The Research For Correction Factor Of X-ray Free Air Ionization Chamber

Development today, the application of X-ray, already deep into the security check,medical diagnosis and radiation monitoring and detection of aeronautics and astronautics and other fields.At present, establish and perfect the country's social development, high and new technology and national defense construction for X ray measurement standard system;Improve and strengthen existing X-ray measurement standard of technology and innovation ability;Solve the key technical problems,international comparison is to participate in the international comparison to fill gaps in the X ray measurement research focus.Paper based on NIM in the basic scientific research business special in the X-ray protection level standard establishment and study of low energy X-ray benchmark device design and processing, set up in CCRI recommended low energy X-ray radiation quality specification to reference, under the radiation quality specification for low energy X-ray free air ionization chamber partially modifying factor measurement;Molybdenum target X-ray benchmark device, and use of molybdenum target X-ray free air ionization chamber partially modifying factor were measured;Also use EGSnrc and EGS5 monte carlo simulation software on the part of the correction factor of the two free air ionization chamber is simulated calculation;At the same time, developed a set of low energy X-ray freedom of molybdenum target X-ray air ionization chamber and air ionization chamber air attenuation correction factor used in the vacuum tube measurement system.The thesis first of all, both at home and abroad at present for X-ray free air ionization chamber correction factor in full introduction of the study.Independent design and build a set of benchmark low energy X-ray device, the radiation beam,laser positioning, guide coaxial condition, study on the radiation field uniformity measurement, and through the combination of experiment and computer simulation method to calculate the correction factor under X-ray radiation quality specification,the correction factor is free air ionization chamber with other countries, compared to the value of the deviation within 13%?4%?4%?1% and 0.8%, compared to the value of the deviation within 1%?2%?1% and 1%.Designing a set of vacuum measurement system, using the principle of air attenuation, the low energy X-ray free air ionizationchamber and molybdenum target X-ray free air ionization chamber air attenuation correction.In the paper by using the method of monte carlo simulation, through the EGSnrc and EGS5 simulation software for low energy X-ray free air ionization chamber and molybdenum target X-ray free air ionization chamber electronic fluorescent loss and scattering correction factor was calculated.Paper design a set of independent research and development in the vacuum tube measurement system, completed the physical design of the whole system, mechanical structure design and processing and assembling.Completed the whole system under the condition of different pressure of X-ray, the system pressure measurement and the stability of the system measurement.The completion of the above research work, to a certain extent, established the X-ray free air ionization chamber correction factor of related research, laid a solid foundation for further research work, provides the emersion X-ray air kerma technical support, the international comparison of the value of X ray specification and the domestic various applications in the field of dissemination.