Signal processing system based on FPGAs for neutron imaging detectors using scintillators

A signal processing system based on field programmable gate arrays (FPGAs) was developed for a 64 channel×64 channel neutron imaging device using a wavelength shifting fiber read-out based on a photon-counting method. Light signals detected by 64 channel multi-anode photomultipliers are amplified and converted to digital photon signals containing incident-position and time information of neutron by using high-speed amplifiers and discriminators. By using coincidence circuits made in FPGAs, the incident position of neutron is determined based on these digital signals. A neutron imaging detector composed of the signal processing system and a neutron imaging device with a ZnS:Ag/6LiF scintillator was evaluated by using neutron beam. It was confirmed that the signal processing based on FPGAs was effective to determine a precise incident position of neutron with high speed and many channel.