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本文是采用Monte Carlo方法,探讨了轻元素定量的EPMA计算的模型及效果。并用其它作者的计算结果进行了比较。本文所提出计算模型的特点是基于单电子多重散射的基本原理,采用了等步长方式去计算当入射电子同试样原子碰撞时所发生的电离以及入射电子的能量损失和运动方向的变化。有关电子散射中能量变化的计算是采用Bethe的连续能量损失公式。根据电子激发的辐射跃迁理论,用Green和Cosslet的原子电离几率公式计算了X射线产生的强度。经过5000个电子的统计计算得到Φ(δz)(它代表X射线产生强度随质量深度分布的函数),然后以Φ(δz)为基础按物质的吸收定律计算其出射强度。
In this paper, Monte Carlo method is used to study the quantitative EPMA calculation model and effect of light element. And compared with the results of other authors. The computational model proposed in this paper is based on the basic principle of single electron multiple scattering and uses an equal-step method to calculate the ionization and the energy loss and movement direction of the incident electrons when the incident electrons collide with the sample atoms. The calculation of energy variations in electron scattering is based on Bethe’s continuous energy loss formula. According to the radiative transition theory of electron excitation, the intensity of X-ray generation is calculated by the atomic ionization probability formula of Green and Cosslet. Φ (δz) (which represents the intensity of X-ray generation as a function of depth of mass distribution) is obtained through the statistical calculation of 5000 electrons, and then the emission intensity is calculated on the basis of Φ (δz) according to the law of absorption of the substance.