Roentgen (unit) capped at 3 MeV in 1950. The USSR all-union committee of standards (GOST) had meanwhile adopted a significantly different definition of the roentgen in 1934. GOST standard 7623 defined it as "the physical dose of X-rays which produces charges each of one electrostatic unit in magnitude per cm of irradiated volume in air at 0 °C and normal atmospheric pressure when ionization is complete." The distinction of physical dose from dose caused confusion, some of which may have led Cantrill and Parker report that the roentgen had become shorthand for 83 ergs per gram (0.0083 Gy) of tissue. They named
Harley A. Wilhelm Mallinckrodt, Union Carbide and DuPont began producing uranium by the Ames process, and Ames phased out its own production by early 1945. The Ames Laboratory also produced of extremely pure cerium for the cerium sulphide crucibles used by the plutonium metallurgists. Fears that world supplies of uranium were limited led to experiments with thorium, which could be irradiated to produce fissile uranium-233. A calcium reduction process was developed for thorium, and produced some . After World War II, Spedding and Wilhelm founded the Institute of Atomic Research and the Ames Laboratory of the Atomic Energy Commission. Wilhelm became its associate