Neutron imaging detector based on the μPICμPIC micro-pixel chamber

We have developed a prototype time-resolved neutron imaging detector employing the micro-pixel chamber (μPICμPIC), a micro-pattern gaseous detector, coupled with a field programmable gate array-based data acquisition system for applications in neutron radiography at high-intensity neutron sources. The prototype system, with an active area of 10×10 cm2 and operated at a gas pressure of 2 atm, measures both the energy deposition (via time-over-threshold) and three-dimensional track of each neutron-induced event, allowing the reconstruction of the neutron interaction point with improved accuracy. Using a simple position reconstruction algorithm, a spatial resolution of 349±36μm was achieved, with further improvement expected. The detailed tracking allows strong rejection of background gamma-rays, resulting in an effective gamma sensitivity of 10−12 or less, coupled with stable, robust neutron identification. The detector also features a time resolution of 0.6μs.