Free The First War of Physics by Jim Baggott Page A

same day that McMillan and Abelson submitted their paper to Physical Review , Szilard received a manuscript from Princeton theoretical physicist Louis Turner on precisely the same subject.
    In January 1940 Turner had surveyed the literature on uranium fission and published a review in the journal Reviews of Modern Physics. This work had set him thinking. While all the attention had so far been diverted towards U-235, Turner now nagged away at the idea of producing atomic energy from the stable, and much more abundant, isotope U-238. The resonant capture of neutrons by U-238 was considered something of a nuisance, to be avoided in a reactor through the use of a suitable moderator. Now Turner followed much the same logic as Weizsäcker, McMillan and Abelson. Neutron capture by U-238 would create an unstable U-239 isotope, which would decay to form element 93. But Turner did not stop there. He had figured from theoretical principles that element 93 would be relatively unstable and would decay quite quickly, creating element 94.
    Element 94 opened up an altogether different kind of prospect. It would consist of 94 protons and 145 neutrons, making a total of 239. In this sense it paralleled the pattern in U-235, with 92 protons and 143 neutrons. Some simple calculations suggested that this new element would be even more fissionable than U-235. It would be produced from the abundant isotope U-238 and, because it was a new element with its own distinct chemical properties, it could be chemically separated from its uranium parent. Turner anticipated that element 94 could represent a new source of fissionable material for nuclear chain reactions.
    Turner had drafted a paper for submission to Physical Review and wanted Szilard’s opinion on whether or not it was safe to publish. ‘It seems as if it was wild enough speculation so that it could do no possible harm, but that is for someone else to say’, he told Szilard.
    Speculation it might have been, but Szilard was a master of this game. He was stunned by the implications. ‘With this remark of Turner,’ he later said, ‘a whole landscape of the future of atomic energy rose before our eyes.’ Szilard suspected that achieving self-sustaining chain reactions – and bombs – might be a lot easier with element 94 than with uranium itself.
    He recommended that Turner delay publication of his paper ‘indefinitely’.
    Undoubtedly a Fascist
    Despite these revelations, the Advisory Committee on Uranium still moved at a snail’s pace. Briggs, it seemed, was an innately cautious man. He could move at only one speed – full ahead slow.
    Things were about to change, however. Vannevar Bush had vacated his vice presidency of the Massachusetts Institute of Technology (MIT) toaccept the presidency of Washington’s Carnegie Institution in the summer of 1939. Bush had trained as an electrical engineer and had gone on to become a highly pragmatic scientific administrator. During the First World War he had worked on the development of a magnetic device capable of detecting submarines. The device worked well enough, but was never put into operation. This experience had taught him all he needed to know about the importance of proper liaison between military and civilian research in the development of weapons in a time of war.
    From his position as president of the Carnegie Institution, Bush lobbied for the establishment of a national organisation for just this kind of liaison. On 12 June 1940 he presented his arguments to Roosevelt, summarised in four short paragraphs in the middle of a sheet of paper. The groundwork had been done for him by Harry Hopkins, a Roosevelt aide, and the National Defense Research Council (NDRC) came into being. Its purpose was to direct all scientific research for military purposes.
    One of its first actions was to take over the Advisory Committee on Uranium. The need for censorship was immediately agreed – all research papers on uranium fission would henceforth be