Year
1974
Abstract
A fission multiplicity detector (FMD) system has been developed for the passive assay of the plutonium content of known isotopic composition in low-level hydrogenous waste materials contained in 55-gallon drums. It utilizes the fact that 240pu emits an average of seven prompt gamma rays and 2.5 neutrons per spontaneous fission event. The system was specifically designed to combine rugged mechanical construction and simplicity of operation with sensitivity to 1 g of fissile Pu, corresponding to 0.1 to 0.2 g of 240pu> as well as the ability to function in a high background environment, while providing good spatial uniformity of the detector response. It consists of a barrel-handling assembly, the FMD, and electronic logic interfaced into a programmable desk calculator for data acquisition and reduction.