He was appointed as Radium and X-ray physicist to the Canadian National Research Council in 1930. In 1939–40 he attempted to build a graphite-uranium reactor in Ottawa, anticipating Enrico Fermi 's work by several months. In 1942 he joined the Anglo-French nuclear research team at the Montreal Laboratory, where he was responsible for recruiting Canadian scientists. The laboratory later transferred to the Chalk River, and built the ZEEP Reactor, the first outside the U.S.A.