Boersch effect in electron‐optical instruments
Boersch effect in electron‐optical instruments
复制标题
电子光学仪器中的波尔施效应
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
W. Knauer
中科院分区：
文献类型：
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作者：
W. Knauer
本文分析了电子束和离子束的能量展宽。与早期的治疗不同，本理论考虑了热和交叉运动联合，它包括相对横向运动的光束会聚或发散的变化。给出了圆柱光束、发散光束和光束交叉的能量展宽表达式。计算的增宽水平与文献中给出的实验值进行了比较。将分析应用于色差占主导地位的电子束配置，得到最大电流密度与光斑尺寸的关系。结果表明，对于成像到目标中的场发射源，峰值电流密度与光斑尺寸无关，而对于孔径成像列，最大电流密度与光斑边缘分辨率成反比。
This paper analyzes energy broadening in electron and ion beam. Unlike earlier treatments, the present theory takes into consideration thermal and crossover motions jointly, and it includes changes in relative transverse motion where beams converge or diverge. Expressions are presented for energy broadening in cylindrical beams, diverging beams, and beam crossovers. Calculated broadening levels are compared with experimental values given in the literature. Application of the analysis to electron‐beam configurations in which chromatic aberrations predominate leads to relations for the maximum current density as a function of spot size. It is shown that, for field‐emitting sources, which are imaged into the target, the peak current density is independent of spot size, while, for aperture imaging columns, the maximum current density varies inversely with spot edge resolution.