Abstract：According to the relationship between the photon flux, fluence and air kerma of X-ray beam, the required photon flux and fluence were determined through the measurement of air kerma. It is based on the principle of X-ray free-air ionization chamber, and aiming at the physical conditions of synchrotron radiation photon beam, the scheme and design of free-air chamber were determined and the precise processing and adjustment were completed. The dimensional tolerance, mechanical properties and electrical properties of the main parts of the ionization chamber meet the requirements of metrological standards. It provided a basis for the establishment of metrological standards. The main parts size and tolerance as well as mechanical and electrical properties, to meet the requirements of metrological standards. It provides the foundation for the establishment of metrological standard.
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2020, Vol. 41 
