Detector development for a high-flux neutron reflectometer

Neutron reflectometry is a powerful tool for investigating the surface and interfacial structures of various materials on the nanometer to submicrometer spatial range. We have been developing a horizontal-type neutron reflectometer, named SOFIA, at BL16 in J-PARC/MLF for investigating such interfacial structures, including those of free liquid surfaces. Utilizing the high-flux neutron beam at J-PARC, we have, until now, efficiently performed reflectivity measurements with SOFIA. However, the maximum count rate of the two-dimensional (2-D) detector currently in use will be insufficient for the full-power operation of J-PARC (1 MW) in the near future. In order to increase the count rate, we developed a new detector comprising 21 one-dimensional (1-D) detectors. 1-D detectors were used because neutron counts for a two-dimensional (2-D) detector can be reduced by dividing it into an array of 1-D detectors. In this study, we evaluated the performance of the newly developed detector and successfully carried out neutron reflectivity measurements using it.