FPGA-based random pulse generator for emulation of a neutron detector system in a nuclear reactor

In this work an FPGA-based emulator of a pulse-mode neutron detector system is presented. The equipment emulates the digital output of a discriminator circuit and permits the generation of pulse trains ranging from 0.5 pulse/s to 1 Mpulse/s. The emulation is based on a synchronous version of a Poisson process generator using Bernoulli trials. The emulator is controlled via a serial connection to a computer and both the pulse-width and the mean pulse-rate can be dynamically updated; thus, making possible the emulation of a detector evolution when a nuclear reactor is in its start-up/shutting-down phase. To also consider the dead-time effects present in pulse-mode detector systems, the equipment implements the paralyzable and nonparalyzable dead-time models. The emulator also incorporates a data-logger module to record interarrival-time values of the generated pulse train. This last feature can be used to calibrate a rate-meter equipment and to verify the statistics of the emulator´s output signal.