X射线源是X射线显微成像系统的核心部件,其功率密度和焦斑大小与聚焦系统密切相关。本文对高功率密度微焦斑X射线源的聚焦系统进行了优化设计,包括透镜结构设计、多透镜工作模式的选择、透镜间距优化等。本文设计了小球差系数的物镜;提...X射线源是X射线显微成像系统的核心部件,其功率密度和焦斑大小与聚焦系统密切相关。本文对高功率密度微焦斑X射线源的聚焦系统进行了优化设计,包括透镜结构设计、多透镜工作模式的选择、透镜间距优化等。本文设计了小球差系数的物镜;提出了由聚光镜、辅助聚光镜和物镜组成的多透镜聚焦系统,以实现系统较大的缩放比率和束流较高的传递效率;优化了透镜间距,以保证在满足系统缩放比率的前提下减小聚光镜的安匝数。最后,运用MEBS公司专业电子束计算软件,计算仿真了160 k V的加速电压下聚焦系统中透镜的场分布、电子的运动轨迹、像差、束斑分布等电子光学参量,最终得到束流为80μA,束斑为0. 9μm,功率密度优于1 W/μm^2的微束斑电子束。本文设计的聚焦系统为高功率密度微焦斑X射线源的设计和研制提供了依据。展开更多
By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the pr...By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the practical model.It is pointed out that the end ear and the distribution of the fieldparameter B<sub>0</sub>（z）have important effects on the deflection aberrations.An example is given,in which the elec-tron optical properties of the deflection coils having cosine distribution and finite length and that of the de-flection coils having distributed winding are compared.展开更多
In this paper, a general theory of the relativistic asymptotic third order geometrical and first order chromatic aberrations of a combined electrostatic-magnetostatic focuslng-deflection system have been presented. Al...In this paper, a general theory of the relativistic asymptotic third order geometrical and first order chromatic aberrations of a combined electrostatic-magnetostatic focuslng-deflection system have been presented. All their aberration coefficients contain no derivative higher than the second order. The divergence in Hawkes’ theory of asymptotic aberrations has been thoroughly voided in the present paper.展开更多
The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandw...The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.展开更多
文摘电子光学系统是真空电子器件的重要组成部分,主要包括电子枪、聚焦系统和收集极.电子光学系统的电子注聚焦和传输特性对器件性能指标至关重要,直接影响器件的输出功率、增益和带宽等特性.本研究设计0. 5 THz返波管电子光学系统,详细阐述电子枪和均匀永磁聚焦磁场的设计过程.根据返波管高频结构PIC (particle-in-cell)热腔模拟计算结果,设计符合电流发射要求且束流品质良好的电子枪,并结合理论分析,设计与之匹配的均匀永磁聚焦磁场.该电子光学系统主要工作和尺寸参数为:工作电压为23 kV时,阴极发射电流大于100 m A,电子通道的长度和直径分别为26 mm和0. 2 mm.
文摘X射线源是X射线显微成像系统的核心部件,其功率密度和焦斑大小与聚焦系统密切相关。本文对高功率密度微焦斑X射线源的聚焦系统进行了优化设计,包括透镜结构设计、多透镜工作模式的选择、透镜间距优化等。本文设计了小球差系数的物镜;提出了由聚光镜、辅助聚光镜和物镜组成的多透镜聚焦系统,以实现系统较大的缩放比率和束流较高的传递效率;优化了透镜间距,以保证在满足系统缩放比率的前提下减小聚光镜的安匝数。最后,运用MEBS公司专业电子束计算软件,计算仿真了160 k V的加速电压下聚焦系统中透镜的场分布、电子的运动轨迹、像差、束斑分布等电子光学参量,最终得到束流为80μA,束斑为0. 9μm,功率密度优于1 W/μm^2的微束斑电子束。本文设计的聚焦系统为高功率密度微焦斑X射线源的设计和研制提供了依据。
文摘By using the expressions of the field parameters and with the aid of the Orthogonal DesignMethod,we optimized the design of the saddle delection yoke with a ferromagnetic shield.The results ob-tained agree with the practical model.It is pointed out that the end ear and the distribution of the fieldparameter B<sub>0</sub>（z）have important effects on the deflection aberrations.An example is given,in which the elec-tron optical properties of the deflection coils having cosine distribution and finite length and that of the de-flection coils having distributed winding are compared.
基金Project supported by the National Natural Science Foundation of China.
文摘In this paper, a general theory of the relativistic asymptotic third order geometrical and first order chromatic aberrations of a combined electrostatic-magnetostatic focuslng-deflection system have been presented. All their aberration coefficients contain no derivative higher than the second order. The divergence in Hawkes’ theory of asymptotic aberrations has been thoroughly voided in the present paper.
文摘The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.
