Loading characteristics of an electrostatic coaxial lens

The position of the image is calculated as a function of the position of the object (tubular beam) for an electrostatic system consisting of two coaxial cylinders and an end diaphragm with an annular slit. Zh. Tekh. Fiz. 69, 123–126 (June 1999)     

Electron-optical characteristics of a combined electrostatic lens

The load characteristics of an electrostatic lens consisting of three coaxial cylinders are calculated. The lens is capable of focusing to one point both paraxial annular beams and annular beams away from the axis. In addition, it increases the intensity of a charged particle beam by roughly an order of magnitude compared with a commonly used single axisymmetric lens.     

A three-element cylindrical electrostatic lens for a photoelectron spectrometer

The properties of a three-element electrostatic lens for use in photoelectron spectroscope is reported. The lens, which keeps a constant focal position over a wide range of photoelectron kinetic energies, is coupled to a high resolution hemispherical electrostatic analyzer. Maximum utilization of the electron optics is described.     

Influence of the edge field on the focusing properties of a coaxial cylindrical lens

The effect of the distance between the grounded flat entrance diaphragm and the outer cylindrical electrode (which determines the edge field of the lens) is investigated over a wide range of variation of the geometry of a coaxial cylindrical lens. It is found that focusing of a charged particle beam on the lens axis is achieved over a wide range only in the case of small clearances between the diaphragm and the outer electrode. It is shown that for an alternative power feed arrangement, in which the outer cylindrical electrode is grounded and the voltage is applied to the inner electrode, beam focusing is in general degraded, in particular on the lens axis. Zh. Tekh. Fiz. 68, 124–127 (June 1998)     

A thin lens formula of the electrostatic bi-potential lenses

A thin lens formula, whose object and image planes are measured from the lens center, is derived for electrostatic bi-potential lenses. Its approximation degree is discussed.     

A lens formula for an electrostatic lens accompaning pre- and after electric fields

The virtual object and image are introduced in order to apply the usual lens formula to an electrostatic lense accompaning pre- and/or electric fields. In case of the uniform electric field, their positions are simply expressed as a function of the accelerating or decelerating potential ratio.     

Studies of the characteristic parameters for a flattened-Gaussian beam through a defocusing lens

By introducing an equivalent focal length, analytical propagation equations of the characteristic parameters for a flattened-Gaussian beam through a defocusing lens in free space are obtained on the basis of Collins diffraction formula and definition of high-order intensity moments. The parametric characteristics of beam width, kurtosis parameter and power in the bucket are analyzed and discussed analytically or numerically. Numerical results show that the effects of different kinds or values of defocusing coefficient of the lens on these parameters are different. It is concluded that the action of the lens with different defocusing coefficient can be compensated by a series of lenses with different focal length in theory.     

Computer simulations for intense continuous beam transport in electrostatic lens systems

A code LEADS based on the Lie algebraic analysis for the continuous beam dynamics with space charge effect in beam transport has been developed.The program is used for the simulations of axial-symmetric and unsymmetricalintense continuous beam in the channels including drift spaces.electrostatic lenses and DC electrostatic accelerating tubes.In order to get the accuracy required,all elements are divided into many small segments,and the electric field in the segments is regarded as uniform field,and the dividing points are treated as thin lenses.Iteration procedures are adopted in the program to obtain self-consistent solutions.The code can be used in the designs of low energy beam transport systems,electrostatic accelerators and ion implantation machines.     

An electrostatic interpretation of some empirical parameters of light quarks

Values of some arbitrary parameters appearing in a geometrical model for elementary particles developed by MacGregor are compared with quantities associated with classical properties of blocks of charges±e interacting via Coulomb forces and hard-sphere repulsion only. If it is assumed that masses and radii of individual charged particles are related bymc ²=(2/3)(e ²/r) and thatmc ²=6.87 MeV, then the self-energiesM andM ^± of 24-particle neutral blocks and 25-particle charged blocks composed of layers of three octagons and of a square sandwiched by two distorted octagons satisfyM=70.1 MeV,M ^±=74.2 MeV. The binding energyB _nn of pairs of neutral blocks is given byB _nn=4.9 MeV, and the maximum radius of the neutral block is 0.60 F. These four calculated parameter values lie within an average of 1% of the corresponding quantities for nonspinning quarks determined empirically by MacGregor.     

Radial focusing of ion beams in a mass analyzer with an electrostatic lens and a sector-shaped inclined-wall magnetic prism

The ionic and optical properties of an inclined-wall magnetic mass analyzer with electrostatic direction focusing of ions in a nonuniform (r ^?1) magnetic field were studied. A condition for ion focusing in the radial plane was derived, and the basic parameters of the mass analyzer were determined.     

Excilamp with a coaxial feedline

We describe a mathematical model of electrophysical processes occurring in the system consisting of a transistor inverter, an oscillatory circuit, a step-up transformer, a long feedline, and a barrier-discharge lamp. We propose and test a method for effective transmission of a high-frequency voltage from a power supply to the barrier-discharge lamp via a long coaxial line in which the voltage was applied to the electrodes of the lamp in the form of harmonic voltage bursts at a frequency close to the self-resonant frequency of the excitation system.     

Precision magnetic quadrupole lens for a nuclear scanning microprobe based on an ÉGP-10 electrostatic tandem accelerator

Basic ideas underlying the design of a precision magnetic quadrupole lens for a nuclear scanning microprobe with a maximal accelerating voltage of 14 MV are set forth. Four magnetic quadrupoles are combined into doublets. The doublets are placed on adjusting gears, which bring the local coordinate system of each lens into coincidence with the laboratory system related to the axis of the beam. Each lens provides a maximal gradient of the field of 0.68 T/cm, which makes it possible to perform stigmatic focusing of the beam with a working distance of 22 cm. All lenses are nonseparable and made of one piece of high-quality electrical steel. A special lens-feeding unit is designed that provides manual and remote control of pole tip excitation.     

Interferometric specification of lens (single and doublet) parameters

Three-dimensional analysis of intensity distribution in the interference field of two interfering waves enables one to reconstruct the corresponding wave vectors at each point in space. This has been exploited to specify the radii of curvature, the refractive indices and the thicknesses of a single lens and components of a doublet. The introduced technique is very suitable for lenses of small diameters and short focal lengths.     

电机补偿式焦度仪镜片参数的计算

针对目前市场上测量眼镜片相关参数全自动焦度仪测量范围小、测量精度较差等问题,研制了基于电机补偿原理的焦度仪。该焦度仪采用步进电机带动分划板做线性运动对分划板的位置进行补偿,通过改变焦度仪光学系统的物像关系来提高焦度仪的测量精度,扩大它的测量范围。测量时放入待测镜片,待整个调节过程结束后,电器部件会将每个接收到的图像进行分析计算后取平均值,得到待测镜片的各项参数。利用本样机对一些典型镜片进行了测量,结果显示所有镜片的误差范围均在±0.02 m-1内,表明本文研制的焦度仪完全符合国家计量检定规程的计量检定要求。     

电机补偿式焦度仪镜片参数的计算

针对目前市场上测量眼镜片相关参数全自动焦度仪测量范围小、测量精度较差等问题,研制了基于电机补偿原理的焦度仪。该焦度仪采用步进电机带动分划板做线性运动对分划板的位置进行补偿,通过改变焦度仪光学系统的物像关系来提高焦度仪的测量精度,扩大它的测量范围。测量时放入待测镜片,待整个调节过程结束后,电器部件会将每个接收到的图像进行分析计算后取平均值,得到待测镜片的各项参数。利用本样机对一些典型镜片进行了测量,结果显示所有镜片的误差范围均在±0.02 m-1内,表明本文研制的焦度仪完全符合国家计量检定规程的计量检定要求。     

慢波结构参数对同轴相对论返波管线性增长率的影响

 根据线性理论推导同轴相对论返波管色散方程和线性增长率,分别给出了波纹深度和波纹周期改变对于同轴相对论返波管线性增长率的影响规律,发现在一定范围内,减小波纹周期或者增大波纹深度能够降低结构波相速度,获得较大的线性增长率。     

Capacitance of a coaxial line terminated by a gap

Capacitance of a coaxial line terminated by a gap is investigated. An electrostatic boundary-value problem of the coaxial line terminated by a gap is rigorously solved based on the Fourier sine transform, mode matching technique, and superposition. The capacitance of the coaxial line is represented in a fast-convergent series and computed in terms of the gap geometry and the gap permittivity.