ISO 4037 Narrow spectrum X-ray reference field

Abstract

Characterization of the ISO-4037 narrow spectrum (N-series, “series” stands for the maximum spectral energy in keV) X-ray reference field has been performed. In details, radiometric (i.e., mean energy, spectral resolution, half-value layer, beam homogeneity coefficient) and physical (air Kerma rate) parameters have been investigated for different N-series X-ray beam qualities (i.e., N-40, N-60, N-80, N-100, N-120, and N-150) using either simulation-based and theoretical calculations or experimental measurements. In addition, the dosimetric conversion coefficients from air kerma to ambient dose equivalent and to personal dose equivalent at the normal incident angle have been deduced, and the combined standard uncertainties of investigated quantities were evaluated or estimated, whenever possible. The simulated and experimental data obtained from this work demonstrated good agreement and were consistent with reference data published in the ISO-4037 series and with those reported by the German primary standard dosimetry laboratory, indicating the reliability of the present findings. A comparison with data from other international standard dosimetry laboratories revealed a few anomalous values. It is recommended that these discrepancies should be further investigated and re-evaluated to ensure the consistency and accuracy of related calibration procedures.