 Archie was therefore adopted, although the scarcity of units in August 1944 precluded wholescale destructive testing.Testing of Silverplate Boeing B-29 Superfortress aircraft with Thin Man bomb shapes was carried out at Muroc Army Air Field in March and June 1944.At a meeting of the S-1 Executive Committee on 14 November 1942, Chadwick had expressed a fear that the alpha particles emitted by plutonium could produce neutrons in light elements present as impurities, which in turn would produce fission in the plutonium and cause a predetonation, a chain reaction before the core was fully assembled.