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

BackgroundIn the measurement of trace nuclides, the characteristic peaks are easily partly or completely obstructed by the background.PurposeThis 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.MethodsFirst 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 GB5009 15-2014 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.ResultsThe 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.ConclusionThe 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.