电磁聚焦移象系统中静电聚焦场的逆设计

本文对电磁聚焦移象系统中静电聚焦场的逆设计进行了研究,利用多电极系统静电场的电位迭加原理,建立了数学模型,用最优化方法对系统的静电聚焦场进行了设计计算。     

Hollow-beam focusing with electrostatic and periodic magnetic fields

A new method of focusing a hollow cylindrical electron beam is presented. The focusing system consists of a cylindrical center conductor inside the beam, a cylindrical outer conductor enclosing the beam, and a series of periodic magnets outside the tube. A radial electrostatic field between the conductors provides an outward force on the electrons. The periodic magnetic field produces an inward force on the electrons. The inward and outward forces can be adjusted to provide a balance of all the forces acting on the electrons at both boundaries of the beam by choosing the electric and magnetic fields properly. An approximate analysis has been made and is presented which gives necessary design information. A number of curves are presented which are useful in designing focusing systems of this type. Experimental results on a beam tester show that current transmission of over 90 per cent for perveance up to 11 micropervs can be obtained readily. The adjustments are not critical and the performance is very stable.     

缩小倍率型永磁聚焦天文成像探测器系统的研究

本文从当代天文光电成像探测器的发展现状与实际需要出发，着重探讨寻求允许输入像面不是平面、放大倍率不等于１的永磁聚焦磁场系统的设计途径，用约束变尺度法来设计在电磁聚焦成像系统中实现给定的不均匀磁场分布的实际永磁环磁路系统。     

Gyro-peniotron focused by radial electrostatic field and axial magnetostatic field

This paper proposes a new gyro-peniotron with large-orbit relativistic E-beam in a coaxial waveguide, where the E-beam is focused by both radial electrostatic field and axial magnetostatic field. A linear theory of a 3-D model is presented to describe the device. Numerical analysis is carried out. It is found that a proper proportion of the radial and axial focusing fields makes the growth rate greater, and the electron's axial displacement as well as the axial perturbation forces should be taken into account unless the E-beam is focused only by axial magneto static field. As a special example, a centrifugal electrostatic focusing gyro-peniotron is also discussed.     

Electron trajectories in twisted electrostatic deflection yokes

A mathematical analysis is carried out for electron motion in a cylindrical electrostatic deflection yoke which is twisted around its axis and immersed in a uniform axial magnetic field to form a twisted focus projection and scanning (FPS) deflection system. The yoke has an arbitrary twist angle, and is a generalization of yokes with π/2 rad of twist recently used in FPS vidicons. New modes of operation are found which eliminate shading caused by off-normal beam landing at the target, while providing improved deflection sensitivity, increased resolution, and reduced power consumption in the focusing solenoid as compared with the untrusted shading-free mode previously reported by Schlesinger, Wagner, and Saldi [1]-[3]. The theoretical predictions are supported by data from experimental devices.     

Analysis on electrostatic pattern yoke camera tubes

To investigate the features of electron-beam systems in electrostatic deflecting camera tubes, a method for calculating the deflection field of the twisted curved-arrow pattern yoke is presented using the method of separation of variables. In spite of three-dimensional analysis, field values at 2000 points can be calculated at 10^-3accuracy within 1 min using a HITAC-M200H computer. Distributions of deflection field also are given. Furthermore, deflection aberrations of electron beams are analyzed in the magnetic focusing and electrostatic deflecting (MS) systems. It is revealed that the favorable features of MS beam systems can be realized only by utilizing a nonuniform magnetic field. It is also seen that deflection aberrations and landing error are very dependent on a twist in the pattern yoke.     

The fabrication and application of Zernike electrostatic phase plate

The Zernike electrostatic phase plate (ZEPP) consisting of three ring electrodes and two insulating rings has been fabricated using Micro Electro-Mechanical System processes. The electrostatic field produced in the phase plate was measured by electrostatic force microscopy. The electrostatic field and focal length of the phase plate is calculated using electron optics principles. The comparison of the experimental electrostatic field and the theoretical calculated is discussed. Finally, we report the application of ZEPP to enhance contrast of the SiON(x)/SiO(2) interface in an NMOS semiconductor device. The quantitative analysis of the contrast enhancement versus the applied bias is discussed in detail.     

基于物理农业的数控高压静电场电源设计

高压静电场可以激化种子内部活力,在物理农业中已得到广泛应用。为此,设计了一种数控高压静电场电源,该电源通过单片机编程进行零点检测和占空比调整,控制晶闸管触发,为高压产生电路提供0～200V直流电压。同时,通过编程产生方波,作为激励脉冲信号,使高压电路产生0～55kV的高压静电。经实验测试,该高压静电场电源能够满足不同种子的高压静电场需求。     

Theory of periodic electrostatic focusing of electron beams

A general theory of periodic electrostatic focusing structures in micowave tubes is presented. A general method for evaluating the properties of focusing systems is developed. The method is based on the use of the Action Function and is applicable to structures whose potential distribution can be found by the method of separable variables. It is shown that this approach can yield results similar to, but more exact, than those obtained by the classical paraxial ray equation. The basic and double-ring structures have been examined in detail. Parameters describing these structures are presented in graphical and tabular form. It is shown that for irrotational flow, a specific current distribution is required. The use of computer techniques for the solution of electron flow problems is discussed. A computer analysis has been developed and results obtained are discussed. The accuracy of the Action Function and the computer analyses has been verified experimentally. It has been shown that the focusing potentials predicted by the Action Function analysis are in good agreement with the experimental values. The computer analysis has also been shown to give results comparable with those obtained practically. Hollow beams of 3.85, 5.4, and 15.6 µP have been focused using the basic ring structure. In order to investigate the effect of unbalance of focusing and defocusing forces at the inner beam boundary, pinhole measurements have been made. It is shown that the ring structure focuses a hollow beam with some change in the beam cross section. The effect of the unbalance of forces is to transform the current density profile. Results indicate that the transformation is desirable since a beam of constant current density may be transformed to a distribution which approaches that required for irrotational flow.     

基于电场操控面形的非球面复合透镜制作

介绍了一种制作非球面复合透镜的新方法.根据电场作用改变液滴透镜面形的原理,利用SU-8光固胶直接在双凹透镜表面制作液滴复合透镜,以电场作用操控液滴复合透镜的面形得到非球面,并实时检测其面形和焦斑图像,在检测到较好的透镜面形和聚焦状态时,用紫外光固化得到低像差的非球面复合透镜.研制了基于电场操控面形的非球面复合透镜制作实验平台,实验检测并讨论了复合透镜在电场中的变形,计算了其主曲率和焦距的变化规律.与原有的平凸非球面液滴透镜相比,此透镜具有更长的焦距和更大的变焦范围,并能保持低像差,改进了基于电场操控面形的非球面透镜制作技术,拓宽了非球面液滴透镜的应用范围.     

THEORETICAL ANALYSIS FOR THE RELATIVISTIC ELECTRON BEAM IN A CENTRIFUGAL ELECTROSTATIC FOCUSING SYSTEM

A fundamental analysis of negative-mass instability in the interaction between a relativisticelectron beam and TE mode in a centrifugal electrostatic focusing system is given.A kinetic theory ispresented and corresponding discussion on practical application is carried out.     

A further contribution to the theory of electrostatic focusing

An attempt has been made to obtain an accurate analytical solution to the equation of motion of an electron in a periodic electrostatic field. It has been shown that the equation is of the inhomogeneous Mathieu type. The general solution has been obtained and the effect of various parameters is discussed. It is hoped that this solution will find applications in many problems of particle dynamics.     

Determination of electrostatic fields and equipotentials using Fredholm's method

The electrostatic field and potential induced by an electrical charge inside a conductive cavity are calculated. First, the density of charge induced on the internal surfaces of the cavity has to be determined. This density is related to the original charge by an integral equation. Then, by the use of Fredholm's method this integral equation is reduced to a conventional system of algebraic linear equations, yielding density values at definite points of the internal surfaces, and hence electrostatic field and potential values at any internal point of the cavity. Fredholm's method is well suited to cavities with internally intricated structure and avoids numerical convergence difficulties.     

静电喷印技术在太赫兹超表面制备中的应用

近年来,太赫兹技术快速发展,基于超表面的太赫兹器件受到广泛关注,并已应用于太赫兹成像、光谱和生物传感等诸多领域。但太赫兹超表面器件的制备复杂且成本高,而静电喷印技术无需掩模版,成本低、精度高且易于在异形曲面上制作。基于静电喷印技术设计和制备了太赫兹吸波器,并利用太赫兹时域光谱系统（THz-TDS）对样品进行了性能测试,实验与仿真结果基本相符,在0.098~0.353 THz频段内吸收大于90%。此外,还设计了太赫兹线极化转换器,在0.167~0.355 THz频段内的极化转换大于95%,相对带宽约72%,并分析了所设计样品的制备工艺条件,验证了静电喷印技术对于制备太赫兹极化转换器的可行性。研究成果表明,静电喷印技术在太赫兹超表面器件的制备中具有广泛的应用前景。     

计算像管三维静电场的多重网格法

研究了利用多重网格法计算静电像管的三维静电场分布。通过计算同心球系统与倾斜的双圆筒阴极透镜两个例子,表明计算精度可以达到10-3～10-4。通过比较多重网格法与有限差分法计算三维静电场的计算精度和计算效率,发现多重网格法的收敛率为常数。在相同计算精度的情况下,其计算效率比有限差分法快8～31倍,有效地提高了求解三维静电场的计算效率,从而为非旋转对称静电像管的设计打下了坚实的基础。     

System integration of high voltage electrostatic MEMS actuators

A system integration for High Voltage (HV) electrostatic MicroElectroMechanical Systems (MEMS) actuators is introduced on a micro-Printed Circuit Board. The system includes a programmable microcontroller, a programmable DC/DC converter, a multi output HV interface and electrostatic MEMS actuators. The system produces high output voltages (10–300 V) and can control a large variety of MEMS capacitive loads (1 to 50 pF) by combining diverse semiconductor technologies. This system proves that technologies, such as low voltage CMOS of different processes, high voltage DMOS and MEMS, can interact, communicate and even be integrated as a System In Package (SIP), providing significant size and cost reductions. The system was programmed to control electrostatic MEMS actuator. The DC/DC converter was made from components of different technologies and two addressable high voltage CMOS interfaces were fabricated with DALSA's 0.8 μm High Voltage process. A prototype of the global system has been built and tested.     

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.     

The charge-density method of solving electrostatic field: Program and error analysis

The Charge-Density method of solving electrostatic field has many advantages over the finite difference or finite element method, but its accuracy and fitness are still in question. By direct evaluating electrical potentials, the errors along surface of the electrode are plotted, which are the maximum errors for an electrostatic problem. It is shown that higher accuracy will be reached if more sub-regions are chosen at where the charge density is high or at the region near the area where the field is to be calculated. This will be helpful to understand and use the method efficiently. It is more convenient and accurate to use the chargedensity method when we deal with the calculation of an electrostatic system having a great difference in size between electrodes (such as the point emitter diode). Using the information of error on the surface of electrode, we can estimate the potential errors in each calculation or rearrange the sub-regions to improve the accuracy of the next calculation. A program is set up. The difference between the calculated data and that of E. Harting and F. H. Read (1976) is less than 1%.     

Understanding the failure mechanisms of microwave bipolar transistors caused by electrostatic discharge

Electrostatic discharge(ESD) phenomena involve both electrical and thermal effects,and a direct electrostatic discharge to an electronic device is one of the most severe threats to component reliability.Therefore, the electrical and thermal stability of multifinger microwave bipolar transistors(BJTs) under ESD conditions has been investigated theoretically and experimentally.100 samples have been tested for multiple pulses until a failure occurred.Meanwhile,the distributions of electric field,current density and lattice temperature have also been analyzed by use of the two-dimensional device simulation tool Medici.There is a good agreement between the simulated results and failure analysis.In the case of a thermal couple,the avalanche current distribution in the fingers is in general spatially unstable and results in the formation of current crowding effects and crystal defects.The experimental results indicate that a collector-base junction is more sensitive to ESD than an emitter-base junction based on the special device structure.When the ESD level increased to 1.3 kV,the collector-base junction has been burnt out first.The analysis has also demonstrated that ESD failures occur generally by upsetting the breakdown voltage of the dielectric or overheating of the aluminum-silicon eutectic.In addition,fatigue phenomena are observed during ESD testing,with devices that still function after repeated low-intensity ESDs but whose performances have been severely degraded.