JP2014145617A - Energy dispersive fluorescent x-ray analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy dispersive fluorescent X-ray analyzer capable of appropriately identifying the peak of characteristic X-rays obtained by an element to be measured even if the temperature is changed.SOLUTION: An energy dispersive fluorescent X-ray analyzer comprises: an X-ray source 1 emitting excitation X-rays A including characteristic X-rays of an energy E1 generated from a target; a correcting body 8 for allowing the excitation X-rays A to generate characteristic X-rays of an energy E2 as corrected X-rays; a detector 4 for detecting fluorescent X-rays B generated from a sample simultaneously with the excitation X-rays A and the corrected X-rays; a pulse height analyzer 5; and an operation unit 6. The operation unit 6 corrects a relation between an energy value and a peak value, based on a peak value H1 at a peak apex on the basis of the characteristic X-rays of the energy E1 and a peak value H2 at a peak apex on the basis of the characteristic X-rays of the energy E2.

Description

  The present invention relates to an energy dispersive X-ray fluorescence analyzer. More specifically, the present invention relates to an energy dispersive X-ray fluorescence analyzer that can accurately identify a peak of characteristic X-rays obtained from an element to be measured even when there is a temperature change of a detector or the like.

The X-ray fluorescence analyzer identifies or quantifies a measurement target element in a sample using fluorescent X-rays emitted by irradiating the sample with excitation X-rays. If the X-ray fluorescence contains characteristic X-rays specific to the element to be measured in the sample, the presence of the element to be measured can be confirmed, and the quantitative information of the element to be measured can be obtained from the count value of the characteristic X-ray. Can be obtained.
There are two types of X-ray fluorescence analyzers: wavelength-dispersion type and energy-dispersion type. Among them, energy-dispersion type X-ray fluorescence analyzers can be miniaturized because they do not require a spectroscopic system. Is used.

Conventionally, an energy dispersive X-ray fluorescence analyzer has been used under strict temperature control (for example, Patent Document 1). This is because the detector is particularly susceptible to temperature, and even X-rays of the same energy (wavelength) are detected as peaks at different peak values due to temperature changes.
Further, the high voltage applied to the detector is feedback-controlled by detecting the position shift of the peak value of the scattered light of the excitation X-ray, and if it is the X-ray of the same energy (wavelength), strict temperature management is performed. It has also been proposed to obtain a peak at a constant peak value without any change (Patent Document 2).

Registered Utility Model No. 3075377 Japanese Patent Laid-Open No. 04-274745

However, if temperature management is performed as in Patent Document 1, a large-scale system for temperature management is required. In addition, even if temperature control is strictly performed, there are cases where a constant temperature cannot be maintained, for example, when the environmental temperature changes greatly. In particular, when a proportional counter is used as a detector, the influence of temperature change is large, which may hinder accurate analysis.
Moreover, even if feedback control is performed so that the positional shift of the peak value of the scattered light of the excitation X-ray does not occur as in Patent Document 2, the energy value (wavelength) and the peak value are not in a simple proportional relationship. For this reason, the peak value of the peak based on the characteristic X-ray inherent to the element to be measured in the sample still cannot avoid temperature fluctuation.
The present invention has been made in view of the above circumstances, and provides an energy dispersive X-ray fluorescence analyzer capable of accurately identifying a characteristic X-ray peak obtained from an element to be measured even when there is a temperature change. To do.

In order to achieve the above object, the present invention employs the following configuration.
[1] An energy dispersive X-ray fluorescence analyzer that analyzes a measurement target element in the sample based on fluorescent X-rays generated by irradiating the sample with excitation X-rays,
An X-ray source that emits excitation X-rays including characteristic X-rays of energy E1 generated from the target;
A correction body provided so as to block a part of the light beam of the excitation X-ray from the X-ray source to the sample, and generating a characteristic X-ray of energy E2 as the correction X-ray by the excitation X-ray;
A detector that detects fluorescent X-rays generated from the sample simultaneously with the excitation X-ray and the correction X-ray;
A pulse height analyzer for converting the output of the detector into a spectrum having a peak value corresponding to an energy value as a horizontal axis and a count value as a vertical axis;
A calculation unit for obtaining information of an element to be measured in the sample from a spectrum obtained from the wave height analyzer,
The calculation unit corrects the relationship between the energy value and the peak value from the peak value H1 at the peak apex based on the characteristic X-ray of the energy E1 and the peak value H2 at the peak apex based on the characteristic X-ray of the energy E2,
An energy dispersive X-ray fluorescence analyzer characterized by identifying a peak at a peak value Hx corresponding to a characteristic X-ray of energy Ex of an element to be measured in a sample as a peak based on the element to be measured in the sample .
[2] The energy dispersive X-ray fluorescence spectrometer according to [1], wherein the detector is a proportional counter.
[3] The energy dispersive X-ray fluorescence spectrometer according to [1] or [2], wherein the element constituting the target is titanium or scandium, and the element constituting the correction body is aluminum or silicon.
[4] The energy dispersive X-ray fluorescence spectrometer according to any one of [1] to [3], wherein the measurement target element in the sample is sulfur.
[5] The energy dispersive X-ray fluorescence spectrometer according to any one of [1] to [4], wherein the sample is petroleum.
[6] Furthermore, a beam of excited X-rays made of the same element as the element constituting the target or an element whose atomic number is one larger than that of the element constituting the target and reaching the sample from the X-ray source. A filter provided between the X-ray source and the corrector for filtering,
The arithmetic unit corrects the count value at each peak value based on the peak count value based on the characteristic X-ray of the energy E1, and the peak based on the characteristic X-ray of the energy E1 is a half of the peak peak on the low peak side. Is determined by inverting the half of the high wave height side with the peak value H1 at the peak apex as the folding axis, and obtaining the peak count value based on the characteristic X-ray of the energy Ex. The energy dispersive X-ray fluorescence spectrometer according to any one of [1] to [5], which obtains quantitative information.

The peak value in the present invention means not the original X-ray energy value itself but the energy value recognized by the detector.
In addition, in this specification, scattering means elastic scattering in which energy (wavelength) does not change.
Further, in this specification, the peak count value means an integrated value of the peak count value in principle, but may be a count value at the peak apex when a sharp peak is obtained. Further, the integrated value of the peak count value may be an integrated value of count values within a certain range from the peak apex of the peak, or may be an integrated value of the entire count value of the peak.

According to the energy dispersive X-ray fluorescence analyzer of the present invention, the peak of characteristic X-rays obtained from the element to be measured can be accurately identified even when there is a temperature change.
Therefore, the temperature management system of the apparatus can be omitted or simplified, and accurate analysis can be performed with a simple apparatus.

1 is a configuration diagram of an energy dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention. It is an example of the transmittance | permeability curve of the filter of FIG. It is explanatory drawing of the optical path where a correction | amendment X-ray reaches a detector. It is explanatory drawing about another correction body. An example of a spectrum when measuring a zero liquid not containing sulfur as a measurement target element by an energy dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention in which the target and the filter are titanium and the correction body is aluminum. is there. It is the elements on larger scale of FIG. An example of a spectrum when a span liquid containing a known amount of sulfur as a measurement target element is measured by an energy dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention in which the target and the filter are titanium and the corrector is aluminum. It is. It is explanatory drawing of the calculation method of the net count value of a sulfur peak. It is explanatory drawing of the calculation method of the net count value of a sulfur peak. It is explanatory drawing of the calculation method of the net count value of a sulfur peak.

An energy dispersive X-ray fluorescence analyzer according to an embodiment of the present invention will be described. As shown in FIG. 1, an energy dispersive X-ray fluorescence spectrometer of this embodiment includes an X-ray source 1 that emits excitation X-rays A, a high-voltage power source 2 that applies high-voltage power to the X-ray source 1, and a flow cell through which a sample flows. 3. Detector 4 provided on the optical path of excitation X-ray A scattered by the sample or flow cell 3 and fluorescent X-ray B emitted from the sample, pulse height analyzer 5 to which the output of detector 4 is input, pulse height analysis An operation unit 6 is provided for obtaining information on the element to be measured in the sample from the spectrum obtained by the vessel 5.
A filter 7 and a correction body 8 are sequentially provided in the optical path of the excitation X-ray A from the X-ray source 1 to the flow cell 3. A sample introduction path 11 and a sample discharge path 12 are connected to both ends of the flow cell 3, respectively. The optical path of the excitation X-ray A from the X-ray source 1 to the flow cell 3 and the optical path of the excitation X-ray A and the fluorescent X-ray B from the sample to the detector 4 are those of the fluorescent X-ray B such as helium and nitrogen in a vacuum environment. It is preferably formed in a single gas atmosphere that does not impede permeation.

  The X-ray source 1 is provided with a target (not shown) inside a vacuumed housing. By colliding high-speed electrons with the target, a characteristic X-ray of energy E1 peculiar to the elements constituting the target is generated. The excited X-ray A including the characteristic X-ray of the energy E1 is emitted. The high-voltage power supply 2 applies a high voltage to the X-ray source 1 in order to generate this high-speed electron.

As an element constituting the target, a solid target material such as Sc, Ti, Ag, Rh, Mo, Cu, Cr, W, Co, or Fe can be used. Since the energy E1 of characteristic X-rays differs depending on the type of element constituting the target, it may be appropriately selected according to the element to be measured in the sample.
Since the excited X-ray A generates characteristic X-rays of the energy Ex of the measurement target element as fluorescence, it is essential that the energy E1 is sufficiently larger than the energy Ex. Therefore, the element constituting the target must be larger than the element to be measured. On the other hand, if the energy E1 is excessively larger than the energy Ex, characteristic X-rays of an element larger than the element to be measured are also generated, resulting in a decrease in measurement accuracy.
For example, when the measurement target element in the sample is sulfur (Kα = 2.31 keV), titanium (Kα = 4.51 keV) or scandium (Kα = 4.09 keV) is preferably used as the element constituting the target. it can.

The flow cell 3 is provided with an X-ray transmissive window on the side where the excitation X-ray A from the X-ray source 1 is incident. As the window, a beryllium thin film is usually used.
As the detector 4, a known detector such as a proportional counter, a semiconductor detector, or a scintillation counter can be employed. Among them, the proportional counter is easily affected by temperature, and therefore the present invention can be preferably applied. If the proportional counter can solve the problem of the influence of temperature, a small amount of X-rays can be detected with a high output, so that it is suitable for measuring a trace amount of an element to be measured. A beryllium thin film is usually used also for the window of the detector 4.
The detector 4 is arranged at a position where the X-ray fluorescence B emitted from the sample and the excitation X-ray A scattered by the flow cell 3 and the corrected X-ray C described later can be detected at the same time.

  The wave height analyzer 5 converts the output of the detector 4 into a spectrum with the wave height value corresponding to the energy value as the horizontal axis and the count value as the vertical axis. Specifically, the peak value range for obtaining the spectrum is divided into a number of channels (2048, 4096, etc.), and the spectrum is obtained by counting the detected X-rays for each divided channel.

  The filter 7 is provided at a position that blocks the excitation X-ray A so as to filter the light beam of the excitation X-ray A from the X-ray source 1 to the flow cell 3. The filter 7 is composed of a thin film of the same element as that constituting the target of the X-ray source 1 or an element having an atomic number that is one larger than that of the element constituting the target. For example, when the element constituting the target is titanium, titanium or vanadium can be adopted as the element constituting the filter 7. When the element constituting the target is scandium, scandium or titanium can be employed as the element constituting the filter 7.

The X-ray permeability of the filter 7 is sufficiently high in the characteristic X-ray energy E1 of the elements constituting the target, gradually decreases as the energy becomes lower than the energy E1, and rapidly decreases when the energy E1 is exceeded.
For example, as shown in FIG. 2, the transmittance of the filter made of titanium gradually decreases as it becomes lower than 4.96 with 4.96 keV as the peak apex, and rapidly decreases when the energy exceeds E1. In FIG. 2, a transmittance of 1.0 means 100% transmission.
Therefore, when the element constituting the target is titanium (Kα = 4.51 keV) or scandium (Kα = 4.09 keV), the characteristic X-ray of the element constituting the target is obtained by filtering with the filter 7 made of titanium. The white X-rays in the excitation X-ray A can be reduced while sufficiently transmitting. In addition, characteristic X-rays that cause noise due to elements (for example, iron, nickel, cobalt) and the like constituting the casing of the X-ray source 1 can be cut.

The corrector 8 generates the characteristic X-ray of the energy E2 as the corrected X-ray C by the excitation X-ray A. The energy E2 is obviously smaller than the energy E1 of the characteristic X-ray in the excitation X-ray A, but is preferably smaller than the energy Ex of the characteristic X-ray of the element constituting the measurement target element in the sample. Since the energy Ex is between the energy E1 and the energy E2, the peak value Hx corresponding to the energy Ex can be obtained more accurately.
For example, when the element to be measured in the sample is sulfur (Kα = 2.31 keV), the elements constituting the correction body 8 are aluminum (Kα = 1.49 keV), silicon (Kα = 1.74 keV), sodium (Kα = 1.04 keV) and magnesium (Kα = 1.25 keV) can be employed. Among these, aluminum and silicon are preferable because they are stable as a simple substance, and aluminum is particularly preferable because it is easy to process as a pure substance. When sodium or magnesium is used, it must be used as a stable compound such as an oxide.

  As schematically shown in FIG. 3, the correction body 8 of the present embodiment has a structure including an opening 8a. The opening 8a can be a pinhole or a slit, and is preferably a pinhole. By using the opening 8a as a pinhole, the correction body 8 can also serve as a stop for the excitation X-ray A. For example, the excitation X irradiated from the X-ray source 1 toward the flow cell 3 by disposing the correction body 8 having a pinhole having a diameter of about 2 mm at a position closest to the X-ray source 1 (about 1 to 5 mm). A part of the light flux of the line A is blocked by the correction body 8, but the central part of the light flux passes through the pinhole (opening 8 a) and reaches the flow cell 3.

  The correction X-ray C is generated from the entire portion of the correction body 8 where the excitation X-ray A hits, but what is detected by the detector 4 is the correction X-ray C generated mainly at the edge portion of the opening 8a. A part of the corrected X-ray C generated at the edge portion of the opening 8a reaches the flow cell 3 through an optical path substantially equivalent to the excitation X-ray A as shown in FIG. It reaches the detector 4 through an optical path substantially equivalent to that of the X-ray B. The other part reaches the detector 4 directly as shown in FIG. The detector 4 may be arranged so as to detect only the corrected X-ray C that has passed through the optical path shown in FIG. 3A, or only the corrected X-ray C that has passed through the optical path shown in FIG. You may arrange | position so that it may detect.

The corrector 8 may be deposited on the cell window of the flow cell 3 as schematically shown in FIG. Also in this case, the correction body 8 has an opening 8a, and the opening 8a is a substantial cell window. The shape of the opening 8a can be a pinhole or a slit. In this case, the correction X-ray C is generated from the whole of the correction body 8 that is exposed to the excitation X-ray A, and reaches the detector 4 and is detected directly. For example, the correction body 8 can be provided in a ring shape with the center of the cell window as the center point.
Moreover, you may form the correction | amendment body 8 not by the structure which has an opening part in part, but vapor-depositing continuously or intermittently in a part of peripheral part of a cell window. For example, the correction body 8 can be provided in an intermittent ring shape with the center of the cell window as the center point.
Since the correction X-ray C only needs to confirm the peak value H2 at the peak apex, the count value obtained by the detector 4 may be extremely small. If the count value obtained by the detector 4 is too large, an overlap between the peak of the corrected X-ray C and the peak based on the characteristic X-ray of the element to be measured causes an error, which is not preferable.

The calculation unit 6 obtains information about the element to be measured in the sample from the spectrum obtained from the wave height analyzer 5.
Hereinafter, taking as an example the case where sulfur in petroleum is measured by the energy dispersive X-ray fluorescence spectrometer of the present embodiment in which the target of the X-ray source 1 and the filter 7 are titanium and the corrector 8 is aluminum, the computing unit 6 is An example of steps for identifying sulfur, which is a measurement target element in a sample, from the spectrum obtained from the wave height analyzer 5 and further obtaining quantitative information will be described.

In the following description, the peak count value means an integrated value of count values within a certain range from the peak apex of the peak. From the viewpoint of obtaining a stable numerical value, the constant width is preferably 5 channels or more, more preferably 10 channels or more, as the number of channels of the wave height analyzer 5. In addition, from the viewpoint of suppressing errors due to overlapping with other peaks, the half width of each peak is preferably equal to or less than half, and more preferably half or less of the half value width.
In the following, based on an example in which the total number of channels of the wave height analyzer 5 is 2048, and the peak count value is an integrated value of 21 channel count values including a channel including the peak apex and 10 channels before and after that. explain.

(Measurement of zero solution)
First, a zero solution that does not contain sulfur, which is an element to be measured, is passed through the flow cell 3. As the zero liquid, for example, liquid paraffin, decalin and the like can be used.
FIG. 5 is an example of a spectrum obtained at that time, and FIG. 6 is a partially enlarged view thereof. As shown in FIG. 5, the aluminum peak is so small that it cannot be confirmed in FIG. 5 of the whole spectrum, but the expansion can be clearly confirmed as shown in FIG.

Based on the peak value H1 of the peak peak of titanium of energy E1 (Kα = 4.51 keV) and the peak value H2 of peak value of aluminum of energy E2 (Kα = 1.49 keV), other peak values are also related to the energy value. It is done.
The energy E to which the peak values H other than the peak values H1 and H2 correspond can be obtained by the following equation.
E = (E1-E2) * (H-H2) / (H1-H2) + E2
5 and 6, it is assumed that the peak value H1 of the peak of titanium is energy E1 (Kα = 4.51 keV), and the peak value H2 of the peak of aluminum is energy E2 (Kα = 1.49 keV). FIG. 5 is a diagram in which all the crest values are associated with energy values, and the relationship between the energy values and crest values is corrected (corrected on the horizontal axis).

(Measurement of span liquid)
Next, a span liquid containing a known amount of sulfur as an element to be measured is passed through the flow cell 3. As the span liquid, for example, liquid paraffin or decalin in which a known amount of dibutyl sulfide or dibutyl disulfide is dissolved can be used.
FIG. 7 is an example of the spectrum of the span liquid obtained under temperature conditions that are not the same as those when measuring the zero liquid. The “raw spectrum” in FIG. 7 is a spectrum as it is without any correction. The “live spectrum” titanium peak appears in different magnitudes at different peak values than the titanium peak in FIG. In FIG. 7, the aluminum peak cannot be confirmed, but if it is enlarged as in FIG. 6, the aluminum peak can also be confirmed in this “raw spectrum”.
The peak appearing on the slightly higher wavelength side than 2 keV is the sulfur peak.

The horizontal axis corrected spectrum is obtained by correcting the relationship between the energy value and the peak value for this raw spectrum. In the correction of the relationship between the energy value and the peak value, the peak value H1 of the peak of titanium is assumed to be energy E1 (Kα = 4.51 keV) as described in the measurement of the zero solution, and the peak peak of aluminum is assumed. Assuming that the peak value H2 is energy E2 (Kα = 1.49 keV), all peak values are associated with energy values.
If the span liquid contains a relatively high concentration (for example, about 500 ppm) of sulfur, a sulfur peak can be identified without correcting the horizontal axis. In the apparatus of the present embodiment, the peak value Hx corresponding to the energy Ex (Kα = 2.31 keV) of the characteristic X-ray of sulfur can be obtained by the following formula, so that sulfur at an extremely low concentration (for example, about 10 ppm) is obtained. Even the peak of can be identified.
Hx = (H1-H2) * (Ex-E2) / (E1-E2) + H2

Next, the vertical axis correction spectrum is obtained by correcting the count value (vertical axis correction) with respect to the horizontal axis correction spectrum. The vertical axis correction is performed based on the count value of the titanium peak.
Specifically, the scale of the vertical axis is changed so that the count value of the titanium peak in the horizontal axis correction spectrum is the same as the count value of the titanium peak obtained by the measurement of the zero solution. In the present embodiment, the peak count value is an integrated value of the count value for 21 channels including the channel including the peak apex and the 10 channels before and after that, and therefore the channel including 4.51 keV and the 21 channels including the 10 channels before and after the channel. The area of the width of the minute is made to be the same as that of the titanium peak obtained by the measurement of the zero solution.
In the vertical axis correction, it is not always essential to use the titanium peak count value obtained by measuring the zero solution as a reference. For example, the count value of another peak obtained by measuring the span liquid may be expressed as the ratio to the count value of the titanium peak obtained by measuring the span liquid.

In the obtained vertical axis correction spectrum, the sulfur peak overlaps the tail of the titanium peak. Therefore, in order to obtain the net count value of the sulfur peak, it is necessary to determine the position of the tail of the titanium peak.
Therefore, in the present embodiment, the peak based on the characteristic X-rays of titanium is obtained by inverting the half of the low wave height side with the peak value H1 (Kα = 4.51 keV) of the peak peak at the peak side of the high wave height. Considering that there is a peak count value based on the characteristic X-rays of energy Ex.

  It can be considered that the low wave height side half is obtained by inverting the high wave height side half with the peak value H1 at the peak apex as the folding axis. In this embodiment, since the titanium filter is used, the peak height of titanium is high. This is because characteristic X-rays such as iron (Kα = 1.94 keV), cobalt (Kα = 1.79 keV), nickel (Kα = 1.66 keV) and the like which may overlap with the wave height side are cut. Therefore, the high peak side half of the titanium peak can be regarded as a peak shape based on net titanium. Since the X-ray peak of a single energy value (wavelength) originally has a shape that conforms to a Gaussian distribution or a Gaussian distribution, the low wave height side half turns the peak value H1 of the peak apex from the high wave height half. It can be considered that it is reversed.

FIG. 8 is a diagram in which the folded spectrum obtained by inverting the vertical axis corrected spectrum obtained in FIG. 7 with the peak height H1 (Kα = 4.51 keV) at the peak peak half as the folding axis is superimposed. is there.
When the folding spectrum is subtracted from the vertical axis correction spectrum at the peak value H1 (Kα = 4.51 keV) or less, a net peak of sulfur is obtained as shown in FIG. 9, and therefore the count value and span of the net peak are obtained. Span calibration can be performed based on the relationship with the sulfur concentration of the liquid.

Considering that the peak of titanium is the half of the peak of the low peak, the half of the peak of the peak is inverted with the peak of the peak of the peak of the peak of the high peak H1 (Kα = 4.51 keV) as the turning axis. The method for obtaining the net count value is not limited to the above. For example, if the high peak side half of the titanium peak obtained by the measurement of the zero liquid is subtracted from the high peak side half of the titanium peak in the vertical axis correction spectrum, a differential spectrum as shown in FIG. 10 is obtained.
The difference spectrum obtained by inverting the peak value H1 (Kα = 4.51 keV) as the folding axis is subtracted from the vertical axis correction spectrum, and further obtained by measuring zero liquid at a peak value H1 (Kα = 4.51 keV) or less. When the spectrum is subtracted, a net peak of sulfur is obtained, so span calibration can be performed from the relationship between the count value of the net peak and the sulfur concentration of the span solution.

(Sample measurement)
Next, a sample (petroleum) whose sulfur content as an element to be measured is unknown is passed through the flow cell 3. The spectrum processing in this case is the same as in the case of the span liquid.
That is, the spectrum of the sample obtained under temperature conditions that are not the same as when measuring the zero solution or the span solution is the titanium peak of the zero solution or the span solution in the “raw spectrum” without any correction. And appear in different magnitudes at different peak values. In the “raw spectrum”, the sulfur peak appears at a peak value different from the sulfur peak of the span liquid. Therefore, using the aluminum peak detected at the same time, the horizontal axis is corrected in the same manner as described for the span liquid.

  Further, the vertical axis correction is performed in the same manner as described for the span liquid to obtain a vertical axis correction spectrum. Further, the peak of titanium in the vertical axis correction spectrum was regarded as the half of the low wave height side being inverted with the peak value H1 (Kα = 4.51 keV) of the peak peak at the peak side of the high wave height. Above, find the net count value of the sulfur peak. The specific method for obtaining the net count value is the same as that described for the span solution. By comparing this count value with the net count value of the sulfur peak in the span liquid, the sulfur content in the sample can be determined.

According to the present embodiment, since the horizontal axis correction is performed at two points of the characteristic X-ray of the target of the X-ray source 1 and the characteristic X-ray of the element constituting the correction body, even if there is a temperature change, The characteristic X-ray peak obtained can be accurately identified.
Further, since the vertical axis correction is performed based on the characteristic X-ray of the target of the X-ray source 1, and the peak of the measurement target element is calculated in consideration of the peak tail based on the characteristic X-ray of the target, The measurement element can be accurately quantified.
Accordingly, the temperature management system of the apparatus can be omitted or simplified, and accurate analysis can be performed with a simple apparatus.

Further, when a proportional coefficient tube is used as a detector, a small amount of X-rays can be detected with high output. Conventionally, proportional coefficient tubes are easily affected by temperature changes and it is difficult to obtain a sharp peak. Therefore, even if a high output is obtained for a very small amount of a measurement target element, the characteristic X-ray skirt of the target of the X-ray source 1 can be obtained. It was difficult to accurately determine the peak count value of the net measurement target element, and it was difficult to measure a trace amount of the measurement target element. According to the present embodiment, it is possible to accurately quantify a trace amount of an element to be measured using a proportional counter as a detector without strictly controlling the temperature.
For example, when sulfur in petroleum is measured by the energy dispersive X-ray fluorescence spectrometer of this embodiment in which the target of the X-ray source 1 and the filter 7 are titanium and the corrector 8 is aluminum, the concentration is extremely low at 1 ppm or less. Even sulfur can be quantified.

  In the present invention, it is not essential to obtain the quantitative information by the calculation unit 6. In that case, the filter can also be omitted.

  DESCRIPTION OF SYMBOLS 1 ... X-ray source, 2 ... High voltage power supply, 3 ... Flow cell, 4 ... Detector, 5 ... Wave height analyzer, 6 ... Calculation part, 7 ... Filter, 8 ... Correction body, A ... Excitation X-ray, B ... Fluorescence X Line, C ... corrected X-ray

Claims (6)

An energy dispersive X-ray fluorescence analyzer that analyzes a measurement target element in the sample based on fluorescent X-rays generated by irradiating the sample with excitation X-rays,
An X-ray source that emits excitation X-rays including characteristic X-rays of energy E1 generated from the target;
A correction body provided so as to block a part of the light beam of the excitation X-ray from the X-ray source to the sample, and generating a characteristic X-ray of energy E2 as the correction X-ray by the excitation X-ray;
A detector that detects fluorescent X-rays generated from the sample simultaneously with the excitation X-ray and the correction X-ray;
A pulse height analyzer for converting the output of the detector into a spectrum having a peak value corresponding to an energy value as a horizontal axis and a count value as a vertical axis;
A calculation unit for obtaining information of an element to be measured in the sample from a spectrum obtained from the wave height analyzer,
The calculation unit corrects the relationship between the energy value and the peak value from the peak value H1 at the peak apex based on the characteristic X-ray of the energy E1 and the peak value H2 at the peak apex based on the characteristic X-ray of the energy E2,
An energy dispersive X-ray fluorescence analyzer characterized by identifying a peak at a peak value Hx corresponding to a characteristic X-ray of energy Ex of an element to be measured in a sample as a peak based on the element to be measured in the sample .   The energy dispersive X-ray fluorescence spectrometer according to claim 1, wherein the detector is a proportional counter.   The energy dispersive X-ray fluorescence spectrometer according to claim 1 or 2, wherein the element constituting the target is titanium or scandium, and the element constituting the correction body is aluminum or silicon.   The energy dispersive X-ray fluorescence spectrometer according to any one of claims 1 to 3, wherein the element to be measured in the sample is sulfur.   The energy dispersive X-ray fluorescence spectrometer according to any one of claims 1 to 4, wherein the sample is petroleum. Furthermore, it is configured to filter the excitation X-ray light flux that is composed of the same element as the element constituting the target or an element whose atomic number is one larger than that of the element constituting the target and that reaches the sample from the X-ray source. A filter provided between the X-ray source and the correction body,
The arithmetic unit corrects the count value at each peak value based on the peak count value based on the characteristic X-ray of the energy E1, and the peak based on the characteristic X-ray of the energy E1 is a half of the peak peak on the low peak side. Is determined by inverting the half of the high wave height side with the peak value H1 at the peak apex as the folding axis, and obtaining the peak count value based on the characteristic X-ray of the energy Ex. The energy dispersive X-ray fluorescence analyzer according to any one of claims 1 to 5, wherein quantitative information is obtained.

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