X射线荧光光谱中散射效应对荧光强度的贡献研究

Calculation of the Contributions of Scattering Effects to the X-Ray Fluorescence Intensities

采用理论计算和实验测定的方法研究了在纯元素样品、BaB二元样品及熔融片样品中三种散射效应对荧光强度的贡献(包括相干散射X射线激发的荧光强度、非相干散射X射线激发的荧光强度以及其他方向的一次荧光X射线被散射进探测方向的强度)大小及其变化规律。研究结果表明,三种散射效应对荧光强度的贡献大小与所研究元素原子特征谱线的能量及样品的基体有关,元素原子的特征谱线能量越高,散射效应对荧光强度的贡献越大;轻基体样品中散射效应对荧光的贡献比重基体样品大。实验证明,将散射效应包括在基本参数法的理论计算中可以有效地提高理论计算的准确度。

The contribution of scattering effects to the X-ray fluorescence intensity was studied for pure element samples, BaB binary samples and fused disk samples by theoretic calculation and experiment. Three scattering effects were considered in the present study, i.e. coherent scattering effect, incoherent scattering effect, and primary fluorescence that was scattered into the direction of detector. The study shows that the contribution of scattering effects to the intensity of fluorescence is related to the energy of the atomic absorption edge, and the sample＇s matrix. The higher the energy of the atomic absorption edge, the more the contribution of scattering effects to the intensity of fluorescence. The contribution of scattering effects to the fluorescence intensity is larger for light matrix samples than heavy matrix samples. The results of experiment show that the accuracy of theoretic calculation was evidently improved when the scattering effects were considered in the theoretic calculation for the intensity of fluorescence.