Ion bombardment affects the stability and lifetime of micro-tip field emission devices. In the Si field emission array (FEA), the atoms in the residual gas may collide with electrons and be ionized, so many ions could be produced. Due to the electrical field in the FEA device, the ions bombard on the Si tips. This paper analyzes the mechanism of ion bombardment on the Si tip. The process concerning ion generation and ion bombardment is numerically simulated. The damage to the tip is analyzed quantitatively, and related conclusions are given.

It studies the optimization of charged particle optical system and proposes to separate the optimization of aberration from the optimzation of field in lens. In the optimization of aberration, the implication constraints are considered. In this optimization, it needs to do some simple integral calculations so that the calculation of field which will takes a lot of time is avoided. In the optimization of filed in lens, the mathmatical model is just the same as in other electromagnetic system. Therefore, the optimzation methods of electromagnetic system can be used to optimize the field in lens. In the end, two examples for optimization are given to verify the new method.

Many scientists have already studied the focus of electron beam, and proposed several ways to analyse the electron beam, such as eikonal method, trajectories way, etc. Based on these,the paper uses the probability function to analyse the focus of electron beam, and treats the emission of electron as a random process. The focus has been attained from the probability of coordinates of trajectories.

In electron beam lithography system,focus ion beam system and cathode ray tubes,the space charge effect caused by the interaction of every particle affects the quality of the device.A lot of scholars have already studied the space charge effect.As so far,Monte Carlo method is often used to calculate the space charge effect in the transportation of particles.This paper tries to use Monte Carlo method to calculate the space charge effect in the beam form region.The 'edge effect' is analysed and some new ways are proposed to decrease the'edge effect' in the simulation.

In the electron beam and ion beam device, the emission system affects the quality of the whole device. Therefore it is very important to analyse the emission system in electron beam device. This paper studies the method of numerical simulation of the electron emission. The planar diode model which is often used to calculate the emission of cathode is discussed and the error caused in the numerical simulation is analysed. On the basis of these discussions, this paper uses another method to simulate the thermal emission of cathode more precisely.

In color monitor tubes, electron optical system influences the quality of the whole tube directly. In the wake of development of HDTV and graphic display in workstation, the quality of color monitor (display) tubes must be improved. For achieving display with high resolution, an axiasymmetric electron optical system is adopted to decrease the size of spot on screen. This paper uses SEU-3D program to simulate electron optical system in color monitor tubes. Taking account of the characters of electron optical system in color monitor tubes, this program uses some special methods to analyse the system so that the result obtained from the simulation can fit the actual condition properly.

Since the structure of deflection system is complicated, FEM (Finite Element Method) may be suitable to calculate the system. However, the deflection field has no definite boundary, it must be taken as an open boundary problem. In view of some peculiarities of deflection system, an improved method FEM-BEM is proposed for analysis. This method is different from ordinary hybrid method, it not only improves the accuracy of deflection traces, but also decreases the requirement for computer speed and memory.