Slow neutrons in Palermo: a forgotten conference by Enrico Fermi

Abstract

On October 22, 1934, in a famous experiment, Enrico Fermi and his colleagues discovered that a significant increase in induced radioactivity can be obtained when neutrons are slowed down by means of hydrogen atoms. This discovery and its explanation earned him the 1938 Nobel Prize in Physics. One year later, on October 1935, Fermi held a public speech in Palermo, Italy, presenting his findings at the 24th congress of the Italian Society for the Progress of Sciences. The transcription of his speech, entitled "Recenti risultati della radioattività artificiale" (Recent Results in Artificial Radioactivity), was soon published in Italy. The published text is one of the very first articles in which Fermi describes the success of the Via Panisperna boys and how he came to discover that hydrogen atoms slowed the neutrons. Unfortunately, the content of the original Italian speech has never been republished since and was forgotten. Similarly, a translation published internally by the US Atomic Energy Commission is not publicly available and is probably lost. In this work, we include the transcription of the original article in Italian, and we also propose an English translation to make the text available worldwide to a broader public.