Year
1971
Abstract
The purpose of a safeguards monitor is to prevent the accidental or intentional diversion of special nuclear materials. The monitor must nave high sensitivity for the radiometric scanning of items passing through it, and must have a fast response time. The personnel monitor designed at Rocky Plats meets these requirements by using two 24-inches \"by 5-inches by 2-inches plastic scintillators which are sensitive to both gamma and neutron radiation. The electronics used with these plastic scintillators consist of the standard photomultiplier, preamplifier, amplifier, and single channel analyzer combination. The output pulses are fed to an averaging integrator which compares the immediate count rate observed while a person is walking past the monitoring station to a current history of the time averaged background count rate. Statistical differences between the two rates cause, an alarm to be sounded. Ratemeters, sealers, or graphical plotters may be incorporated if desired to give a visual presentation of the count data. Experimentally, the monitor will respond to 1/16th inch brass shielded source of less than 0.5 gram plutonium-239 when carried by a person running between the detectors.