Geant4 and MCNPX simulations of thermal neutron detection with planar silicon detectors

We used Geant4 and MCNPX codes to evaluate the detection efficiency of planar silicon detectors coupled to different Boron-based converters with varied compositions and thicknesses that detect thermal neutrons via the 10B(n,α)7Li nuclear reaction. Few studies about the thermal neutron transport in Geant4 have been reported so far and it is becoming increasingly difficult to ignore its discrepancies with MCNPX in this neutron energy range. In the thermal energy range, Geant4 shows high discrepancies with MCNPX giving a maximum efficiency of about 3.3% in the 10B case whereas that obtained with MCNPX was 5%. Disagreements obtained between both codes in this energy range are analyzed and discussed.