A neutron monitor for continuous neutron flux monitoring in particle accelerator facility

A BF3 counter based neutron monitor is designed to monitor the neutron flux in the area having particle accelerator installations where continuous neutron flux monitoring is required. The system consists of a BF3 proportional counter, a high density polythene moderator, a charge sensitive preamplifier, control unit for display of neutron flux and a micro controller based interface for connectivity to the central monitoring console. LND make 15mm dia x 150 mm BF3 counter tube with 200 torr BF3 gas pressure is used for the detection of thermal neutrons. A high density polythene moderator of 150 mm dia x 200 mm height is used for thermalising the fast neutrons. A charge sensitive preamplifier amplifies the signal from the counter and transmits to the main unit. The main unit consists of a discriminator for discriminating the noise and any contribution from the gamma rays background. The standard pulse height and width signal is then converted into an analog signal by a frequency to voltage convertor. This analog signal is proportional to the count rate of the counter signal. As the range of the monitor is 0 to 5000 N/sqcm /sec, the count rate is displayed on the log scale of a 0-1 mA fsd analog meter. A log amplifier having 3 decades is used to convert the analog signal to logarithmic scale. A micro controller based interface is incorporated for the connectivity to the main console as well as it provides a remote display and alarm settings with audio visual annunciation. (author)