XRF能谱多重Sallen-Key平滑滤波方法及其在大米镉含量分析中的应用

Multiple Sallen-Key smoothing filter method of XRF energy spectrum and its application in rice cadmium content analysis

针对痕量核素测量时,特征峰容易部分或全部被背景掩盖,提出多重Sallen-Key(Multiple Sallen-Key,MSK)谱线处理技术,实现在高背景低含量X射线荧光光谱(X-Ray Fluorescence,XRF)分析中的应用。对MSK与多次高斯平滑的对比分析表明,在相同平滑效果下,MSK平滑次数更少,代码执行效率更高。对镉大米标准样的XRF实测谱线,做MSK平滑处理后,可以提高工作曲线的线性。将采用MSK方法分析所得的含量值,与采用GB5009.15-2014方法所得的含量值之间做误差分析,可得MSK处理方法能减小样品含量值的测量误差。本文提出的MSK技术可以有效抑制核能谱中的噪声,提高痕量核素含量的测量精度。

[Background]In the measurement of trace nuclides,the characteristic peaks are easily partly or completely obstructed by the background.[Purpose]This study aims to apply multiple Sallen-Key(MSK)filter to the trace nuclides in X-ray fluorescence(XRF)energy spectrum,and verify its application in rice cadmium content analysis.[Methods]First of all,the principle of MSK filter and implementation method for XRF spectrum processing were introduced in details.The cadmium content in rice standard sample based on GB500915-2014 was determined by graphite furnace atomic absorption spectrometry.Then,the MSK filter compared with multiple Gaussian filter were applied to the XRF spectrum smoothing for the analysis of cadmium content in rice standard samples.Finally,linear calibration and analysis of standard samples were performed to verify the effectiveness of MSK method.[Results]The comparison between MSK and multiple Gaussian filter shows that MSK has less smoothing times and higher code execution efficiency under the same smoothing effect.The error analysis between the content value obtained by MSK method and the content value obtained by GB5009.15-2014 method shows that MSK method can reduce the measurement error of sample.[Conclusion]The MSK technique proposed in this study can effectively suppress the noise in the nuclear energy spectrum and improve the accuracy of the measurement of trace nuclides.