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Physical Evidence for the Division of Heavy Nuclei under Neutron Bombardment


FROM chemical evidence, Hahn and Strassmann1 conclude that radioactive barium nuclei (atomic number Z = 56) are produced when uranium (Z = 92) is bombarded by neutrons. It has been pointed out2 that this might be explained as a result of a ‘fission’ of the uranium nucleus, similar to the division of a droplet into two. The energy liberated in such processes was estimated to be about 200 Mev., both from mass defect considerations and from the repulsion of the two nuclei resulting from the ‘fission’ process.


  1. Hahn, O., and Strassmann, F., Naturwiss., 27, 11 (1939).

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  2. Meitner, L., and Frisch, O. R., NATURE [143, 239 (1939).

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  3. See Meitner, L., Strassmann, F., and Hahn, O., Z. Phys., 109, 538 (1938).

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FRISCH, O. Physical Evidence for the Division of Heavy Nuclei under Neutron Bombardment. Nature 143, 276 (1939).

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