Production of Induced Radioactivity by High Velocity Protons

Nitrogen‐13: historical review and future perspectives

“…However, it has been applied in nitrogen fixation 8,9 and ventilation studies in animals 10 and humans. Historically, after the pioneering work by Cockcroft et al, 6 13 N was first produced as […”

Enrico Fermi’s Discovery of Neutron-Induced Artificial Radioactivity:The Influence of His Theory of Beta Decay

“…The conditions for the inverse case, the transformation of a proton into a neutron with the emission of a positron by increasing the relative number of protons in nuclei, had already been established in Joliot and Curie's experiments with alpha particles, and in subsequent ones by John D. Cockcroft (1897Cockcroft ( -1967 and his coworkers at the Cavendish Laboratory with protons. 38 Further, Ernest O. Lawrence and his coworkers at the University of California in Berkeley, and H. Richard Crane (1907Crane ( -2007 and Charles Lauritsen (1892-1968) at the California Institute of Technology in Pasadena, bombarded light nuclei with deuterons (and also protons), producing neutrons and radioactive nuclei that decayed with the emission of positrons. 39 In our view, therefore, this asymmetric experimental situation provided a strong motivation for Fermi, just a few days after he presented Wick's paper to the Accademia dei Lincei on March 4, 1934, to produce an intense Rn-Be neutron source and to construct the experimental apparatus he needed to bombard elements with Rn-Be neutrons, as we discussed earlier.…”

A Conversation with William A. Fowler – Part II

“…12 Cockcroft and his gang had also found radiation in carbon-12 plus protons. 13 Tuve and Hafstad in their first paper said [in effect], "It's all nonsense. All they're measuring is the background due to the deuterium contamination in their hydrogen beam."…”

“…It was mainly Oppie's influence that in the one paper they published on the subject they actually suggested that instead of C 12 (p, γ) making N 13 ,* they said -I know this was due to Oppie's insistence -that an alternative mechanism for the production of the N 13 was to hit the C 13 , the rare isotope of carbon, with a proton, make N 14 , put out a neutron. We know now, and Oppie should -well, it's all of us; it's a long story -we know now that the neutron is heavier than the proton.…”