INVESTIGATION OF ELECTRON BEAM ANALYZER FOR OBSERVING THE SPECIMEN IN THE AIR

点击翻译按钮获取中文摘要

This project is concerned with the development of electron beam analyzer for obsevcing the specimen in the air by using Oligo-scattering electron beam which is using for ESEM.The Oligo-scattering phenomenon in the Be or C foil and air is studied by the theoretical analysis and digital simulation. And the conditions which should be considered in design of the device is reauested.First of all, the requirement to take out Oligo scattering electron beam into air through the Be foil is theoretically derived. Next, the simulation program developed to analyze Oligo-scattering phenomenon is described. This program is based on the Monte Carlo simulation by which the single scattering model is adopted and it is the one with a wide range of application to give the result which is corresponding to analysis and the experimental result well so far.It is shown to be able to calculate the behavior of the electron in the Be or C foil and the air layr (or, substituted gas layr) and to use Oligo-scattering beam within the range of the size which can be achieved by the simulation program. And it is confirmed that Oligo-scattering beam reached the specimen surface by passing the foil and the air layr, and generated back scattering elecrons which can be used for image processing in the model size proposed here. According to the calcuation, several nm spot diameter on the specimen surface could be obtained and the reflection rate of electrons could be 7% forE=40keV,L (Be) =0.2mum and L (Air) =200mum.