Year
1997
Abstract
A detector and front-end electronics unit with secure data transmission has been designed and implemented for a fissile mass flow monitoring system for monitoring fissile mass flow of gasses and liquids in a pipe. The detector/electronics unit consists of four bismuth germanate (BGO) scintillation detectors, pulse-shaping and counting electronics, local temperature sensors and onboard local area network nodes which locally acquire data and report to the master computer via a secure network link. The signal gain of the pulse-shaping circuitry and energy windows of the pulse-counting circuitry are periodically self calibrated and self adjusted in situ using a characteristic line in the fissile material pulse height spectrum as a reference point to compensate for drift such as that in the detector gain due to photomultiplier tube aging. The temperaturedependent signal amplitude variations due to the intrinsic temperature coefficients of the photomultiplier tube gain and BGO scintillation efficiency have been experimentally characterized and real-time gain corrections have been introduced. The detector and electronics design, measured intrinsic performance of the detectors and electronics and the performance of the detector and electronics units within the fissile mass flow monitoring system are described.