Study of the uncertainty of measurements of gamma radiation from Cesium-137 and Cobalt-60 sources

Radiation dosimetry is a key element in medical, industrial, and scientific activities involving the use of ionizing radiation. Accurate measurements of radiation doses ensure the safety and effectiveness of radiological practices, which is critically important for protecting patients during medical procedures, adhering to industrial safety standards, and conducting scientific research. International studies are carried out to achieve this high measurement accuracy. The National Scientific Centre “Institute of Metrology” (NSC “Institute of Metrology”) actively participates in international projects aimed at improving the accuracy and consistency of radiation dosimetry. These projects unite National Metrology Institutes (NMIs) to standardize measurement and calibration methods, thereby enhancing the systems of ionizing radiation dosimetry. The relevance of such projects is driven by the widespread use of ionizing radiation in medicine and industry. In medicine, particularly in radiotherapy, accurate dosimetry ensures effective treatment with minimal impact on healthy tissues. In industrial radiography, high-precision dosimetry guarantees compliance with safety standards, reducing the risk of excessive exposure to the radiation for workers. Within the framework of this international project, involving the Physikalisch-Technische Bundesanstalt (PTB) and the Central Office of Measures (GUM), new calibration protocols for various types of radiation are being developed, traceability chains to ensure measurement accuracy are being established, and best practices are being shared among participants. To achieve these objectives, preliminary comparisons were conducted among NMIs, with two Institutes acting as reference laboratories. This approach allowed the participants to compare their results with control data and make all necessary adjustments. Such collaboration has fostered knowledge exchange and stimulated the development of new dosimetry techniques, which, in the long term, will enhance the precision and reliability of measurements. The NSC “Institute of Metrology” participated in the project as Ukraine’s leading institution in the field of ionizing radiation. The results of this collaboration are presented in the paper, specifically focusing on comparisons of ionizing radiation using the 137Cs and 60Co sources. Additionally, within the framework of the project, the comparisons of X-ray beams with radiation qualities N-40, N-100, and N-200 were conducted.