The Research Of Light Elements EDXRF Analysis

On-site X-ray fluorescence measurement technology ha been well applied in the field of mineral exploration as a field, fast analytical method. But the field of application in domestic oil and gas has few reports, mainly because conventional portable X-ray fluorescence analyzer is not able to measure the Si, Al, Mg, Na and other light elements directly. To a large extent fluorescence analysis of light elements is limited because of the light elements fluorescence low yield, low excitation efficiency and low characteristic X-ray energy and low detection efficiency, and because the energy of light elements’ K lines very close, serious impact matrix effects and other reasons.In this paper, we discussed the relevant technologies of X-ray fluorescence analysis, including the primary level of the background spectrum of the absorption coefficient filters of different materials, matrix effects and calibration study, the degree of vacuum on the X-ray fluorescence measurements impacts. The key point of the paper was focused on the primary level of the background spectrum of different materials absorption coefficient filter. The main content of the paper was below:(1) Due to the little energy of particular X-ray of light elements and easy to be absorbed by air and other media, the particular X-ray can not be measured by the detector, so a vacuum device designed to increase the characteristic X-ray transmission element. The results show that: When the pressure at 200 pa, Na element’ net peak area is 2112, at standard atmospheric pressure, Na element’ net peak area is 590, about 3.58 times improved.(2) The paper studied the resolution, detection efficiency and detection limit of the silicon drift detector(SDD) and Si-PIN detector. New SDD detector was with high energy resolution choozed to raise sensitivity for low energy X-ray.(3) It was a difficult problem to a suitable excitation source for light elements. By comparison of the different parameters miniature X-ray tube, Edix-Ⅲ type X-ray tube, designed in Swiss COMET company, was choozed finally.(4) According to X-ray absorption in matter of law, the absorbing filter can effectively improve the distribution of miniature X-ray tube spectral energy, thus reducing scattering background of low-energy part greatly. MCNP5 was used to research the influence of Emulator X-ray tube filters for primary-line. And the relationship between the material and thickness of the filter and the attenation of original X-ray spectrum was discussed.