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Enrico Fermi: Atomic Energy, 9147

From Theoretical to Experimental

Following the 1932 discovery of the neutron and then the 1934 discovery of artificial radioactivity, Fermi resolved to experiment in producing artificial radioactivity by substituting neutron bombardment for the alpha particles method the French scientists had used. This signified a change in his academic priority from theoretical to experimental science.

He devised a procedure to produce neutrons from the combination of radon and beryllium, built a Geiger counter to measure the radioactivity produced, and began bombarding elements proceeding systematically through the Periodic Table. The first success in detecting radioactivity came with fluorine (atomic number=9) and the most noteworthy with uranium (atomic number=92). The disintegration of uranium produced a fleeting, unstable element of atomic number 93 never before known to exist. Immediate worldwide publicity about this "new element" followed the discovery. Fermi considered this publicity both premature and inappropriate. He considered claims that the scientific success was due to the Fascist environment equally unjustified. The full impact of the discovery of uranium disintegration would follow some years later.