| More recently,the use of electron linear accelerator has been extended to industry,agriculture,food safety,military field and so on,where it is desirable to realize the miniaturization and mobility of LINAC to advance all these applications The traditional remnant power absorbing load much limits the miniaturization due to its complex and loose structure.Based on the application of the high efficient absorbing material FeSiAl in this subject,we study and explore the design of the compact absorbing load to satisfy the need of developmentThere are two ways in the realization of the compact absorbing load.The first is to substitute the output coupler and remnant power absorbing load by the collinear load.The second is to shorten the length of the waveguide load by the application of high-efficiency microwave absorbing materials.This dissertation is devoted to the design research of these two kinds of absorbing loads by combining theoretical analysis with experimental test on the foundation of study of predecessors.S-band collinear load is applied to the practical project with good effects.A feasible method to measure the complex electromagnetic parameters of the new absorbing material FeSiAl coating is provided.Then,a compact S-band waveguide load about 230mm in length is designed.The study involves the interdisciplinary field of electromagnetics,accelerator physics and technology,heat transfer and so on.Multi-physics coupling simulation is adoptedIn order to study the application of FeSiAl alloy and meet the needs of the subject,a 4-cavities collinear load to absorb 4kW remnant power is designed.A design strategy of simulation combined experiment is proposed.A precise displacement worktable is adopted to guarantee high-precision measurement of microwave parameters and an optimized length of the probe is obtained.By linear-fitting the electromagnetic parameters of FeSiAl with the measured data,the electromagnetic parameters are corrected.Finally,the collinear cavities are modified to the desired performance with the help of a matched RF input coupler.Actual running in a LIN AC of 14MeV also shows that the collinear load works well.Measuring the microwave attenuation of the waveguide structure to measure the complex electromagnetic parameters of absorbing materials FeSiAl is successful.The waveguide structure is with a short circuit plate sintered FeSiAl inclined to the rectangular waveguide and the microwave absorbing material FeSiAl is in form of coated thin layer with sandwich structure.The relationship between the attenuation of the structure and the complex permittivity and permeability of the coating material is established to be matrix and the coefficient matrix is fitted by training with the help of CST Microwave Studio.The fitting process is perfected with the application of the relation matrix rebuilt according to the theory of the hyperplane.Finally,the complex electromagnetic parameters of the FeSiAl coating are determined and the method is validated its reliability highly consistentBased on the measurement results of electromagnetic parameters of the FeSiAl coating,the influence of coating volume and load structure on the attenuation performance of different waveguide load is simulated.The compact S-band waveguide load was designed.The results show that the coating performance of the coating can be improved by analyzing the coating performance of the coating.Finally,according to the multi-physics coupling simulation,the thermal characteristics of the waveguide load structure are studied,and the cooling system with the S-wave waveguide dry load is designed. |
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