Accepted manuscript "Re-calculation of air kerma to dose equivalent conversion coefficients for mono-energetic photons"

This is the accepted version of the article after peer review process, as submitted to Journal of Radiological Protection.  IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.  The final published version of this article is available online at DOI 10.1088/1361-6498/adda56.  

Title: Re-calculation of air kerma to dose equivalent conversion coefficients for mono-energetic photons

Abstract: This work presents new calculations of conversion coefficients (CCs) from total air kerma to dose equivalent quantities H'(0.07), H'(3), H*(10), Hp(0.07), Hp(3), and Hp(10) for area and personal dosimetry for mono-energetic photons in the energy range from 2 keV to 50 MeV, assuming secondary charged particle equilibrium. Calculations using the MCNP Monte Carlo code were performed for a large number of photon energies with the aim to prevent errors resulting from possible improper interpolation between currently available sparsely spaced CC values, when an average CC value over a photon fluence spectrum needs to be determined. The CC values were compared with the values published in the ISO 4037 3:2019 standard. A very close agreement was achieved for the majority of CCs. Larger discrepancies were found for some CCs, often for low photon energies or large angles of radiation incidence, which were taken from older publications or when CC values were interpolated or extrapolated. Furthermore, some differences were found in the MeV energy range which are significant for dosemeter calibrations, e.g., the presented values of CC to H*(10) for the main photon energies of 137Cs and 60Co radionuclides are both lower by 2.8 %. Finally, it was found that the values of CCs to Hp(0.07; E, )slab given in ISO 4037 3:2019 were not taken from the source publication correctly. In conclusion, the CC values given in ISO 4037 3:2019 should be updated in view of the results obtained.