Our History - Los Alamos National Laboratory

“We are free to start things, free to go aboutthem, but then the rock of what the world isreally like limits and shapes this freedom. ”J. Robert OppenheimerAugust 1944 reorganizationDuring the first six months of the Laboratory, the gun method of assembly was the focus ofadministrative and technical activities in the ordnance program. By February 1944 . . .sufficiently accurate calculations had been made so that, for the U 235 gun, Group T-2 specifiedthe actual bore. During the period to August 1944 the main focus of activity was the plutonium.gun. In the summer of 1944 . . . when the first Clinton plutonium made by chain reactorarrived-much more heavily irradiated than the previous samples made by cyclotronbombardment—the existence of Pu 240was verified, as was the fear that it might be a strongspontaneous fissioner. Neutron background in the plutonium which would be produced at fullpower was punched up into the region where, to prevent predetonation, assembly velocitieswould have to be much greater than those possible with the plutonium gun. The implosion wasthe only hope, and from current evidence a not very good one. It was decided to attack theproblems of the implosion and with every means available. “to throw the book at it. ”Administratively, the program was taken out of the Ordnance Division and divided betweentwo new divisions. One of these was to be concerned primarily with the investigation ofimplosion dynamics. the other primarily with the development of adequate HE [highexplosives] components.Hawkins, Project Y. Chapter IV,LOS ALAMOS SCIENCE Winter/Spring 1983