Abstract:Neutron energy spectrum measurement is an important research topic in the field of nuclear radiation detection. It plays an important role in the whole neutron radiation protection detection and is closely related to the neutron radiation dose. Multi-sphere neutron spectrometer is a common tool for neutron spectrum measurement. It has many advantages. First of all, it is simple and convenient to operate. Secondly, it is powerful, mainly in the measurement range, which is much larger than other similar equipment. Finally, he is very good at sensitivity. In this paper, water and polyethylene are used as the moderators of multi-sphere neutron spectrometers respectively, and the Monte Carlo program Geant4 is used to calculate the response functions of 60 energy points in the energy range of 10-9 MeV to 102 MeV, and the neutron response function curves of the two kinds of multi-sphere neutron spectrometers are compared. Using the Gravel few-channel spectrum unfolding algorithm, we measured data of the water moderator multi-sphere neutron spectrometer in different neutron fields. The spectrum unfolding results show that it is feasible to use water as the moderator of the multi-sphere neutron spectrometer. The research results provide a theoretical and simulation basis for the use of water as a moderator in equipment.