Polarization secondary target energy dispersion type X-ray fluorescent spectrograph

Abstract

The invention discloses a polarization secondary target energy dispersion type X-ray fluorescent spectrograph. According to the spectrograph disclosed by the invention, two planes, namely a secondary target and a sample, are arranged on a spatial stereoscopic light path, an X-ray tube of the spectrograph emits primary X rays, the primary X rays are incident to the secondary target in an angle of 45 degrees, scattered rays of the primary X rays emergent from the secondary target in the angle of 45 degrees are full-polarization X rays with polarization direction vertical to an incident plane, and target characteristic X rays excited on the secondary target by the primary X rays are isotropous circular polarization rays and are discrete spectral lines. By adopting the spectrograph disclosed by the invention, peak-to-background ratio is improved, detection limit of microelement detection is reduced, low-content elements in the sample can be detected, and test accuracy and efficiency are improved.

Description

technical field [0001] The invention belongs to a spectrometer, in particular to a polarization secondary target energy dispersion type X-ray fluorescence spectrometer. Background technique [0002] Energy dispersive X-ray fluorescence spectrometry (EDXRF) is widely used in various industries such as production and scientific research due to its advantages of simplicity, quickness, and non-destructive analysis, especially in the detection of environmental protection. pushed to an unprecedented height. [0003] The basic structure of mainstream EDXRF instruments currently on the market is as follows: figure 1 In the two-dimensional design shown, the X-ray tube is excited to generate radiation incident on the sample, and then the sample fluorescence is received by the detector, and then the spectrum is processed and analyzed to obtain the test result. The effective X-ray propagation is restricted in a two-dimensional plane. Such a structure has the advantages of high detecti...

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Problems solved by technology

[0006] At present, for energy dispersive X-ray fluorescence spectrometers, a problem often encountered is that the characteristic X-ray energy of some trace elements that must be detected is just slightly lower than the characteristic X-ray energy of a certain high-content element in the matrix material. In some cases, the detection of trace elements is very difficult due to the low-energy tailing of the characteristic X-rays of high-content elements on the detector (which has little effect on the major elements, but has a great influence on the measurement of trace elements) and / or the escape peak. This has brought great challenges to the application of X-ray fluorescence energy spectrometer. Even if the above-mentioned polarized secondary target light path is used and the selective excitation of the fluorescent secondary target is used, it can only solve the problem that the characteristic X-ray energy of trace elements is significantly lower than In the case of characteristic X-rays of high-content elements, and for the case of characteristic X-rays of trace elements whose energy is slightly lower than that of characteristic X-rays of high-content elements, because the fluorescent X-rays emitted by the fluorescent secondary target have at least two strong spectral lines of different energies , it is difficult to excite only the fluorescence of trace elements to be tested without stimulating the fluorescence of high-content interfering elements at the same time. Although there is some effect, it cannot fundamentally solve the problem. Generally speaking, there is no effective technical means to deal with this situation.

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