Fabrication of Small-Period Neutron Absorption Grating by Pressurized Particle Filling Method

Neutron absorption gratings play a crucial role in neutron phase contrast imaging systems, where the fabrication of large-size and small-period absorption gratings that meet imaging requirements presents a significant challenge. The pressurized particle filling method has been successfully applied to fabricate large-size absorption gratings. Here, we investigated the feasibility of the pressurized particle filling method for fabricating small-period gratings and proposed an optimized pressurized particle filling method. The grating surface was covered with a uniform particle layer and then pressurized, utilizing the adaptive deformation of the particle layer to achieve uniform particle filling. Neutron absorption gratings with an area of 60 × 60 mm2 and periods of 8 and 4 µm were fabricated through this method. The particle filling rate and fabrication efficiency were successfully improved. In addition, the evaluation of the particle filling uniformity method by analyzing the proportion of particles on the grating surface was proposed. The better uniformity of small-period neutron absorption gratings indicated that the optimized pressurized particle filling method can achieve relatively uniform particle filling.