Neutron energy spectrum in a reactor exit channel with a single surface barrier sensor using GEANT4

A single surface barrier neutron spectrometer has been used to characterise the neutron energy spectrum at the neutron irradiation channel of a nuclear reactor. The response functions of a single surface barrier detector associated with a natural boron neutron-charged particle converter were calculated using the GEANT4 simulation toolkit. Calculations were performed for thermal, intermediate energy and fast neutrons and for four converter thicknesses from 50 μg cm−2 to 3.26 mg cm−2. The relationship between the response functions and the energy loss of the charged particles emitted by the 10B(n,α)7Li reaction in the converter as a function of incident neutron energy is discussed. Finally, the neutron energy spectrum at the neutronography irradiation site of the Algerian Research Reactor NUR was determined using the experimentally determined pulse height spectrum of the single surface barrier spectrometer with the help of the calculated response functions and an efficient unfolding code.