and perspective of fission research using neutrons

More than fifty years have passed after the discovery of fission phenomena, and many experimental and theoretical studies have been done. The usage of huge released energy in fission has been progressed actually. However, the fission mechanism has not been resolved yet by now. Nuclear fission is caused by injection of neutrons, charged particles including heavy ions or gamma ray to heavy nucleus, and by itself. Nuclear fission gives us many information such as fission cross section, fragment mass and kinetic energy distributions, fragment charge distribution, number of prompt neutrons, fission neutron energy spectra, etc. In this paper, current situation of neutron-induced fission research is introduced by focusing topical experiments, and personal perspective is described. (author)