磁透镜与偏转器的复合系统的电子光学性质和象差理论

本文研究了旋转对称磁透镜和磁偏转器的复合系统,给出了场和轨迹的普遍表达式。利用向量形式来描写电子轨迹,讨论了高斯光学性质。运用变分原理(费马原理)计算了三级象差,得出了复合系统普遍的象差公式。它们以矩阵的形式表出,形式简洁,便于进行数值计算。本文的结果具有较大的普遍性,概括了文献上关于偏转象差的已有结果,并对复合系统作了较完整的论述和严格的计算,因而可以广泛地研究各种电子束管和电子光学仪器的偏转象差。     

宽束和细束电磁复合聚焦球面阴极透镜的象差理论

本文研究了对宽束和细束阴极透镜普遍适用的电磁复合聚焦球面阴极透镜的象差理论。在考虑物场和象场弯曲以及阴极面上磁场和横向电场不为零的情况下,导出了任意理想象面上的一级近轴横向象差和包括色象差在内的全部三级横向象差矩阵公式。所得的结果较为完整、普遍。本文详细讨论了宽束和细束阴极透镜的关系,并用轨迹法和变分法严格证明了:当考虑阴极面逸出电子具有一定的初能量和初角度分布,并采用准规范化电位表示的近轴轨迹方程来讨论系统的理想成象时,宽束和细束两类阴极透镜从象差理论以至导出的三级横向象差、象差系数表示式都可以统一起来。本文采用矢量描写轨迹,运用矩阵表示象差,形式简洁,象差系数积分收敛,适合于计算机计算。 关键词：     

高斯轨迹参量的线性变换对于电子光学象差的影响

本文从比较普遍的观点出发,采用矢量形式描写高斯轨迹,运用矩阵形式表示象差,从而讨论了普遍的高斯轨迹参量线性变换下的电子光学系统的三级象差和象差系数及其偏微商。由此得到了电子光学广义的Fraunhofer条件(即消除各向同性和各向异性彗差的条件),证明了在此条件下,象散和场曲取极值或稳定值。利用上述的普遍公式和结果,讨论了固定束和扫描束电子光学系统中光阑位置变化的影响,还讨论了阴极发射系统中磁浸没的影响。 关键词：     

阴极透镜象差的变分理论

本文运用变分原理研究了电磁复合聚焦阴极透镜的象差理论,导出了在任意象平面中象差系数的普遍公式。它们可以用Glaser导出的象差系数的线性组合来表示。这就表明了宽束与细束电子光学系统的象差都可以用统一的变分方法处理,并建立了两者之间的联系,本文采用矢量形式描写阴极透镜的近轴轨迹,并采用矩阵形式描写象差。本文所得的象差系数较之文献上已有结果形式更为简洁且适用于计算机计算。本文考虑了阴极面上磁场和横向电场不为零的情况,因而所得结果较为普遍。 关键词：     

电磁复合聚焦—偏转球面阴极透镜的相对论象差理论

本文应用变分原理研究了电磁复合聚焦-偏转球面阴极透镜的相对论象差理论。在考虑阴极面逸出电子具有一定的初能量和初角度分布,物场和象场弯曲以及阴极面上磁场和横向电场不为零的情况下,导出了任意理想象面上的一级近轴横向象差和包括色球差在内的全部三级几何横向象差,以及各种特殊类型象差系数的明显表达式。本文导出的象差公式不仅普遍适用于宽束和细束阴极透镜,而且普遍适用于相对论或非相对论,阴极和屏为球面或平面时的各种情况。本文以复数描写轨迹,用矩阵表示象差,形式简洁,适合于计算机计算。 关键词：     

存在初级象差下电子和离子光学系统中刘维定理的应用

在电子和离子光学理论(特别是象差理论)中,广泛地应用了矩阵的运算方法。本文讨论了旋转对称电子光学系统与重叠场(环形电场与非均匀磁场的叠加)离子光学系统中存在初级象差下的变换矩阵,证明了这些变换矩阵的行列式数值恒为1.这个普遍结论是刘维定理的具体应用。这对于电子和离子光学象差理论及计算机辅助设计具有一定意义。 关键词：     

磁圆形透镜和磁六极透镜的复合系统的象差

近来磁六极透镜作为球差校正器引起了人们的注意。本文研究了磁圆形透镜和磁六极透镜的场分布叠加形成的复合系统的象差。我们在复数域中定义了内积,采用了复数的表象和微分算符,全面讨论了这种复合系统的高斯光学性质及二、三、四级象差,得出了各级象差所有的象差系数的公式。 关键词：     

象差原理

前言象差与光学系统性能的关系、象差与系统结构的关系以及象差之间的关系是研究象差的几个重要方面,一般也是从这个方面来描述象差的规律的。那末,象差总的规律应怎样描述呢? 总的规律之中必然存在一些基本的规律。对共轴系统而言,象差的基本变化规律概括起来有四个,我们叫做产生象差的四个基本原因。这些基本原因的相互作用的形成是产生象差的复合原因,其中又分为內因和外因。外因是光学系统的性能,内因是系统的结构参量,所     

关于电磁复合聚焦阴极透镜的象差理论

本文对电磁复合聚焦阴极透镜的象差理论进行评述与研究,着重分析西门纪业和Бонштедт两篇代表性的文章,详细推导了两文的象差方程和象差系数。研究表明,尽管两文的象差系数在形式上迥然不同,但实质上是完全一致的,是可以互相转化的。从而证明Бонштедт对西门纪业的批评是没有根据的。按照我们的研究,成象系统的象差应在某一轴向初电位ε_(x1)而非ε_x所对应的象面上进行考察,从而导出电磁复合聚焦阴极透镜包括一级象差与三级象差在内的全部横向象差表达式 关键词：     

共轴球面光学系统的热象差分析

本文系统分析了径向均匀温度场中,热对共轴球面光学系统的影响,得到了初级位置热象差与初级倍率热象差的一般表达式.在此基础上得到了均匀温度场中薄透镜系统的热象差表示式,该热象差表示可以用来指导无热象差光学系统的设计.最后根据上述分析,讨论了几种简单系统的热效应与无热象差设计途径.     

A different algebraic method for the fifth-order combined geometric-chromatic aberrations of practical magnetic electron lenses

In this paper, differential algebraic (DA) method is applied to fifth-order combined geometric-chromatic aberrations of practical magnetic electron lenses. The magnetic fields of magnetic electron lenses, which are computed by FEM or FDM method, are in the form of discrete arrays. Thus the developed new DA method is applicable to engineering design and programs were written for computing the fifth-order combined geometric-chromatic aberrations of practical magnetic electron lenses. An example is given. The combined geometric-chromatic aberrations up to fifth order are calculated. It is proved that the numerical results for the magnetic fields in the form of discrete arrays have good accuracy compared with the results computed by using the magnetic fields expressed in analytical form. The accuracy is limited only by the accuracy of the numerical computation of the fields and the arithmetic errors. Finally, a practical magnetic electron lens is analyzed and discussed as an example.     

Optical out-of-plane spin polarization and charge conductivities in spin-orbit-coupled systems in the presence of an in-plane magnetic field

Out-of-plane spin and charge responses to the terahertz field for a clean two-dimensional electron gas with a Rashba spin-orbit interaction in the presence of an in-plane magnetic field are studied. We show that the characteristic optical spectral behavior is remarkably different from that of the system in the absence of in-plane magnetic fields. It is found that the optical spin polarization normal to the plane is nonzero even for this clean system, in sharp contrast to the static case. Due to the combined effect of spin-orbit coupling and in-plane magnetic field, both diagonal and off-diagonal components of optical charge conductivity tensor are nonvanishing. It is indicated that one can control the spin polarization and the optical current by adjusting the optical frequency. In addition, the out-of-plane spin polarization and conductivities strongly rely on the direction of the external magnetic field. Nevertheless, they meet different angle-dependent relations. This dynamical out-of-plane spin polarization could be measured by the time-resolved Kerr rotation technique.     

Different algebraic method for computing the high-order aberrations of practical combined focusing-deflection systems

Differential algebraic (DA) method is an effective technique in computer numerical analysis. It implements conveniently differentiation up to arbitrary high order, based on the nonstandard analysis. Some complicated nonlinear dynamics problem including high-order aberrations of electron optical systems can be solved effectively by mapping properties of DA quantities. However, the existing study applying DA method to the practical system is limited to simple electron lenses. In this paper, the application of DA method is extended to practical combined focusing-deflection systems, and the aberrations up to fifth order are calculated. The electric and magnetic fields of the electron lenses and deflectors, which are computed by finite element method (FEM) or finite difference method (FDM), are in the form of discrete arrays. Local analytical expressions for electric and magnetic field quantities are constructed from these arrays for arbitrary place where electron is traced in DA computation. Thus the developed DA method is applicable for engineering design and computing problem. Based on the study of the expressions and the structure of the aberration coefficients for the fifth-order aberrations of the combined focusing-deflection system and the local analytic expression of the practical electromagnetic field, correlative computer software was developed, whose interface is convenient to calculate the high-order aberrations of the practical systems. The new DA method and software are tested with a uniform magnetic field deflection having an analytic solution. And the results show that the accuracy is sufficiently high, only limited by machine precision. Finally, as an example, a practical combined magnetic focusing and magnetic deflection system is analyzed and discussed.     

强流电子束产生和传输的数值模拟

本文采用SLAC-226程序计算了1.5MV强流电子束在二极管内的加速过程以及出阳极后的传输过程。高亮度二极管的设计是高效率自由电子激光的关键技术之一。本工作的目的就是通过1.5MV注入器的数值模拟,为寻找优化的二极管结构设计提供一种有效的数值方法。程序考虑了外加电磁场和电子束自身空间电荷和自生磁场效应。我们讨论了外加磁场的各种构形以及它们对束流品质的影响,计算结果与国外EBQ程序计算结果和实验结果进行了比较,证明本工作的结果是可靠的。SLAC-226程序可以为直线感应加速器的设计提供参考数据。