Development of a Two-Dimensional Gaseous Detector for Energy-Selective Neutron Radiography

Energy-selective neutron radiography is a new method for studying the fine structure of heavy materials by using pulsed neutron sources. To perform such radiography, precise measurements of temporal information and twodimensional position are essential. Therefore, we developed a gaseous neutron detector using the gas electron multiplier (GEM). In addition, to detect neutrons, a single surface of an aluminium cathode plate and both surfaces of two GEM foils were coated with boron-10. Two normal GEM foils were stacked in a chamber for gas amplification. An anode plate with two-dimensional strips (0.8-mm pitch) was mounted in order to precisely reconstruct neutron incident positions. To allow high-speed data transfer, a compact readout system with new application-specific integrated circuit (ASIC) chips and a field programmable gate array (FPGA) was developed. Finally, several beam tests were conducted with pulsed neutron sources and two interesting applications were demonstrated.