Artificial radioactivity produced by neutron bombardment

Abstract This paper aims at giving a fuller account of experiments made in the Physical Laboratory of the University of Rome, on new radio-elements produced by neutron bombardment. Preliminary results have already been announced in short communications. Curie and Joliot first discovered that the product atom of an artificial disintegration need not always correspond to a stable isotope, but could also disintegrate with a relatively long mean life with emission of light particles. As bombarding particles they used α-particles from polonium, and found that the light particle emitted was generally a positron. Similar results were obtained on several elements by other experimenters using α-particles, and artificially accelerated protons and deutons.