Abstract：The measurement uncertainty of absorbed dose to water, Dw, in medical electron beams exceeds 3%, which is difficult to meet the requirements of clinical treatment and verification regulation of medical electron accelerator radiation source. The research on measuring electron beam radiation dosimetry using water calorimetry was carried out by the National Institute of Metrology (NIM), which realized the direct measurement of the Dw, with a relative standard uncertainty of 0.35%. At the same time, the research on the homogenous traceability of medical electron beams have also been carried out. Five schemes for measuring the absorbed dose to water in electron beams have been summarized. The relative standard uncertainty includes the highest 3.7% and the lowest 1.4%. In order to facilitate the measurement of the Dw in clinical electron beams, some suggestions on the selection and calibration methods of ionization chambers were provided, and precautions for different calibration coefficients were emphasized.
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WANG Zhi-peng,WANG Kun,JIN Sun-jun,YANG Xiao-yuan,QI Ya-ping,HUANG Ji,LIU Fu-bin. Measurements of Absorbed Dose to Water in Medical Electron Beams and Discussion of Its Uncertainty. Acta Metrologica Sinica, 2023, 44(12): 1897-1903.
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