Who Invented the Trinity Nuclear Test’s Christy Gadget? Patents and Evidence from the Archives

The Christy Gadget is the informal name for plutonium device detonated in Trinity test on July 16, 1945. In September 1944, Robert Christy, working theoretical implosion group, proposed a novel concept that altered design of nuclear core Fat Man. While scientists originally intended to use hollow sphere plutonium, this entailed substantial risk due likelihood asymmetries resulting from implosion. changing solid with modulated neutron source, and was eventually adopted, tested at Trinity, used attack Nagasaki. there no question regarding important role played demonstrating its feasibility as reliable design, debate who initially idea; though most sources have attributed invention some historical credit Christy’s group leader, Rudolf Peierls, or indeed other scientists. This paper seeks outline resolve dispute. We present new unclassified evidence extracted previously unavailable (to audiences) National Security Research Center archives Los Alamos Laboratory. consists 1945–1946 patent documentation, oral history interview tapes monthly 1944 progress reports Theoretical Division. Though Peierls share joint patent, both Peierls’ words writings, together Hans Bethe Edward Teller, support traditional view originator idea. does deserve majority we acknowledge von Neumann development.