Jersey. Prospecting in Oklahoma In Tulsa, Pontecorvo went to work for two European migrants, Jakov "Jake" Neufeld and Serge Alexandrovich Scherbatskoy, who had founded a company called Well Surveys with funds provided by Standard Oil. Their idea was to apply nuclear physics to searching for minerals. A gamma ray device had been successful at analysing rock outcroppings. Inspired by the work done in Italy and France, they reasoned that neutrons, being without electrical charge, might be able to detect different elements beneath the surface by inducing radioactivity on the rocks. In Pontecorvo, they had the expert they needed. Pontecorvo created a neutron source using radium and beryllium, as the Via Panisperna boys had, with paraffin wax as a neutron moderator, and measured the absorption of different minerals using methods developed by Fermi and Amaldi. By June 1941, he had a device that could differentiate shale, limestone and sandstone, and map the transitions between them. The technique may be considered the first practical application of the discovery of slow neutrons, and would still be in use decades later for well logging. He filed four patents relating to his instrumentation. By late 1941, Pontecorvo was having difficulty securing the radioisotopes that he needed. Unbeknown to him, the Manhattan Project, the wartime effort to build atomic bombs, was cornering the market. In an attempt to obtain them, he met with Fermi, von Halban and George Placzek in New York in April 1942. He was unable to secure the supplies he wanted, but Fermi showed an unexpected keen interest in the Wells Surveys work. Tube Alloys The meeting with Fermi yielded no supplies, but it did result in Pontecorvo receiving an offer from von Halban and Placzek to join the Tube Alloys team at the Montreal Laboratory in Canada. There was some concern from Sir Edward Appleton over his appointment, not because of Pontecorvo's political beliefs, but on account of the fact that he was not a British national, and there were already a large number of foreign scientists working on Tube Alloys. Appleton was ultimately persuaded due to Pontecorvo's reputation, and the fact that good physicists were in short supply. Pontecorvo was officially appointed to Tube Alloys on 15 January 1943, and arrived in Montreal with his family on 7 February 1943. The Montreal team designed a nuclear reactor using heavy water as a neutron moderator, but lacked the quantity of heavy water