Neutron spectrometry of D2O-moderated 252Cf with Bonner sphere spectrometer

For neutron spectrometry of the D2O-moderated 252Cf source with a Bonner sphere spectrometer (BSS), it is difficult to use the large and heavy shadow cone to correct the neutron scattering effect. To overcome this problem, Monte Carlo (MC) simulation method was applied to calculate the neutron scattering ratio and to establish the BSS response functions. The simulated response functions were verified by experimental measurements in reference mono-energetic neutron fields. MC simulation based scattering-correction was validated by measurement of 252Cf neutron field. The measured and simulated values of the neutron scattering ratio were very close with relative errors within ±6%. Finally, the neutron spectrum and the spectrum averaged conversion coefficients of the D2O-moderated 252Cf were measured using BSS after scattering-correction by MC simulation, and the results agreed with the values recommended by ISO 8529–1:2021. It shows that the MC simulation can be a useful substitute to shadow cones method for neutron scattering-correction. •D2O-moderated 252Cf spectrum was measured by a Bonner sphere spectrometer.•The response functions were verified in reference mono-energetic neutron fields.•MC simulation based scattering-correction was validated in 252Cf field.