Nanoscale Gd2O2S:Tb Scintillators for High-Resolution Fluorescent Imaging of Cold Neutrons

Cold neutron has a strong ability to penetrate metal materials and identify light elements, making it an ideal nondestructive testing technique for detecting cracks, bubbles, or other defects in metals. However, the low imaging resolution and detection efficiency of scintillators limit the application of cold neutron technology in imaging. The particle size and luminescence properties of scintillator materials have an important influence on the spatial resolution and detection efficiency of cold neutron radiography. Here, we report a series of NaF-doped Gd2O2S:Tb3+ (NaF-d-GOS:Tb) scintillators with adjustable particle size, which were prepared through a two-step method of solution precipitation followed by solid-phase vulcanization calcination. It was found that the NaF-d-GOS:Tb scintillators showed the highest quantum yield, reaching up to 62.94%. They were applied to fabricating cold neutron ultrathin screens. The resolution can reach 12 μm in the cold neutron imaging system. These NaF-d-GOS:Tb scintillators with excellent fluorescence facilitate the development of nondestructive testing techniques based on cold neutron imaging.