Abstract

Following with the discovery of the electron by J. J. Thomson at the end of the nineteenth century a steady elucidation of the structure of the atom occurred over the next 40 years culminating in the discovery of nuclear fission in 1938–1939. The significant steps after the electron discovery were: discovery of the nuclear atom by Rutherford (Philos Mag 6th Ser 21:669–688, 1911 ), the transformation of elements by Rutherford (Philos Mag 37:578–587, 1919 ), discovery of artificial radioactivity by Joliot-Curie and Joliot-Curie (Comptes Rendus Acad Sci Paris 198:254–256, 1934 ), and the discovery of the neutron by Chadwick (Nature 129:312, 1932a , Proc R Soc Ser A 136:692–708, 1932b ; Proc R Soc Lond Ser A 136:744–748, 1932c ). The neutron furnished scientists with a particle able to penetrate atomic nuclei without expenditure of large amounts of energy. From 1934 until 1938–1939 investigations of the reaction between a neutron and uranium were carried out by E. Fermi in Rome, O. Hahn, L. Meitner and F. Strassmann in Berlin and I. Curie and P. Savitch in Paris. Results were interpreted as the formation of transuranic elements. After sorting out complex radio-chemistry and radio-physics O. Hahn and F. Strassmann came to the conclusion, beyond their belief, that the uranium nucleus split into smaller fragments, that is nuclear fission. This was soon followed in 1939 by its theoretical interpretation by L. Mietner and O. Frisch