A neutron elastic scattering detector device for non-invasively detecting the presence of at least one predetermined element of an object of interest. The detector device comprises a neutron source that simultaneously outputs, at a creation time, a neutron in a first direction and an associated baseline particle in a second direction. The first direction is opposite of the second direction. The neutron can impinge upon the predetermined element of the object of interest and scatter therefrom in a third direction. A baseline particle detector system detects the baseline particle and outputs a baseline signal characteristic thereof. A neutron detector system detects the neutron and outputs a scattering signal in characteristic thereof. The processing unit analyzes the baseline signal and the scattering signal to determine the presence of the predetermined element.