Irène Joliot-Curie
Rutherford's conjecture was not widely accepted. In his 1931 monograph on the "Constitution of Atomic Nuclei and Radioactivity", George Gamow, then at the Institute for Theoretical Physics in Copenhagen, did not mention the neutron. At the time of their 1932 measurements in Paris that would lead to the discovery of the neutron, Irène Joliot-Curie and Frédéric Joliot were unaware of the conjecture.