The energy-resolved neutron imaging system, RADEN, has been installed at the pulsed neutron source in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. In addition to conventional neutron radiography and tomography, RADEN, the world’s first imaging beam-line at a pulsed neutron source, provides three main options for new, quantitative neutron imaging techniques: Bragg-edge imaging to visualize the spatial distribution of crystallographic information, resonance absorption imaging for elemental composition and temperature information, and polarized neutron imaging for magnetic field information. This paper describes the results of characterization studies of the neutronic performance and installed devices at RADEN and shows the results of several demonstration studies for pulsed neutron imaging.

This study presents a significant development in the Energy-Resolved Neutron Imaging System RADEN, in the Japan Proton Accelerator Research Complex, Japan. Through a systematic study, the collimation power of the facility was reevaluated. What was initially considered to be values of 230, 420, and 760 have been proven to be much higher. To perform the calculation of the L/D factor of the beam, a state-of-the-art method has been used, along with a standard reference sample to measure the resolution of neutron images. To add robustness to the results, the study compares five different scintillators of different composition and thickness [6LiF:ZnS(Ag) of 50, 100, 200, and 300 μm and Gd2O2S of 50 μm]. The calculated collimating power of the beam ranges between 470 and 1520. These results place a spotlight on an existing discrepancy between the geometrically calculated L/D and the actual measurable quantity, as well as highlight the superior performance of the RADEN beamline.

At the RADEN beam line of the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, we combine cutting-edge, event-type imaging detectors with a high-intensity, pulsed neutron beam to perform energy-resolved neutron imaging. In particular, the µNID (Micropixel-chamber-based Neutron Imaging Detector), with its unique combination of a large 10 cm × 10 cm field-of-view, 100 µm spatial resolution, and recent improvements in the rate performance to over 1 Mcps, is quickly becoming the main event-type detector for such measurements at RADEN. To improve the ease-of-use of the µNID system, we have recently redesigned the control hardware and software to allow full integration into the RADEN experiment control system and developed a web-based user interface for data processing. Further development efforts for the µNID, including a new reduced-pitch readout for improved spatial resolution and a boron-converter based µNID that achieves a count rate of over 20 Mcps, are also ongoing. In addition, we are studying super resolution methods to improve the spatial resolution of a lithium-glass scintillator pixel detector.