Establishment of a low-energy X-ray narrow-spectrum series calibration field based on ISO 4037:2019 standard series

Tsuji, Tomoya  ; Yoshitomi, Hiroshi  ; Sato, Fuminobu*; Tanimura, Yoshihiko   

Radiation dosimeters must be well calibrated and tested according to international standards. In the ISO 4037:2019 standard series, requirements regarding photon calibration fields to be used are clearly specified. The X-ray narrow-spectrum series (N-series) calibration field is commonly used to test energy response of dosimeters. Thus, we established an N-series calibration field using a soft X-ray generator, YXLON MG165/4.5, at the Facility of Radiation Standards (FRS) of Japan Atomic Energy Agency (JAEA). The radiation quality of an X-ray calibration field is characterized by the following parameters: mean energy of a beam, resolution of X-ray spectral fluence, half-value layer (HVL) of Al or Cu filters with respect to air kerma and homogeneity coefficient. The established calibration fields were verified to ensure that these parameters were in accordance with the recommendations of the ISO 4037-1:2019 based on measurements.