CN2145381Y

CN2145381Y - X-ray fluorescence analyser using X-ray lens

Info

Publication number: CN2145381Y
Application number: CN 93200633
Authority: CN
Inventors: 颜一鸣
Original assignee: Beijing Normal University
Current assignee: Beijing Normal University
Priority date: 1993-01-19
Filing date: 1993-01-19
Publication date: 1993-11-03
Anticipated expiration: 2003-01-19

Abstract

The utility model relates to an X-ray fluorescence analyser using an X-ray lens (an X-ray buncher). The X-ray in the larger solid angle transmitted by an X-ray tube can be focused into a microbeam spot whose diameter is the millimeter to the micrometre through the X-ray lens. Thus, the power density of the beam spot is improved, the power of the X-ray source is relatively reduced, and the energy can be saved. The microbeam spot can be used for testing the spatial distribution of elements in a sample. Because the X-ray lens reduces the background caused by the scattered radiation of the high-energy X-ray, the utility model improves the signal-to-noise ratio. As a consequence, the detection limit of the instrument is improved.

Description

X-ray fluorescence analyser using X-ray lens

The present invention relates to a kind of x-ray fluorescence analyzer that is used for measuring the sample constituent content.

X-ray fluorescence analysis (XRF) is a kind of important means of constituent content analysis, physics, chemistry, chemical industry, metallurgy, biology, medical science, learn, be widely used in many scientific researches such as material science, space flight and aviation and microelectronics or the industrial circle.In recent years, in order to increase signal to noise ratio (S/N ratio), improve sensitivity and analysis speed, to carry out micro-zone analysis etc., some progress have been obtained technically.Mainly contain three kinds of methods: the one, utilize the polarization X-ray, initial X-ray is got on the crystal polarization sheet, produce the polarization X-ray, this polarization X-ray is got on the sample, inspire characteristic X-ray, the normal direction on probe plane is parallel with the polarised direction of polarization X-ray on getting to sample, the polarization X-ray can not be propagated in that this side up, has therefore reduced the interference of the feature X-ray that the incident X-ray launches sample.Referring to documents＜ENERGY-DISPERSIVE FLUORESENCE ANALYSIS USING BRAGG-REFLECTED PORARIZED X-RAYS 〉, H.Aiginger, P.Wobrauschek and C.Brauner, NUCLEAR INSTRUMENTS AND METHODS120(1974), 541-542.The 2nd, utilize total reflection principle, make the limiting slit of the X-ray of incident by two 0.05mm, form pencil, get on the sample reverberator with the incident angle very little with respect to sample plane, total reflection is gone out again, has reduced the scattering background that initial incident X-ray causes.Referring to documents＜TOTAL REFLECTION X-RAYFLUORESENCE ANALYSIS WITH POLARIZED X-RAYS, A COMPACT ATTACHMENT UNIT, ANDHIGH ENERGY X-RAYS 〉, Peter Wobrauschek and Peter Kregsamer, SPECTROCHIM.ACTA 44B, No.5,453-460, (1989).But, more than the X ray intensity got on the sample of two kinds of methods very weak, can not carry out micro-zone analysis.The 3rd, synchrotron Radiation X-Ray Fluorescence Analysis, synchrotron radiation X-ray is a polarized light, and intensity is big, and collimation is good, can improve sensitivity and reduce background, as obtaining the micron bundle with the restriction of light hurdle, also can carry out micro-zone analysis.But the device of generation synchrotron radiation as synchronous accelerator, costs an arm and a leg, and is difficult to as the conventional analysis means.

The new X ray fluorescence analytical equipment that the purpose of this invention is to provide a kind of utilization " X-ray beam forming system " (being x-ray lens).Because the X-ray beam forming system can be converged to the X ray of dispersing very little bundle spot, improve the power density of X-ray greatly, thereby improved sensitivity for analysis, and can reduce the power of X-ray pipe again, save electric energy.Because x-ray lens has certain passband, the best X-ray wave band in the time of can selecting to analyze, thus card falls the background that high-energy X-ray causes, improves sensitivity for analysis, the expansion detection limit.Be converged to very that the X-ray of tuftlet spot can be used for micro-zone analysis, obtain the information that element space distributes in the sample.That installs is simple in structure, and cost is not high, and is easy to use and universal.

The present invention is x-ray fluorescence analysis (XRF) instrument of a kind of use x-ray lens (X-ray beam buncher).X-ray lens wherein is made up of the X-ray conduit.Photoconductive tube is hollow tubule.Photoconductive tube has two kinds of single tube and complex pipes, and single tube is a hollow tubule, and complex pipe then is made of tens of to thousands of single tubes.At first, the X-ray of quite big solid angle is collected and is assembled by x-ray lens (2) in the X-ray that the anode (1) of X-ray pipe is launched, and forms the microbeam spot, below the beam spot diameter, number millimeter, even reach tens of microns, can carry out micro-zone analysis, the space distribution of various elements in the working sample.Secondly, because x-ray lens has been collected the X-ray of dispersing in a large number, be converged to the microbeam spot, the power density of bundle spot is very big, and is bigger 1,000 to 1,000,000 times than the bundle spot power density of common X-ray fluorescence analyser.Therefore, compare with common X-ray fluorescence analyser, as get same analysis speed and analysis limit, then the power of X-ray pipe can reduce 100 to 1,000 times.The X-ray that has not only reduced cost but also reduced environment pollutes.The 3rd, because x-ray lens has certain service band, can chosen in advance during design, the X-ray that is higher than the predetermined band upper energy limit will not be focused, and the X-ray that is lower than predetermined band energy lower limit then can be absorbed in air He on the photoconductive tube tube wall.Thereby reduced the background that the high-energy X-ray scattering causes, improved the signal background ratio, improved the detection limit of instrument greatly, for example, the detection limit of copper, iron and zinc can reach 1.0ng-0.1ng.

Be embodiment below:

One of embodiment: Fig. 1 (a) is a kind of x-ray fluorescence analyzer that uses x-ray lens.X-ray from copper anode (1) outgoing of X-ray pipe is collected and is assembled by x-ray lens (2), focus point is on sample (3), form the microbeam spot below the diameter number millimeter, sample plane becomes miter angle with the incident X-ray, the feature X-ray of emission was mapped on the detector (4) along the directions that become 90 degree with incident X-ray bundle after element in the sample (3) was excited, and analyzed and stored through amplification and computer multichannel analyzer.

X-ray lens is made up of compound X-ray conduit, 0.4 millimeter of photoconductive tube internal diameter.Long 459 millimeters of lens, 47 millimeters of maximum gauges, about 23 degree of collection angle.Lens left side focal length is 10 millimeters, and right focal length is 30 millimeters.The energy range of X-ray transmission is greatly between 5keV-15keV.0.5 millimeter of X-ray beam spot diameter, after lens focus.Experiment shows that after the x-ray lens pack, the power density of focus place X-ray has strengthened 10,000 times.

Two of embodiment: Fig. 1 (b) is on the basis of the foregoing description, increases by second x-ray lens (5).These lens are collected the feature X-ray of sample emission and converge on the detector, further improve detection sensitivity.

Claims

1, a kind of instrument that is used for working sample constituent content and space distribution thereof, this instrument is made up of X-ray pipe, sample end liner, detector, Amplifier And Computer multichannel analyzer etc., it is characterized in that utilizing one or more x-ray lens (being the X ray beam buncher) with the X-ray of incident or/and can gather from the feature X-ray of sample outgoing.

2, device according to claim 1 is characterized in that having increased the x-ray lens of being made up of a large amount of photoconductive tubes between X-ray pipe and sample.

3, device according to claim 1 is characterized in that having increased the x-ray lens of being made up of a large amount of photoconductive tubes between sample and detector.

4, device according to claim 1 is characterized in that increasing x-ray lens between X-ray pipe and the sample and between sample and detector.