A neutron source detector is provided for detecting and determining an energy spectrum of a neutron source and a direction to the neutron source. The neutron source detector includes a detection system configured to detect and record the location and energy of interaction between a detector and a recoil proton produced by a scattering of a neutron emitted by the neutron source. A processor is configured to determine the energy of each of a plurality of recoil protons produced by respective scatterings of a neutron based on the recorded locations and energies of interactions of the recoil protons and determine and order scatter locations of the scattered neutron based on the determined energies of the recoil protons. A direction of the scattered neutron is determined based on the order of the scatter locations. The direction to the neutron source is determined based on the determined directions of a plurality of scattered neutrons, and the energy spectrum of the neutron source is determined based on the determined direction to the neutron source, the determined directions of the plurality of scattered neutrons, and the determined energies of the plurality of recoil protons produced by the respective plurality of scattered neutrons.