JP2008298679A - Fluorescent x-ray analysis apparatus and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent X-ray analysis apparatus and its method for accurately making an analysis by reducing variation in the statistics of measured values using an intensity ratio between net intensity measured under peak measuring conditions and background intensity measured under background measuring conditions. <P>SOLUTION: This fluorescent X-ray analysis apparatus 10 has an X-ray source 1 irradiating a sample S with primary X-rays 2; detectors 8A, 8B measuring the intensity of secondary X-rays 4 generated from the sample S; a measuring condition setting means 91; a net intensity measuring means 92 storing net intensity In measured under the peak measuring conditions; a background intensity measuring means 93 storing background intensity Ibx measured under the background measuring conditions; an intensity ratio computing means 94 computing the intensity ratio between the net intensity In and the background intensity Ibx; and a quantitative analysis means 95 making a quantitative analysis of the sample S according to the computed arithmetic value In/Ibx. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention irradiates a sample with primary X-rays from an X-ray source, measures the peak intensity and background intensity of fluorescent X-rays generated from the sample, and analyzes the sample according to the calculated value of the intensity ratio. The present invention relates to an X-ray analyzer and a method thereof.

  In order to improve the analysis sensitivity in the microanalysis of fluorescent X-ray analysis, measure with a larger PB ratio (analysis line peak intensity / background intensity intensity ratio) and use measurement conditions that improve the detection limit. Is generally done. Conventionally, a sample is irradiated with primary X-rays from an X-ray source using a fluorescent X-ray analyzer, and the intensity of the analytical line generated from the measurement element present in the sample and the background intensity generated from the sample are determined. An analysis method using a background as an internal standard that can reduce the influence of the matrix of the sample and the fluctuation of the apparatus by measuring with a detector and performing analysis using the intensity ratio is known (see Non-Patent Document 1). ).

In fluorescent X-ray analysis of heavy elements contained in plastic samples, etc., a calibration curve is calculated based on the intensity ratio between the net intensity of the analysis line of the measurement element (the intensity obtained by subtracting the background intensity from the peak intensity) and the background intensity. A method of making the matrix and correcting the sample shape is used. According to this method for analyzing heavy elements such as plastic samples, the net intensity of the analysis line of the measurement element and the scattered X-ray intensity as the background of the same energy as the analysis line of the measurement element are used. This also has the effect of correcting for the effects of
Kozo Momoki, Hiroshi Uchikawa, “X-ray Industrial Analysis Method”, Ohmsha, July 30, 1965, p. 151-154

  In the plastic sample, since the heavy elements as these measurement elements are in a very small concentration, the measurement conditions are used in which the detection limit is improved by measuring with a larger PB ratio (analysis line peak intensity / background intensity). However, since the background intensity is usually reduced when measured under measurement conditions with an improved PB ratio, the intensity ratio between the peak intensity of the analytical line and the background intensity, in other words, the statistics of the intensity ratio between the net intensity and the background intensity. There is a problem that the fluctuation becomes large and the analysis accuracy is lowered.

  Therefore, in the present invention, in order to solve this problem, a background measurement condition that can be measured with a background intensity larger than the background intensity measured under the measurement condition for measuring the net intensity of the analytical line of the measurement element in the sample is set. Using the background intensity measured under the set background measurement conditions, the statistical variation of the intensity ratio of net intensity / background intensity can be reduced, and the X-ray fluorescence analyzer can perform the analysis accurately and accurately. And an object thereof.

  In order to achieve the above object, an X-ray fluorescence analyzer according to a first configuration of the present invention includes an X-ray source that irradiates a sample with X-rays, and a detection that measures the intensity of secondary X-rays generated from the sample. And an X-ray fluorescence analyzer having a measurement condition setting means for setting measurement conditions for the sample, wherein the sample is subjected to primary X-rays from the X-ray source under the peak measurement conditions set in the measurement condition setting means. A net intensity measurement that stores a net intensity obtained by subtracting the background intensity from the peak intensity by irradiating a line, causing the detector to measure the peak intensity and background intensity of fluorescent X-rays of the measurement element generated from the sample And a background measurement condition set in the measurement condition setting means so that measurement can be performed with a background intensity greater than the background intensity measured under the peak measurement condition. The sample is irradiated with primary X-rays from the X-ray source, the background intensity generated from the sample is measured by the detector, and the intensity is stored in the background intensity measuring means and the net intensity measuring means. Quantitative analysis of the sample by the intensity ratio calculation means for calculating the intensity ratio between the stored net intensity and the background intensity stored in the background intensity measurement means, and the calculation value calculated by the intensity ratio calculation means Quantitative analysis means.

  According to the apparatus according to the first configuration of the present invention, since the background intensity larger than the background intensity measured under the peak measurement condition is measured, the statistical variation of the intensity ratio between the net intensity and the background intensity is reduced, Analysis accuracy of fluorescent X-ray analysis is improved.

  An X-ray fluorescence analyzer according to a second configuration of the present invention includes an X-ray source that irradiates a sample with X-rays, a detector that measures the intensity of secondary X-rays generated from the sample, and measurement conditions for the sample. An X-ray fluorescence analyzer having a measurement condition setting means for setting, wherein the sample is irradiated with primary X-rays from the X-ray source under the peak measurement conditions set in the measurement condition setting means, and from the sample There is provided a net intensity measuring means for storing the net intensity obtained by subtracting the background intensity from the peak intensity by causing the detector to measure the peak intensity and background intensity of the fluorescent X-ray of the measurement element to be generated.

  In addition, primary filter switching means for switching a primary filter disposed in an X-ray path of primary X-rays irradiated to the sample from the X-ray source, disposed between the X-ray source and the sample Secondary target switching means for switching the secondary target that is present, spectral element switching means for switching the spectral element generated from the sample and disposed in the X-ray path of the secondary X-ray measured by the detector, the sample and the spectral element First slit switching means for switching the first slit arranged between the second slit switching means for switching the second slit arranged in the secondary X-ray path between the spectroscopic element and the detector. Means, a secondary filter switching means for switching a secondary filter disposed in a secondary X-ray path between the sample and the detector, and a detector used for measurement when there are a plurality of detectors. Detector off And a least one switching means of the device.

  Further, the background measurement set in the measurement condition setting means so that at least one of the switching means included therein is operated and measurement can be performed with a background intensity greater than the background intensity measured under the peak measurement conditions. A background intensity measuring means for irradiating the sample with primary X-rays from the X-ray source under conditions and measuring the background intensity generated from the sample and storing the intensity; and measuring the net intensity Intensity ratio calculating means for calculating an intensity ratio between the net intensity stored in the means and the background intensity stored in the background intensity measuring means, and a sample by the calculated value calculated by the intensity ratio calculating means. And quantitative analysis means for quantitative analysis.

  According to the apparatus of the second configuration of the present invention, since at least one of the switching means is set and measured at a measurement condition capable of measuring a background intensity larger than the background intensity measured at the peak measurement condition, Analysis can be performed with high accuracy in the same manner as the apparatus having the first configuration.

  The X-ray fluorescence analysis method according to the third configuration of the present invention is an X-ray fluorescence analysis method capable of setting measurement conditions for a sample according to the purpose of analysis. The X-ray peak intensity and background intensity of the measurement element generated from the sample is measured with a detector, and the net intensity obtained by subtracting the background intensity from the peak intensity is stored. The sample is set to a background measurement condition that can be measured with a background intensity greater than the background intensity measured under the peak measurement condition, and the sample is irradiated with the primary X-ray from the X-ray source and generated from the sample. Measuring the background intensity with the detector, storing the intensity, and storing the stored net intensity and the stored background measurement condition. In calculating the intensity ratio between the measured background intensity, quantitatively analyzing a sample by using the computed computation value.

  According to the method according to the third configuration of the present invention, since the background intensity greater than the background intensity measured under the peak measurement conditions is measured, the statistical variation in the intensity ratio between the net intensity and the background intensity is reduced. Analysis accuracy of fluorescent X-ray analysis is improved.

  The X-ray fluorescence analysis method according to the fourth configuration of the present invention is an X-ray fluorescence analysis method capable of setting measurement conditions for a sample according to the purpose of analysis. The X-ray peak intensity and background intensity of the measurement element generated from the sample is measured with a detector, and the net intensity obtained by subtracting the background intensity from the peak intensity is stored. To do.

  In addition, primary filter switching means for switching a primary filter disposed in an X-ray path of primary X-rays irradiated to the sample from the X-ray source, disposed between the X-ray source and the sample Secondary target switching means for switching the secondary target that is present, spectral element switching means for switching the spectral element generated from the sample and disposed in the X-ray path of the secondary X-ray measured by the detector, the sample and the spectral element First slit switching means for switching the first slit arranged between the second slit switching means for switching the second slit arranged between the spectroscopic element and the detector, the sample and the detector Among the secondary filter switching means for switching the secondary filter disposed in the secondary X-ray passage between the detector and the detector switching means for switching the detector used for measurement when there are a plurality of detectors. In both cases, one switching means is operated and set to a background measurement condition that can be measured with a background intensity larger than the background intensity measured under the peak measurement condition, and the primary X-ray from the X-ray source is applied to the sample. Irradiate, the background intensity generated from the sample is measured with the detector, and the intensity is stored.

  Further, the intensity ratio between the stored net intensity and the background intensity measured under the stored background measurement condition is calculated, and the sample is quantitatively analyzed using the calculated value.

  According to the method of the fourth configuration of the present invention, since at least one of the switching means is set to the peak measurement condition and the measurement condition is set such that the background intensity larger than the background intensity to be measured can be measured. The analysis can be performed with high accuracy in the same manner as the fluorescent X-ray analysis method having the configuration 3.

The X-ray fluorescence analyzer according to the first embodiment of the present invention will be described below with reference to FIG.
An RhX-ray tube 1 as an X-ray source, and primary filter switching means 3 for switching primary filters 3A, 3B, 3C arranged in a path of the primary X-ray 2 between the RhX-ray tube 1 and the sample S; , 2 selected by the spectroscopic element switching means 6 for switching the spectroscopic elements 6A, 6B, 6C... Arranged in the path of the secondary X-ray 4 generated from the sample S, and the sample S and the spectroscopic element switching means 6. First slit switching means 5 for switching the first solar slits 5A, 5B, 5C arranged between the spectral elements (6B in FIG. 1) arranged in the path of the secondary X-ray 41 and secondary X-rays Detectors 8A and 8B for detecting 4 and detector switching means 8 for switching between them, a spectroscopic element (6B in FIG. 1) selected by the spectroscopic element switching means 6 and disposed in the path of the secondary X-ray 41, and a detector 2nd solar slit 7A arranged between 8A and 8B, A second slit switching means 7 for switching between B and 7C, and a control means 9 having a measurement condition setting means 91, a net intensity measuring means 92, a background intensity measuring means 93, an intensity ratio calculating means 94 and a quantitative analysis means 95. This is a fluorescent X-ray analyzer 10.

  The primary filter switching means 3 includes, for example, a primary filter 3A that is a Ti foil and a primary filter 3C that is an Al foil, which are disposed along the longitudinal direction of a rectangular flat plate, and does not have these metal foils. By having one through-hole 3B (without a primary filter) through which primary X-rays 2 from the RhX-ray tube 1 are transmitted as they are, and moving the rectangular flat plate in a longitudinal direction so as to freely move forward and backward, the primary filter 3A, 3C and the through-hole 3B are selectively switched and are configured to be disposed in front of the RhX-ray tube 1.

  The first solar slit switching means 5 as the first slit switching means is a slide mechanism that slides the high resolution slit 5A, the medium resolution slit 5B, and the low resolution slit 5C having different slit width intervals along the vertical direction with respect to the X-ray path. The first solar slits 5A, 5B, and 5C having different resolutions can be switched by sliding the slide mechanism. The spectroscopic element switching means 6 includes, for example, a spectroscopic element such as a Ge spectroscopic element 6A, a LiF spectroscopic element 6B, and a cumulative multilayer film spectroscopic element 6C fixed to each side surface of the regular octagonal columnar holder and parallel to the side surface of the regular octagonal columnar holder. The spectroscopic elements 6A, 6B, 6C,... Can be switched by rotating around a central axis. The second solar slit switching means 7 as the second slit switching means is a slide mechanism that slides the high resolution slit 7A, the medium resolution slit 7B, and the low resolution slit 7C having different slit width intervals along the vertical direction with respect to the X-ray path. The second solar slits 7A, 7B and 7C having different resolutions can be switched by sliding the slide mechanism.

  When using the SC detector 8A, the scintillation counter (SC) 8A and the gas flow type proportional counter (F-PC) 8B, which are detectors, are more suitable than the F-PC detector 8B. It arrange | positions in series with the X-ray channel | path 43 so that it may become the front. The detector switching means 8 is arranged in a slide mechanism that slides the SC detector 8A along the direction perpendicular to the X-ray passage 43, and the F-PC detector is retracted from the X-ray passage 43. Only 8B is arranged and used in the X-ray passage 43, that is, the detectors 8A and 8B can be switched. The spectroscopic element 6B, the second solar slit 7B, and the detector 8A are configured such that the secondary X-ray 42 is changed to the second solar slit while changing the wavelength of the secondary X-ray 42 dispersed by the spectroscopic element 6B by a goniometer (not shown). 7B and the detector 8A are rotated while maintaining a certain angular relationship.

  The control unit 9 includes a measurement condition setting unit 91, a net intensity measurement unit 92, a background intensity measurement unit 93, an intensity ratio calculation unit 94, and a quantitative analysis unit 95. The net intensity measuring unit 92 and the background intensity measuring unit 93 are configured by a counting circuit, a computer, and the like, and the measurement condition setting unit 91, the intensity ratio calculating unit 94, and the quantitative analysis unit 95 are configured by a computer.

  The measurement condition setting means 91 sets the voltage and current of the RhX-ray tube 1 to predetermined values based on the set peak measurement condition and background measurement condition of the measurement element, and gives an instruction signal to each switching means. The switching means is operated to set the predetermined primary filter, the first and second solar slits, the spectroscopic element, the detector, and the like.

  Here, the peak measurement conditions are conditions that can be measured with a larger PB ratio (analysis line peak intensity Ip / background intensity Ib), and the measurement wavelength of the measurement element is the wavelength of the analysis line unique to the measurement element. The measurement wavelength of the ground is a wavelength in the vicinity of the analysis line unique to the measurement element, and the measurement time of the measurement element and the background is a time appropriately selected in consideration of the PB ratio.

  The background measurement conditions are the same as the peak measurement conditions, such as the voltage and current applied to the X-ray source, the irradiation angle from the X-ray source to the sample, the irradiation distance and irradiation area, and the background measurement wavelength. The conditions of the primary filter, the spectroscopic element, the first and second solar slits, the detector, etc. are the background intensity Ibx larger than the background intensity Ib measured under the peak measurement conditions, for example, the background intensity Ibx is the background intensity Ib. The measurement time is a time appropriately selected in consideration of the PB ratio. If the voltage and current applied to the X-ray source, the irradiation angle from the X-ray source to the sample, the irradiation distance and the irradiation area are the same, the intensity of the analytical line generated from the measurement element and the background intensity of the sample This is because the degree of influence of the matrix is considered to be the same.

  The net intensity measuring unit 92 measures the peak intensity Ip and the background intensity Ib of the measurement element under the peak measurement conditions set by the measurement condition setting unit 91, and the net intensity In () obtained by subtracting the background intensity Ib from the peak intensity Ip. = Ip-Ib).

  The background intensity measurement means 93 measures the background intensity Ibx under the background measurement conditions set by the measurement condition setting means 91, and stores the background intensity Ibx. Here, for the peak and background measurement conditions, the analysis line of the measurement element to be measured by the detectors 8A and 8B, the background measurement wavelength, the analysis line and the detectors 8A and 8B of the background measurement wavelength should be measured. Time, selection of first solar slits 5A, 5B, 5C, selection of second solar slits 7A, 7B, 7C, selection of spectroscopic elements 6A, 6B, 6C, etc., selection of detectors 8A, 8B, primary filter 3A, Selection of 3B, 3C is included. The background measurement condition is at least one switching means among the primary filter switching means 3, the spectroscopic element switching means 6, the first solar slit slit switching means 5, the detector switching means 8, and the second solar slit slit switching means 7. Is set so that it can be measured with an intensity greater than the background intensity measured under the peak measurement conditions. The background measurement wavelength is set to a wavelength close to the analytical line of the measurement element, but is set to a low resolution slit by the first solar slit slit switching means or the second solar slit slit switching means as has been conventionally done. Is also set to a wavelength that is not affected by proximity lines.

  The intensity ratio calculating means 94 calculates the intensity ratio between the net intensity In stored in the net intensity measuring means 92 and the background intensity Ibx stored in the background intensity measuring means 93, and stores the calculated value. . The quantitative analysis means 95 quantitatively analyzes the sample based on the calculated value In / Ibx stored in the intensity ratio calculation means 94.

  Next, the operation for analyzing Cr in the polymer by this apparatus will be described. The peak measurement conditions are the measurement condition setting means 91, Ti primary filter 3A, high resolution first solar slit 5A, high resolution second solar slit 7A, SC detector 8A, peak measurement time is 20 seconds, background The measurement time is 20 seconds, a predetermined voltage and current applied to the RhX-ray tube, a Cr-Kα ray that is an analysis line of Cr as a measurement element, a background measurement wavelength that is a wavelength near the Cr-Kα ray, a LiF spectroscopic element 6B After setting, the measurement is started, and the primary X-ray 2 is irradiated from the RhX-ray tube 1 to the standard sample S1. The LiF spectroscopic element is arranged such that the secondary X-ray 42 is incident on the second solar slit 7B and the SC detector 8A while changing the wavelength of the secondary X-ray 42 dispersed by the spectroscopic element 6B by a goniometer (not shown). 6B, the second solar slit 7B and the SC detector 8A are rotated while maintaining a certain angular relationship, and the Cr-Kα ray generated from the standard sample S1 is measured by the SC detector 8A for 20 seconds, and the peak intensity Ip1 is obtained. It is stored in the net strength measuring means 92.

  Next, the background is measured for 20 seconds with the SC detector 8A at a wavelength near the Cr-Kα ray. The measurement conditions other than the measurement wavelength and the measurement time are the same as when the Cr—Kα ray was measured. The background intensity Ib1 is stored in the net intensity measuring means 92. The net intensity measuring means 92 stores the net intensity In1 (= Ip1-Ib1) obtained by subtracting the background intensity Ib1 from the stored peak intensity Ip1. The standard samples S2, S3 and the polymer sample S0 are measured in the same manner as the standard sample S1, and the net intensity In2 (= Ip2-Ib2) of the standard sample S2, the net intensity In3 (= Ip3-Ib3) of the standard sample S3, and the polymer sample S0. The net intensity Ins (= Ips−Ibs) is stored in the net intensity measuring means 92.

  With the measurement condition setting means 91 as the background measurement condition, the through hole 3B of the primary filter, the low resolution first solar slit 5C, the low resolution second solar slit 7C, the F-PC detector 8B, and the measurement time is 20 seconds. , A predetermined voltage and current to be applied to the RhX ray tube, a background measurement wavelength that is a wavelength in the vicinity of the Cr-Kα ray, and the LiF spectroscopic element 6B are set, and measurement is started. Next, the X-ray 2 is irradiated, the background generated from the standard sample S1 is measured by the F-PC detector 8B for 10 seconds, and the background intensity Ibx1 is stored in the background intensity measuring means 93. The standard samples S2, S3 and the polymer sample S0 are measured in the same manner as the standard sample S1, and the background intensity Ibx2 of the standard sample S2, the background intensity Ibx3 of the standard sample S3, and the background intensity Ibxs of the polymer sample S0 are determined. Store in the measuring means 93. The slit width of the first and second solar slits 5C and 7C is about 10 times as wide as that of the first and second solar slits 5A and 7A.

  The intensity ratio calculating means 94 calculates the intensity ratio between the net intensity and the background intensity corresponding to the standard samples S1, S2, S3 and the polymer sample S0 stored in the net intensity measuring means 92 and the background intensity measuring means 93, respectively. Based on the calculated values In1 / Ibx1, In2 / Ibx2 and In3 / Ibx3 of the calculated standard sample, the quantitative analysis means 95 creates a calibration curve, and the calculated value of the polymer sample S0 which is an unknown sample by the prepared calibration curve Ins / Ibxs is quantified, and the Cr content of the polymer sample S0 is calculated.

  Using the measured value of the polymer sample S0 measured in the present embodiment and using the intensity ratio between the net intensity and the background intensity measured only under the conventional peak measurement conditions, and the peak measurement conditions of the present invention The statistical fluctuation RSD in the case of using the intensity ratio between the measured net intensity and the background intensity measured under the background measurement condition will be described below. Relative accuracy RSDr, which is a statistical fluctuation of the relative value of the intensity ratio of the net intensity and the background intensity, is obtained by the following equation, RSDn is a relative statistical fluctuation of the net intensity, and RSDb is a relative statistical fluctuation of the background intensity.

RSDr = (RSDn ² + RSDb ² ) ^1/2

  The measured values of the polymer sample S0 measured in this embodiment were the following intensities.

  Ips: 0.8186 kcps, Ibs: 0.0348 kcps, Ibxs: 19.3709 kcps

  The results of calculating the relative accuracy RSD of the net intensity and background intensity from these intensities are described below. The relative accuracy RSDns of net strength is

RSDns = (Ips−Ibs) ⁻¹ (Ips / 20 + Ibs / 20) ^1/2 (1/1000) ^1/2 = 0.0083

  The accuracy RSDbs of the background intensity Ibs under peak measurement conditions is

RSDbs = (Ibs) ⁻¹ (Ibs / 20) ^1/2 (1/1000) ^1/2 = 0.0379

  The accuracy RSDbxs of the background intensity Ibxs under the background measurement condition is

RSDbxs = (Ibxs) ⁻¹ (Ibxs / 10) ^1/2 (1/1000) ^1/2 = 0.0016

  It is.

  The relative accuracy RSDrp of the intensity ratio between the net intensity Ins and the background intensity Ibxs when measured only under the peak measurement condition is

  RSDrp = 0.0388

  The relative accuracy RSDrpx of the intensity ratio between the net intensity Ins measured under the peak measurement conditions and the background intensity Ibxs measured under the background measurement conditions is

  RSDrpx = 0.0084

  The relative accuracy RSDrpx is improved to about 1/5 of the relative accuracy RSDrp. Thus, when measured using the intensity ratio of the net intensity measured under the peak measurement conditions of the present embodiment and the background intensity measured under the background measurement conditions, the background is greater than the background intensity measured under the peak measurement conditions. Since the measurement is based on intensity, statistical fluctuations are greatly improved, and extremely accurate analysis can be performed.

  In the present embodiment, the primary filter, the first solar slit, the second solar slit, and the detector were set to a background measurement condition that can be measured with a background intensity greater than the background intensity measured under the peak measurement condition. However, any one or two of these may be switched to measure at a background intensity greater than the background intensity measured under the peak measurement conditions. In addition, the spectroscopic element may be switched and measurement may be performed by setting the background measurement condition that allows measurement with a background intensity greater than the background intensity measured under the peak measurement condition. Moreover, although the peak and the background were determined under the peak measurement conditions, the background may be measured at two points. Alternatively, only the peak may be measured under the peak measurement conditions, and the quantitative analysis may be performed using the intensity ratio between the gross peak intensity and the background intensity obtained under the background measurement conditions.

  A fluorescent X-ray analyzer according to a second embodiment of the present invention will be described with reference to FIG. RhX ray tube 1 as an X-ray source, primary filter switching means 300 for switching a primary filter disposed in a path of primary X-ray 2 between RhX ray tube 1 and sample S, and secondary X-ray X-rays comprising a semiconductor detector 800 for detecting 4, a measurement condition setting means 91, a net intensity measurement means 92, a background intensity measurement means 93, an intensity ratio calculation means 94, and a quantitative analysis means 95. This is an analyzer 100. The primary filter switching means 300 includes a primary filter 300A, which is a Ti plate, a primary filter 300C, which is a Cu plate, and the like, which are arranged along the circumference of the disc. The primary filters 300A and 300C have one through-hole 300B (without a primary filter) through which primary X-rays from the ray tube pass as they are, and the discs are rotated around the central axis of the disc. And the through-hole 300B can be switched.

  The operation of the fluorescent X-ray analyzer according to this embodiment will be described. The peak measurement conditions are the measurement condition setting means 91, the primary filter 300A, the measurement time is 40 seconds, the predetermined voltage and current to be applied to the RhX-ray tube, the Cr—Kα line as the analysis line of the measurement element, Cr— After setting the background measurement wavelength, which is the wavelength near the Kα ray, measurement is started, the primary sample S1 is irradiated with the primary X-ray 2 from the RhX ray tube 1, and the Cr—Kα ray generated from the standard sample S1 is semiconductor. The detector 800 is caused to measure for 40 seconds, and the peak intensity Ip 1 and the background intensity Ib 1 are stored in the net intensity measuring means 92. The net intensity measuring means 92 stores the net intensity In1 (= Ip1-Ib1) obtained by subtracting the background intensity Ib1 from the stored peak intensity Ip1. The other standard samples S2 and S3 and the unknown sample S0 are measured in the same manner as described above, and the respective net intensities are stored in the net intensity measuring means 92.

  The background measurement conditions are the measurement condition setting means 91, the through hole 300B (no primary filter), the measurement time is 20 seconds, the predetermined voltage and current applied to the RhX-ray tube, and the back wavelength which is the vicinity wavelength of the Cr-Kα line After setting to the ground measurement wavelength, the measurement is started, the standard sample S1 is irradiated with the primary X-ray 2 from the RhX-ray tube 1, and the background generated from the standard sample S1 is measured with the semiconductor detector 800 for 20 seconds. The ground strength Ibx1 is stored in the net strength measuring means 92. The other standard samples S2, S3 and the unknown sample S0 are measured in the same manner as described above, and the respective background intensities are stored in the background intensity measuring means 93.

  The intensity ratio calculating means 94 calculates the intensity ratio between the net intensity and the background intensity corresponding to the standard samples S1, S2, S3 and the unknown sample S0 stored in the net intensity measuring means 92 and the background intensity measuring means 93, respectively. In the same manner as in the first embodiment, the quantitative analysis means 95 is made to calculate the content of the measurement element of the unknown sample S0.

  In the present embodiment, the measurement is performed by switching to the through hole 300B (without the secondary target) by the primary filter switching means so that the measurement can be performed with a background intensity larger than the background intensity measured under the peak measurement conditions. Statistical fluctuation is greatly improved, and extremely accurate analysis can be performed.

  In the present embodiment, the background measurement condition is measured by setting the through hole 300B (without the primary filter) that can be measured with a background intensity larger than the background intensity measured with the primary filter under the peak measurement condition. Is equipped with a secondary filter switching means for switching the secondary filter arranged between the detector and the detector. Under peak measurement conditions, a secondary filter is set for measurement, and under background measurement conditions, there is no secondary filter. Thus, the measurement may be performed with a background intensity greater than the background intensity measured under the peak measurement conditions.

  In the first and second embodiments of the present invention, the calibration curve method is used. However, the unknown sample may be quantified by the FP method (fundamental parameter method) using the calculated value calculated by the quantitative analysis means. Moreover, although the RhX ray tube was illustrated as an X-ray source, another X-ray tube, a rotary anode type | mold X-ray generator, etc. may be sufficient. The X-ray fluorescence analyzer may be either a wavelength dispersion type or an energy dispersion type. In the first and second embodiments, the measurement is performed by switching the primary filter, but the measurement is performed by switching the secondary target using the secondary target switching means arranged between the X-ray tube and the sample. May be.

1 is a schematic diagram showing a fluorescent X-ray analyzer according to a first embodiment of the present invention. It is the schematic which shows the fluorescent-X-ray-analysis apparatus of 2nd Embodiment of this invention.

Explanation of symbols

1 X-ray source X-ray tube 2 Primary X-ray 3 Primary filter switching means 4 Secondary X-ray 5 First solar slit switching means 6 Spectroscopic element switching means 7 Second solar slit switching means 8 Detector switching means 10, 100 X-ray fluorescence analyzer 91 Measuring condition setting means 92 Net intensity measuring means 93 Background intensity measuring means 94 Intensity ratio calculating means 95 Quantitative analyzing means 300 Primary filter switching means S Sample

Claims (4)

An X-ray source for irradiating the sample with X-rays;
A detector for measuring the intensity of secondary X-rays generated from the sample;
Measurement condition setting means for setting the measurement condition of the sample;
A fluorescent X-ray analysis apparatus comprising:
The sample is irradiated with primary X-rays from the X-ray source under the peak measurement conditions set in the measurement condition setting means, and the peak intensity and background intensity of the fluorescent X-ray of the measurement element generated from the sample are detected. A net intensity measuring means for storing a net intensity obtained by subtracting the background intensity from the peak intensity;
Irradiate the sample with primary X-rays from the X-ray source under the background measurement conditions set in the measurement condition setting means so that measurement can be performed with a background intensity greater than the background intensity measured under the peak measurement conditions. Background intensity measuring means for causing the detector to measure the background intensity generated from the sample and storing the intensity;
Intensity ratio calculating means for calculating an intensity ratio between the net intensity stored in the net intensity measuring means and the background intensity stored in the background intensity measuring means;
Quantitative analysis means for quantitatively analyzing the sample by the calculated value calculated by the intensity ratio calculating means;
X-ray fluorescence analyzer. An X-ray source for irradiating the sample with X-rays;
A detector for measuring the intensity of secondary X-rays generated from the sample;
Measurement condition setting means for setting the measurement condition of the sample;
A fluorescent X-ray analysis apparatus comprising:
The sample is irradiated with primary X-rays from the X-ray source under the peak measurement conditions set in the measurement condition setting means, and the peak intensity and background intensity of the fluorescent X-ray of the measurement element generated from the sample are detected. A net intensity measuring means for storing a net intensity obtained by subtracting the background intensity from the peak intensity;
Primary filter switching means for switching a primary filter disposed in an X-ray path of primary X-rays irradiated to the sample from the X-ray source, and a secondary disposed between the X-ray source and the sample Secondary target switching means for switching the target, spectral element switching means for switching the spectral element generated from the sample and measured in the X-ray path of the secondary X-ray measured by the detector, between the sample and the spectral element A first slit switching means for switching the first slit disposed in the first, a second slit switching means for switching the second slit disposed between the spectroscopic element and the detector, and between the sample and the detector. At least one of the secondary filter switching means for switching the secondary filter disposed in the secondary X-ray passage and the detector switching means for switching the detector used for measurement when there are a plurality of detectors. And a switching means,
The background measurement condition set in the measurement condition setting means so that at least one of the switching means included in the switch is operated and measurement can be performed with a background intensity greater than the background intensity measured under the peak measurement condition. A background intensity measuring means for irradiating the sample with primary X-rays from the X-ray source, causing the detector to measure the background intensity generated from the sample, and storing the intensity;
Intensity ratio calculating means for calculating an intensity ratio between the net intensity stored in the net intensity measuring means and the background intensity stored in the background intensity measuring means;
Quantitative analysis means for quantitatively analyzing the sample by the calculated value calculated by the intensity ratio calculating means;
X-ray fluorescence analyzer. In the fluorescent X-ray analysis method capable of setting the measurement conditions of the sample according to the analysis purpose,
Set the peak measurement conditions, irradiate the sample with primary X-rays from the X-ray source, measure the peak intensity and background intensity of the fluorescent X-ray of the measurement element generated from the sample with the detector, and the peak intensity The net intensity obtained by subtracting the background intensity from is stored,
A background measurement condition that can be measured with a background intensity greater than the background intensity measured under the peak measurement condition is set, and the sample is irradiated with primary X-rays from the X-ray source, and a background generated from the sample is generated. Measure the ground strength with the detector, store the strength,
Calculating the intensity ratio between the stored net intensity and the background intensity measured under the stored background measurement conditions;
A fluorescent X-ray analysis method for quantitatively analyzing a sample using the calculated calculated value. In the fluorescent X-ray analysis method capable of setting the measurement conditions of the sample according to the analysis purpose,
Set the peak measurement conditions, irradiate the sample with primary X-rays from the X-ray source, measure the peak intensity and background intensity of the fluorescent X-ray of the measurement element generated from the sample with the detector, and the peak intensity The net intensity obtained by subtracting the background intensity from is stored,
Primary filter switching means for switching a primary filter disposed in an X-ray path of primary X-rays irradiated to the sample from the X-ray source, and a secondary disposed between the X-ray source and the sample Secondary target switching means for switching the target, spectral element switching means for switching the spectral element generated from the sample and measured in the X-ray path of the secondary X-ray measured by the detector, between the sample and the spectral element A first slit switching means for switching the first slit disposed in the first, a second slit switching means for switching the second slit disposed between the spectroscopic element and the detector, and between the sample and the detector. At least one of the secondary filter switching means for switching the secondary filter disposed in the secondary X-ray passage and the detector switching means for switching the detector used for measurement when there are a plurality of detectors. Is switched to a background measurement condition that can be measured with a background intensity greater than the background intensity measured under the peak measurement condition, and the sample is irradiated with primary X-rays from the X-ray source. , Measure the background intensity generated from the sample with the detector, store the intensity,
Calculating the intensity ratio between the stored net intensity and the background intensity measured under the stored background measurement conditions;
A fluorescent X-ray analysis method for quantitatively analyzing a sample using the calculated calculated value.

Images