the nested neutron spectrometer (nns) is a tool used for neutron spectroscopy. the nns is used to measure the energy spectrum of neutrons in a neutron field. this type of detector is used in both research facilities (for characterization of neutron fields) and workplaces, where neutron radiation maybe encountered, for radiation protection purposes. due to the difficulty associated with the detection of neutrons, the nns is one of the few pieces of equipment capable of accurately determining the characteristics of a neutron field.