An inventive neutron detector includes an n-type GaN wafer and a photomultiplier, which are optically coupled with each other. The n-type GaN wafer is irradiated with neutrons from a neutron source, such as including a particle accelerator and a beryllium target. Scintillation of the n-type GaN resulting from the neutron irradiation is amplified by the photomultiplier and is analyzed using a data acquisition system.