Cosmic-ray neutrons are high-energy neutrons that originate from outer space and interact with the Earth's atmosphere, producing secondary particles. These neutrons can penetrate the Earth's surface and provide valuable information about underground structures, such as soil moisture content, snow depth, and geological features. In recent years, cosmic-ray neutrons have been utilized in various research fields, including hydrology, geophysics, and agriculture, to monitor environmental changes and improve our understanding of the Earth's subsurface.