Results of the proficiency test for the <i>Ka</i> CMC of the SSDL-ININ Mexico, for diagnostic radiology IEC 61267:2005 and radiation protection ISO 4037:2019 X-ray beam qualities

The present work describes the results for the bilateral comparison between the Secondary Standards Dosimetry Laboratories of the Instituto Nacional de Investigaciones Nucleares (SSDL-ININ), Mexico, and the pilot laboratory, the Centro de Protección e Higiene de las Radiaciones (SSDL-CPHR), Cuba, for the realization of the air kerma (${\boldsymbol{K}}_{\boldsymbol{a}}$) quantity to: (i) diagnostic X-ray (DXR) IEC 61267:2005 beam qualities: RQR 5 RQR 9, RQT 8, and RQT 9 and (ii) radiation protection (RP) ISO 4037:2019 X-ray beam qualities: N60, N100, and W60, as well S-Cs for gamma radiation. The matched and characterized reference fields are realized at SSDL-ININ with a Toshiba E7252FX X-ray tube. In all cases, the ${\boldsymbol{K}}_{\boldsymbol{a}}$ measurements are traceable to PTB, except for S-Cs, traceable to ININ. The SSDL-CPHR realizes its reference radiation beam qualities also as matched reference fields with a Pantak HF160C X-ray tube. For the S-Cs beam quality, the CPHR uses a Buchler OB6 irradiator; the ININ, a Siemens Cesagammatron. The transfer ionization chambers calibrated in the RQR and RQT qualities are an Exradin A650/DO70312; for the RQT qualities for CT, a PTW 30009/0655 and RC3CT/9217 were calibrated; and for the RP X-ray qualities, the Exradin A650/DO70312 and a PTW 32002/073 were calibrated. The ratio ${\boldsymbol{R}}_{\boldsymbol{k}}$ of the resulting calibration coefficients ${\boldsymbol{N}}_{{\boldsymbol{K}}_{\boldsymbol{a}}}$ of each SSDL of the RQR qualities are consistent within the $\boldsymbol{U}\left(\boldsymbol{k}=\mathbf{2}\right)\%$ ≤ 2.3%; for the RQT qualities, the differences are less than the $\boldsymbol{U}\left(\boldsymbol{k}=\mathbf{2}\right)\%$ ≤ 3.6%; and for the RP X-ray qualities, within the order of $\boldsymbol{U}\left(\boldsymbol{k}=\mathbf{2}\right)\%$ ≤ 3.5%. For the S-Cs quality, the ${\boldsymbol{R}}_{\boldsymbol{k}}$ is in the order of $\boldsymbol{U}\left(\boldsymbol{k}=\mathbf{2}\right)$ ≤ 3.0%. It should be noted that the ININ U's are generally larger due to the failure of the ${\boldsymbol{k}}_{\boldsymbol{TP}}$ correction factor, a brief discussion is given here. The ${\boldsymbol{E}}_{\boldsymbol{n}}$ score from ISO 17043 provides statistical support to this comparison.