Numerical analysis of instrumental resolution effects on strain measurements by diffraction near surfaces and interfaces
Numerical analysis of instrumental resolution effects on strain measurements by diffraction near surfaces and interfaces
复制标题
仪器分辨率对近表面和界面衍射测量应变测量影响的数值分析
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
T. Lorentzen
中科院分区：
文献类型：
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作者：
T. Lorentzen
摘要 使用中子衍射来表征表面或界面附近的应力梯度时，固有的仪器光学相关问题通过数值方法进行了处理。通过衍射装置对相关波长和发散角范围进行射线追踪，结果表明，在表面和界面附近观察到的人工峰移主要归因于计量体积重心远离样品台中心的移动，以及整个照射计量体积的波长分布的不均匀性。已经证明，这两种效应要么是竞争效应，要么是增强效应，具体取决于实验配置。这种洞察力可以用来减少错误，但不能完全消除错误。给出了一些建议以最佳地减少错误，并提供了一些想法以完全消除遇到的错误。
Abstract The inherent instrumental optics related problems in using neutron diffraction to characterise stress gradients near surfaces or interfaces, are treated by a numerical approach. By ray-tracing relevant ranges of wavelengths and divergence angles through a diffraction set-up, it is demonstrated that the artificial peak shifts observed near surfaces and interfaces are mainly attributed to the shift of the gage volume centre of gravity away from the centre of the sample table, and to the inhomogeneity of the wavelength distribution across the irradiated gage volume. It has been demonstrated that these two effects are either competing or reinforcing effects depending on the experimental configuration. This insight can be used to reduce the errors but can not remove them completely. Some recommendations are given for optimum reduction of errors and a few ideas are provided for a complete elimination of the errors encountered.