FERMI, E., E. AMALDI, O. D'AGOSTINO, F. RASETTI, E. SEGRÉ. - THE FIRST ARTIFICIAL RADIOACTIVITY BY NEUTRON BOMBARDMENT.

Artificial Radioactivity produced by Neutron Bombardment. (Communicated by Lord Rutherford) + Artificial Radioactivity produced by Neutron Bombardment - II. (Communicated by Lord Rutherford). 2 Papers.

London, Harrison and Sons, 1934 a. 1935. Royal8vo. Bound in 2 contemp. full cloth. Gilt lettering to spine. A stamp on verso of titlepages. In: "Proceedings of the Royal Society", Series A, Vol. 146 and vol. 149. VI,942 pp. + VIII,600 pp. (Entire volumes offered). The joint papers: pp. 483-500 (1934) and pp. 522-558 (1935).

These seminal papers constitutes the description of the first realization of artificial radioactivity produced by neutron bombardment, and it is the first demonstration of neutron-induced radioactivity. These highlights and his many other results have left their imprint on the most diverse parts of physics. Fermi was awarded the Nobel prize in 1938 for these discoveries.

"Acting on this idea, (Fermi reasoned that neutrons should be more effective than alpha particles in producing radioactive elements because they are not repelled by the nuclear charge and thus have a much greater probability of entering the target nuclei) Fermi bombarded several elements of increasing atomic numbers with neutrons. He hoped to find an artificial radioactivity produced by the neutrons. His first success was with fluorine. The neutron source was a small ampul containing beryllium metal and radon gas. The detecting apparatus consisted of rather primitive Geiger-Müller counters. Immediately thereafter Fermi, with the help of Amaldi, D’Agostino, Rasetti, and Segrè, carried out a systematic investigation of the behavior of elements throughout the periodic table. In most cases they performed chemical analysis to identify the chemical element that was the carrier of the activity. In the first survey, out of sixty-three elements investigated, thirty-seven showed an easily detectable activity. The nuclear reactions of (n, a), (n, p), and (n, ?) were then identified, and all available elements, including uranium and thorium, were irradiated. In uranium and thorium the investigators found several forms of activity after bombardment but did not recognize fission. Fermi and his collaborators, having proved that no radioactive isotopes were formed between lead and uranium, put forward the natural hypothesis that the activity was due to transuranic elements. These studies, which were continued by Otto Hahn, Lise Meitner, Irène Joliot Curie, Frédéric Joliot, and Savitch, culminated in 1938 in the discovery of fission by Hahn and Fritz Strassmann."(DSB).

"The present papers are a summary of these letters (the letters from the team communicated almost weakly to "Ricerca Scientifica") for the English speaking readers. "When we (Fermi and Segre) went to Cambridge, we discussed with him (rutherford), in great detail, our work. The work which had been accomplished up to that date by our group is summarized in a paper which was presented by Lord Rutherford to the Royal Society (Paper No. 98). The manuscript of this paper had been prepared in Rome and delivered to him in Cambridge. he read it immediately with great attention, made several corrections to improve our English, and turned it over to the Royal Society. I asked him whether it would be possible to obtain a speedy publication and he immediately answered "What did you think I was President of the Royal Society for ?" (Collected Papers of Enrico Fermi, Vol. I, p. 641).

Volume 149 contains the importent joint paper on SUPERCONDUCTIVITY by the brothers FRITZ And H. LONDON "The Electromagnetic Equations of the Superconductor", pp. 71-88.

"In 1933 shortly before Heinz London joined his brother at Oxford, W. Meissner and R. Ochsenfeld made a startling discovery. It was well known that currents in superconductors flow in such a way as to shield points inside the material from changes in the external magnetic field. This indeed is an obvious property of any resistance less medium, fully discussed by Maxwell in 1873 long before the discovery of superconductivity. But a superconductor does more. Whereas a zero resistance medium only counteracts changes in the field, it actually tends to expel the field present in its interior before cooling.... The London quickly saw its implications and in 1935 published a joint paper on the electrodynamics of superconductors, in which they replaced (paper by Deaver and Fairbanks) by a new phenomenological equation connecting the current with the magnetic rather than the electric field... "(DSB).

Order-nr.: 47070