We demonstrate the potential of neutron systems for detecting microscale defects in a thin epoxy adhesive layer between two metal plates. Neutron tomography has been used to ascertain the internal structure of the adhesive layer. The distribution of defects including microvoids is found in three-dimensionally reconstructed models that are obtained from neutron tomography images and is compared with that obtained from a magnified real image of the layer. From the results, we find that a neutron system can be the most suitable tool for detecting microscale defects in a thin adhesive layer that lies between two high X-ray attenuation plates