Development of energy-resolved neutron imaging detectors at RADEN
Energy-resolved neutron imaging at a pulsed source utilizes the energy-dependent neutron transmission measured via time-of-flight to extract quantitative information about the internal microstructure of an object. At the RADEN instrument at J-PARC in Japan, we use cutting-edge detectors employing micro-pattern detectors or fast Li-glass scintillators and fast, all-digital data acquisition to perform such measurements, while continuing their development toward better utilization of the intense neutron source. In particular, for the Micro-Pixel Chamber based Neutron Imaging Detector (μNID), a micro-pattern detector with a 400 μm pitch and employing 3He for neutron conversion, we have successfully improved the spatial resolution from 200 to 100 μm, increased the detection efficiency from 18 to 26% for thermal neutrons, and increased the maximum count rate from 0.4 to 1 Mcps. We are also testing a new readout element with a 215 μm pitch for further improved spatial resolution, and a μNID with boron-based neutron converter for increased rate performance.