Electronic support system enhancements for micro-pocket fission detectors (MPFDs)

Abstract

Micro-Pocket Fission Detectors (MPFDs) continue to be an important development in advancing nuclear research capabilities. Commonly, nuclear reactor cores are located far from the location which is desired for read-out electronics. For example, the core of the TRIGA Mk II research nuclear reactor at Kansas State University is submerged under approximately 16 feet of water. Research nuclear reactor facilities often possess unanticipated sources of noise due to the aging facilities, electronic pump and compressor motors, and electromechanical control systems. A robust method to transmitMPFD pulse signals from the MPFD sensors to the readout electronics is under development. Numerous pre-amplifiers were tested to determine the preferred signal processing method for MPFDs. An MPFD emulator was developed which enabled benchtop electronics testing and optimization of the pre-amplifier circuit for future MPFD sensor testing. Finally, an MPFD was constructed and tested at the Kansas State University TRIGA Mk. II nuclear research reactor with the preferred electronics and compared to the MPFD emulator. Emulated pulses were produced with an amplitude of 144 mV and a rise- time of 115 ns using a shaping time of 0.25μs and gain of -1.3. Similarly, neutron-induced pulses were observed with an amplitude of 116 mV and a rise-time of 316 ns using a shaping time of 1.0μs and a gain of -1.3.The improved electronics increased the signal-to-noise ratio for the neutron-induced signal from approximately 2 to approximately 5.