并行电子能量损失谱仪中多重四极透镜系统物方视场的模拟

Simulation about the field of view in multiple lenses system used in parallel electron energy loss spectroscopy

通过对三重四极透镜成像系统的渐晕模拟,研究了并行电子能量损失谱仪中物方视场、漂移管径以及与电荷耦合探测器(CCD)幅面尺寸的对应关系,并由它们间的相互关系确定了与CCD幅面二维探测器尺寸相匹配的漂移管径。

Field of view of a multiple quadropole lenses system was simulated for use in parallel electron energy loss spectroscopy. Based on vignetting factor analysis, it is shown that the field of view are different in the energy non-dispersion plane and in energy dispersion plane, because of the different combination of aperture stop and vignetting stop. The field of view is inversely proportional to the ratio value of aperture angle in energy dispersion plane because of less effect of entrance window（the first quadropole lens as vignetting stop）, but no such simple relation was found in the energy non-disperse plane because the field of view is determined by entrance window（ the third quadropole lens as vignetting stop） in the plane. Our analysis can be used to determine the diameter of drift tube which can be matched with the frame width of the chosen CCD detector.