Neutron Measurements with Boron-Trifluoride Counters

Passing of the Last of the Three Who Established14C Dating: A Historical Footnote

“…The principal author of that article was Serge Alexander Korff [1906Korff [ -1983, who, at this time, was studying the physics of cosmic rays. As Libby expressed it: "As soon as I read Korff's [1939] paper, where he'd found neutrons in cosmic rays, that's carbon dating" (Libby 1979:33, 40). The article was Korff and Danforth (1939).…”

Radiocarbon Dating: Development of a Nobel Method

“…The decrease at the top of the atmosphere was attributed to the escape into space of some of the neutrons so formed (Libby 1952). Korff noted that the neutrons that remained would be slowed down by collisions with atmospheric gas nuclei and that these "slow" or thermal neutrons would disappear by being captured by nitrogen to form 14 C. This was apparently the first published prediction that 14 C should exist in nature (Korff and Danforth 1939;Montgomery and Montgomery 1939;Korff 1940;Libby n.d.). Four decades later, Libby stated that the origin of his conceptualization of 14 C dating involved his reading of the Korff and Danforth (1939) publication which reported finding neutrons in the atmosphere: "As soon as I read Korff's paper … that's carbon dating" (Libby 1979).…”

Radiocarbon Dating and Intercomparison of Some Early Historical Radiocarbon Samples

“…That this rumor has some credibility is perhaps due to the fact that Fermi’s 1938 Nobel Prize was for the discovery of nuclear reactions induced by slow neutrons which, of course, is how most natural 14 C is produced. Those accepting that interpretation of the origin of the idea of 14 C dating might wish to take into consideration a later statement of Libby that the idea for 14 C dating came to him in 1939 after reading an article by Serge Korff (Korff and Danforth 1939) reporting that there were free neutrons existing in the upper atmosphere (Libby 1979:33, 40). Libby already knew from his residence at Berkeley in the 1930s, that colleagues there had determined that the most favored means of producing 14 C was by neutrons on 14 N and that, theoretical reasons to the contrary, 14 C was a “long-lived [carbon] isotope” (Kamen 1963).…”