Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian physicist. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first experimentally detected the fission by-products. Later, with his collaborator Rudolf Peierls[1] he designed the first theoretical mechanism for the detonation of an atomic bomb in 1940.https://en.wikipedia.org/wiki/Otto_Robert_Frisch