Research On X-ray Fluorescence Analyzer Based On Carbon Nanotubes Cold Cathode

As an important analysis method,X-ray fluorescence spectrum analysis technology has the advantages of simple sample preparation,wide analysis element range,wide linear range,non-destructive testing,fast and convenient,etc.compared with other analysis technologies,therefore,it is widely used in Industrial manufacturing,geological exploration,environmental testing,medicine and health,food safety and archaeological research.However,domestic high-performance X-ray fluorescence analysis equipment has long relied on imports and is expensive.As the core device of X-ray fluorescence spectrometer,high-performance X-ray source and detector have long been monopolized by foreign countries.In order to meet the increasing market demand and improve the competitiveness of domestic X-ray fluorescence spectrometry equipment,this paper carried out a research based on carbon nanotube cold cathode X-ray fluorescence spectrometer.The main research contents are as follows:(1)In-depth study on the process of preparing carbon nanotube cathode using microwave plasma enhanced chemical vapor deposition equipment.Using photolithography,coating,growth and other processes,a carbon nanotube array cathode perpendicular to the substrate is grown on the silicon substrate.The length and density of carbon nanotubes are controlled by controlling the thickness and growth parameters of the catalyst.(2)After testing and veteranizing the prepared carbon nanotube cathode,a glass encapsulation process was used to prepare a carbon nanotube field emission cold cathode X-ray source.Through testing,it was found that the maximum DC emission current density of the carbon nanotube field emission cathode reached 65.8A/cm~2.(3)In-depth research and analysis of X-ray fluorescence spectrum qualitative and quantitative analysis algorithms,comparative analysis of various processing algorithms available at each step,and the optimal algorithm was selected as the algorithm of X-ray fluorescence spectrum processing software.(4)Based on the MATLAB platform,I wrote a set of simple X-ray fluorescence spectrum processing software.Spectral processing software includes three modules:data management,qualitative analysis and quantitative analysis.The data management module is mainly used to manage the basic parameters of the X-ray fluorescence spectrometer.The qualitative analysis module first performs spectral processing on the original spectrum,and then identifies the types of elements contained in the sample to be tested.The quantitative analysis module uses the basic parameter method to correct the absorption enhancement effect,and then iteratively solves for the concentration of the element to be measured.(5)An energy dispersive X-ray fluorescence spectrometer based on a carbon nanotube field emission cold cathode was developed for experimental analysis.Through the qualitative and quantitative analysis of the Ag-Cu-Ni alloy,it is found that the qualitative analysis can better identify all the elements to be measured.Quantitative analysis results show that for the measurement of major elements,the standard deviation is small,while for the measurement of minor elements,the standard deviation is large.Finally,for the existing errors,the causes are analyzed.