The Application Research Of Signal Processing Techniques In X-ray Fluorescence Analysis System

X-ray fluorescence analysis is the method of Material composition analysis by using theoriginal X-ray photons to excite atoms in the material under test, thus producing secondarycharacteristic X-ray. The first X-ray fluorescence analyzer was made by H.Friedmann andL.S.Birks in1948. X-ray fluorescence analysis had been demonstrated its importance in the field ofanalysis in1960’s.After1970’s, it had been developed with two branch, wave dispersive and energydispersive X-ray fluorescence.Different element has different energy or wavelength of characteristic X-ray spectrum, and thefluorescence intensity of characteristic spectrum is in a certain relationship with the concentrationof elements. Thus, qualitative and quantitative analysis can be realized by measuring the energyand intensity of X-ray fluorescence spectrum of the material under test. The X-ray fluorescenceanalysis has the advantages of rapid analysis, a wide range of analytical elements, non-destructivetesting and so on. Now it is widely used in industry, mineral, biomedical, environmental Protection,heritage identification and so on. With the development of science and the improvement of X-rayfluorescence method, its applications will further increase the depth and scope.In this paper, the main target is the research of X-ray fluorescence analysis system whichbased on silicon drift detector (SDD), and the application in atmospheric heavy metal detection.This paper mainly studied from the following areas.The first chapter introduced the background of X-ray fluorescence analysis and significance ofthe research, at last established the main tasks of this article.The second chapter introduced the fundamental of X-ray fluorescence analysis, and a briefintroduction of the system components.The third chapter introduced the fundamental and structure of silicon drift detector (SDD), andthe selection of silicon drift detector. Research of some hardware circuit like silicon drift detector’spreamplifier, the drive circuit TEC, and the high voltage bias circuit of silicon drift detector.The fourth chapter, taking the tests of silicon drift detector from energy resolution and countrates. And it had made the tests to research the influence of measured spectrum by change theexcitation conditions and the filter. At last, this part compared the detection limit of system betweenthe system which based on silicon drift detector or Si-PIN detector, and verified the system basedon silicon drift detector was better.The fifth chapter summarized this thesis, summed up their own work, and put forward theprospects for research. This paper used silicon drift detector improved the detection limit of system twice as much asthe system based on Si-PIN detector. And it had discussed about the influential factors of thedetection limit of system, and verified that increased the test time could improve the detection limit.