title: The discoveries of uranium 237 and symmetric fission - from the archival papers of Nishina and Kimura.
abstract: Shortly before the Second World War time, Nishina reported on a series of prominent nuclear physical and radiochemical studies in collaboration with Kimura. They artificially produced (231)Th, a member of the natural actinium series of nuclides, by bombarding thorium with fast neutrons. This resulted in the discovery of (237)U, a new isotope of uranium, by bombarding uranium with fast neutrons, and confirmed that (237)U disintegrates into element 93 with a mass number of 237. They also identified the isotopes of several middle-weighted elements produced by the symmetric fission of uranium. In this review article, the highlights of their work are briefly summarized along with some explanatory commentaries.
authors.affiliation: University of Tsukuba, Ibaraki, Japan. ikedanke@yahoo.co.jp
authors.forename: Nagao
authors.initials: N
authors.lastname: Ikeda
mesh_terms: D001109:Archives; D049673:History, 20th Century; D007554:Isotopes; D009680:Nuclear Fission; D013910:Thorium / Q000737:chemistry / Q000266:history; D014501:Uranium / Q000737:chemistry / Q000266:history*
chemical_list: D007554:Isotopes; D014501:Uranium; D013910:Thorium