Characterization of a neutron calibration field with ²⁴¹Am-Be source using Bonner sphere spectrometer

This paper presents the characterization of a neutron calibration field of a ²⁴¹Am-Be source using Bonner sphere spectrometer. The characterization of the neutron field in terms of neutron ambient dose equivalent, H^*(10), rates and neutron flux spectra was performed using generalized-fit and semi-empirical fit methods together with an unfolding technique using the MAXED code. Monte Carlo simulations using MCNP5 have also been conducted to qualify the characterization process. Comparison of the neutron fluxes and the H^*(10) rates obtained from the various methods shows that the components of the neutron fluxes are in good agreement with a discrepancy of about 2% while the discrepancy of the direct H^*(10) rates is within 3%. This good agreement among the methods indicates the reliability of the characterization process for practical calibration of neutron measuring devices. The results also suggest that the calibration should be conducted at a distance less than 200cm to ensure the contribution of the scattered component in the reading of the device less than that of the direct component by 40%.