NEUTRON-FIELD AND INDUCED-ACTIVITY MEASUREMENTS-OPERATION BREN

Operation BREN (Bare Reactor Experiment, Nevada) was an experiment that used a 1500-ft tower and a bare (no shielding) fast nuclear reactor patterned on 'Godiva' to simulate a nuclear weapon detonated at various heights above the ground. Certain characteristics of the neutron field from this unshielded reactor were measured. The activation of gold, manganese, sulfur, cadmium-covered gold, and cadmium-covered manganese was determined as a function of distance from the reactor and of depth in the ground. The data show how those parameters, important for calculating neutron-induced activity in the soil, vary as a function of the height of the source and the slant range from the source.