两电极静电同心球系统的近轴电子光学及其空间-时间像差

将从近轴解出发研究两电极静电同心球系统的空-时轨迹及其像差.由近轴轨迹方程和近轴运动方程出发,先求解两电极静电同心球系统中自光阴极逸出的运动电子的近轴空间-时间轨迹,然后讨论此系统的静动态电子光学及其空间-时间像差,揭示近轴光学系统成像的一般规律.文中定义和推导了各级近轴空间像差和近轴时间像差,得到了与关于近轴空间-时间像差同样的结论,表明完全可以直接由近轴轨迹方程和近轴运动方程出发来研究理想成像及其空间-时间像差.     

两电极静电同心球系统的成像电子光学及其空间-时间像差

基于实际轨迹方程和电子运动方程对两电极静电同心球系统求解由光阴极逸出的运动电子的空间和时间轨迹,推导成像位置和电子飞行时间的精确和近似表达式,并由空间和时间轨迹的解析解出发讨论系统的空间-时间特性.对空间像差和时间像差给出统一的定义,即横向像差可视为近轴横向像差和几何横向像差的合成,时间像差可视为近轴时间像差和几何时间像差的合成,并导出了所有相应的像差表示式.     

Paraxial imaging electron optics and its spatial-temporal aberrations for a bi-electrode concentric spherical system with electrostatic focusing

The paraxial solutions play an important role in studying electron optical imaging system and its spatial-temporal aberrations, as was discussed in previous paper [1], but investigation of a bi-electrode concentric spherical system with electrostatic focusing directly from paraxial electron ray equation and paraxial electron motion equation has not been done before. In this paper, we shall use the paraxial equations to study the spatial-temporal trajectories and their aberrations for a bi-electrode concentric spherical system with electrostatic focusing.In the present paper, start from the paraxial ray equation and paraxial motion equation, the paraxial spatial-temporal trajectory of moving electron emitted from the photocathode has been solved for a bi-electrode concentric spherical system with electrostatic focusing. The paraxial static and dynamic electron optics, as well as the paraxial spatial-temporal aberrations in this system are then discussed, the general regularity of imaging in paraxial optical system has been explored. The paraxial spatial aberrations, as well as the paraxial temporal aberrations with different orders, have been defined and deduced, that are classified by the order of (?_z/?_ac)^1/2 and (?_T/?_ac)^1/2. Thus we get same conclusions about paraxial spatial and temporal aberrations as we have given in the previous paper and it completely shows that the paraxial spatial-temporal aberrations can be investigated directly from the paraxial ray equation and paraxial motion equation.     

Theory of paraxial lateral aberrations of electrostatic imaging electrostatic electron optics based on asymptotic solutions and its verification

In imaging electron optics, study of geometrical lateral aberrations of third order and paraxial lateral aberrations of second order has traditionally been paid more attention to, but the existence of paraxial chromatic aberrations of third order and paraxial chromatic aberrations of magnification of third order was almost ignored, and the general form of paraxial lateral aberration has not been studied theoretically.In the present paper, the paraxial lateral aberrations expressed in general form have been derived emphatically on the basis of asymptotic solutions of paraxial equation. The relationship between the coefficients of asymptotic solutions has been investigated, which proves that the coefficients of asymptotic solutions are related each other. Through a bi-electrode electrostatic spherical concentric system model, two special solutions expressed by asymptotic solutions and accurate solutions in a bi-electrode electrostatic spherical concentric system have been deduced, and the paraxial lateral aberrations have been verified and tested, in which the aberration coefficients are solved by asymptotic solutions of paraxial equation. Result completely proves that the approach based on asymptotic solutions to solve the paraxial lateral aberrations are practicable and accurate enough. The paraxial chromatic aberration of magnification of third order and the paraxial chromatic aberration of third order have been firstly derived, and the Recknagel-Artimovich formula of paraxial chromatic aberration of second order which possess an greatest part in the whole paraxial lateral aberrations has been deduced and confirmed. A simple and clear form for expressing paraxial lateral aberrations of imaging electron optics is suggested for practical use. Results of the present paper will have theoretical value for aberration theory of imaging electron optics and practical significance for the design of image tubes.     

静电聚焦同心球系统验证电子光学成像系统的时间像差理论

关于动态电子光学成像系统的时间像差理论,计算时间像差系数有两种方法——τ变分法和直接积分法.它们的差别在于：τ变分法计算二级几何时间像差系数必须求解微分方程,而直接积分法仅需进行积分运算.采用静电同心球系统的理想模型对这两种方法的正确 性进行了检验.结果表明：这两种方法求解电子光学成像系统的时间像差系数的结果完全一致,所求得的时间色差系数与理想模型的解析解完全相同,从而证明两种方法是等价并且正确的.通过验证表明,直接积分法的计算更为简便,适于实际系统的计算与设计. 关键词： 阴极透镜 电子光学成像系统 动态电子光学 时间像差理论     

Wiggler聚焦带状注速调管电子光学系统的设计

带状注速调管可以在高频段实现高功率微波输出,电子光学系统是带状注速调管的关键部件。阐述了Wiggler双平面聚焦理论,设计了新型椭圆形柱面阴极和椭圆形聚焦极结构,阴极曲率半径为17 mm,长轴10 mm,短轴4 mm;聚焦极长轴28.8 mm,短轴10.4 mm。采用这种结构可以直接产生椭圆形带状电子注,且阴极发射电流密度较为均匀。设计了周期长度为8 mm,总长度为108 mm,中间带有凹槽并可以实现双平面聚焦的Wiggler结构,模拟显示电子注填充因子在75%左右,通过率达到100%。设计了新型的菱形收集极结构,电子轨迹在收集极内发散均匀。     

Bunching mechanism and kinetic analysis of the relativistic electron beam in centrifugal electrostatic focusing system

This paper proposes an azimuthal bunching-mechanism of a relativistic electron beam with circular orbits in the centrifugal electrostatic focusing system (CEFS). A kinetic theory is given which is in principal agreement with the proposed bunching-mechanism. A new proposal is presented that the electron beam is obliquely injected into CEFS.