Influence of environmental parameter variations on X‐ray beam intensities: a time‐dependent absorption correction
Influence of environmental parameter variations on X‐ray beam intensities: a time‐dependent absorption correction
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环境参数变化对 X 射线束强度的影响：随时间变化的吸收校正
DOI：
10.1107/s1600576715018452
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发表时间：
2015
影响因子：
6.1
通讯作者：
D. Meyer
中科院分区：
文献类型：
--
作者：
T. Weigel;T. Leisegang;M. Zschornak;M. Herrmann;M. Rothenberger;Andreas Wünsche;H. Stöcker;D. Meyer
对于晶体学中X射线分析的质量至关重要，例如衍射法和光谱法，是稳定和可重复的X射线源。通常，利用不同的光学元件来提供专用的X射线束。所有这些部件的稳定对准是减少像差和实现高信噪比的先决条件。除了这种像差和电子引起的X射线原束强度的变化之外，环境条件特别重要，最突出的是气压、湿度和温度。在定性和定量研究中，确定了环境条件对铜阳极密封管的初级束流强度的影响及其相关性。对于一个共同的设置，利用闪烁计数器，实验室以及外部条件同时监测28天。它们对X射线强度的个别影响和它们的相关性通过包括时间滞后的统计分析来评估。通过这项全面的研究，高达I/I = 1.153 0.001%的实验强度的变化被确定在密度的空气变化/ = 3.7 0.6%。这是解释在空气传输的变化高达TX射线= 1.137 0.001%的一个典型的X射线分析设置由于环境气压，温度和湿度的变化，自然中长期的变化。确定了与每日和每周循环，特别是与环境条件的显著相关性。这些结果用于对测量强度进行时间相关吸收校正，从而将标准误差降低约25%。
Essential to the quality of X-ray analysis in crystallography, such as diffractometry and spectrometry, is a stable and reproducible X-ray source. Commonly, different optical elements are utilized to provide a dedicated X-ray beam. The stable alignment of all these components is a prerequisite in order to reduce aberrations and to achieve high signal-to-noise ratios. Besides such aberrations and electronically induced variations of the X-ray primary beam intensity, the environmental conditions are of particular importance, most prominently the barometric pressure, humidity and temperature. In a qualitative as well as quantitative study, the influence of the environmental conditions on the primary beam intensity of a sealed tube with a Cu anode and their correlations are determined. For a common setup, utilizing a scintillation counter, laboratory as well as external conditions are monitored simultaneously for 28 d. Their individual influence on the X-ray intensity and their correlations are evaluated by statistical analysis including time lag. By this comprehensive study, experimental intensity variations of up to I/I = 1.153 0.001% are determined during density of air changes of / = 3.7 0.6%. This is interpreted in terms of air transmission variations of up to TX-ray = 1.137 0.001% for a typical X-ray analysis setup due to ambient barometric pressure, temperature and humidity changes for natural midand long-term variations. Significant correlations with respect to daily and weekly cycles and in particular with ambient conditions are determined. These results are used for a timedependent absorption correction of the measured intensity, which reduces the standard error by about 25%.