CN112051289A - X-ray analyzer and peak search method - Google Patents
X-ray analyzer and peak search method Download PDFInfo
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Abstract
The invention provides an X-ray analysis apparatus and a peak search method. The peak search process includes a coarse sweep process (S230) and a fine sweep process (S260). The coarse scanning process (S230) acquires a profile for the first wavelength range. The jog scan process (S260) acquires a profile about a second wavelength range which includes a peak position of the profile acquired by the jog scan process (S230) and is narrower than the first wavelength range. The measurement time of each measurement point in the coarse scanning process (S230) is shorter than the measurement time of each measurement point in the fine scanning process (S260).
Description
Technical Field
The present disclosure relates to an X-ray analysis apparatus and a peak search method.
Background
An X-ray Analyzer such as an Electron Probe Microanalyzer (EPMA) or a fluorescent X-ray Analyzer is known to be equipped with a Wavelength dispersion type Spectrometer (WDS).
Jp-a-8-31367 discloses a peak search method that can easily and accurately determine the wavelength (peak position) at which the intensity is maximum in the spectrum of a characteristic X-ray separated by a wavelength dispersion type spectrometer in an X-ray analysis device including the spectrometer.
By accurately determining the peak position from the profile of the spectrum of the characteristic X-ray (hereinafter, sometimes simply referred to as "profile") separated by the spectroscope, it is possible to improve the accuracy of "quantitative analysis" for measuring the concentration of an element contained in a sample, for example. In the quantitative analysis, in order to measure the concentration of a target element, after the intensity of the peak position is measured using a standard sample whose concentration of the element is known, the intensity of the peak position is measured under the same measurement conditions for a sample whose concentration of the element is unknown, and the concentration of the element in the sample is measured from the intensity ratio thereof.
The profile obtained by using the wavelength dispersion type Spectrometer has a characteristic that a peak is steep and is less likely to overlap with peaks of other characteristic X-rays than a profile obtained by using an Energy dispersion type Spectrometer (EDS), and is susceptible to a shift in wavelength depending on reproducibility of mechanical operation (operation of a goniometer) of the Spectrometer, a shift in wavelength depending on a chemical bonding state of an element, and the like. Therefore, the following processes are generally performed in an X-ray analyzer including a wavelength dispersion type spectrometer: the spectral wavelengths are scanned in the vicinity of the peak position assumed from the target element, and the peak position is accurately determined from the profile obtained by performing the scanning, that is, "peak search" is performed to align the spectral wavelengths.
In the peak search, a scanning process is performed in which the profile near the peak position is acquired by measuring the characteristic X-rays one by one for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays to be detected changes at predetermined intervals. As an example, the scanning range is set to be about several times (e.g., 3 times to 4 times) the half width of the expected contour, about 40 points are marked in the scanning range, and 0.75 seconds of measurement is performed for each point, and the scanning process is performed for about 30 seconds in total.
However, due to statistical variations in the X-ray signal to be measured, the shape of the profile obtained in the peak search may change. When the shape of the contour changes, the peak position may be erroneously determined, and when the spectral wavelength that deviates from the true peak position is measured, an error occurs in the measured intensity, and an error occurs in the concentration measurement result.
Statistically, the error in intensity (the count of characteristic X-rays detected by the detector) is used
(σ represents a standard deviation, and N represents a number of counts), and therefore, for example, in a profile in which the intensity of the peak position is 10000 counts, an error of 100 counts is included in the standard deviation of 1 σ, and there is a deviation of the intensity of about 1%. Therefore, even a wavelength position whose intensity is lower by about 1% than the original peak may be determined as the peak position, and an error in the peak position may cause an error in the quantitative analysis.
In order to reduce the error caused by the statistical variation, it is effective to increase the measurement time of each measurement point in the peak search processing (increase the count value), but if the measurement time of each measurement point needs to be doubled in order to halve the error, the time required for performing the peak search increases significantly. Although it is also conceivable to reduce the scanning range of the peak search by an amount corresponding to the amount by which the measurement time is extended, there is a possibility that the peak search fails because the peak is not included in the scanning range.
Disclosure of Invention
The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide an X-ray analyzer and a peak search method that can realize a high-precision peak search without increasing a processing time.
The disclosed X-ray analysis device is provided with: a wavelength dispersion type optical splitter; and a processing device configured to execute a peak search process of detecting a peak position of a spectrum of the characteristic X-ray separated using the spectroscope. The peak search processing includes a scanning process in which the spectral profile is acquired by measuring the characteristic X-rays one by one for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays changes at predetermined interval steps. The scanning process includes a first scanning process and a second scanning process. The first scanning process acquires a profile for a first wavelength range. The second scanning process acquires a profile regarding a second wavelength range that includes a peak position of the profile acquired by the first scanning process and is narrower than the first wavelength range. The first predetermined time, which is the predetermined time for the first scanning process, is shorter than the second predetermined time, which is the predetermined time for the second scanning process.
In addition, the peak search method of the present disclosure is a peak search method for detecting a peak position of a spectrum of a characteristic X-ray separated using a wavelength dispersion type spectrometer, and includes a first step and a second step. In the first step, the profile of the spectrum in the first wavelength range is acquired by measuring the characteristic X-rays one by one for a first predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays changes at predetermined interval steps. In the second step, the spectrometer is operated so as to change the wavelength of the characteristic X-rays at predetermined intervals, and the characteristic X-rays are measured one by one for a second predetermined time, thereby acquiring a profile of the spectrum in a second wavelength range which includes the peak position of the profile acquired in the first step and is narrower than the first wavelength range. The first predetermined time in the first step is shorter than the second predetermined time in the second step.
The above and other objects, features, aspects and advantages of the present disclosure will become apparent from the following detailed description, which is to be read in connection with the accompanying drawings.
Drawings
Fig. 1 is an overall configuration diagram of an EPMA as an example of an X-ray analysis apparatus according to an embodiment of the present disclosure.
Fig. 2 is a diagram showing an example of a profile of a characteristic X-ray.
Fig. 3 is a graph showing in detail the signal intensity in the vicinity of the peak position of the profile shown in fig. 2.
Fig. 4 is a diagram showing a scanning range of the jog scan.
Fig. 5 is a diagram showing an example of the rough movement condition and the fine movement condition.
Fig. 6 is a graph showing the signal intensity in the vicinity of the peak position.
Fig. 7 is a flowchart showing an example of a procedure of quantitative analysis using the EPMA according to the present embodiment.
Fig. 8 is a flowchart showing an example of the procedure of the measurement processing executed in step S20 and step S40 of fig. 7.
Fig. 9 is a flowchart showing an example of the procedure of the peak search processing executed in step S150 in fig. 8.
Fig. 10 is a graph showing the signal intensity in the vicinity of the peak position.
Fig. 11 is a flowchart showing an example of the procedure of the peak search processing in the modification.
Fig. 12 is a diagram showing another example of the rough movement condition and the fine movement condition.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.
< construction of X-ray analysis apparatus >
Fig. 1 is an overall configuration diagram of an EPMA as an example of an X-ray analysis apparatus according to an embodiment of the present disclosure. The X-ray analyzer of the present disclosure is not limited to EPMA that irradiates a sample with an electron beam, and may be a fluorescent X-ray analyzer that irradiates a sample with an X-ray and disperses a characteristic X-ray by WDS.
Referring to fig. 1, EPMA 100 includes an electron gun 1, a deflection yoke 2, an objective lens 3, a sample stage 4, a sample stage driving unit 5, and a plurality of spectrometers 6a and 6 b. The EPMA 100 further includes a control unit 10, a data processing unit 11, a deflection coil control unit 12, an operation unit 13, and a display unit 14. The electron gun 1, the deflection yoke 2, the objective lens 3, the sample stage 4, and the spectroscopes 6a and 6b are provided in a measurement chamber not shown, and the measurement chamber is evacuated to a vacuum state during X-ray measurement.
The electron gun 1 is an excitation source that generates an electron beam E to be irradiated onto the sample S on the sample stage 4, and can adjust the beam current of the electron beam E by controlling a focusing lens (not shown). The deflection yoke 2 forms a magnetic field by a drive current supplied from the deflection yoke control unit 12. The electron beam E can be deflected by the magnetic field formed by the deflection coil 2.
The objective lens 3 is provided between the deflection yoke 2 and the sample S placed on the sample stage 4, and reduces the electron beam E passing through the deflection yoke 2 to a small diameter. The electron gun 1, the deflection yoke 2, and the objective lens 3 constitute an irradiation device for irradiating the sample with electron beams. The sample stage 4 is a stage on which the sample S is placed, and is configured to be movable in a horizontal plane by a sample stage driving unit 5.
By driving the sample stage 4 by the sample stage driving unit 5 and/or driving the deflection coil 2 by the deflection coil control unit 12, the irradiation position on the sample S to which the electron beam E is irradiated can be scanned two-dimensionally. When the scanning range is relatively narrow, scanning is performed by the deflection coil 2, and when the scanning range is relatively wide, scanning is performed by moving the sample stage 4.
The spectroscopes 6a and 6b are devices for detecting characteristic X-rays emitted from the sample S irradiated with the electron beam E. In this example, two splitters 6a and 6b are shown, but the number of splitters is not limited to this, and may be one, or three or more. The structures of the spectroscopes other than the spectroscopic crystal are the same, and hereinafter, each spectroscope may be simply referred to as "spectroscope 6".
The spectrometer 6a includes a spectroscopic crystal 61a, a detector 63a, and a slit 64 a. The irradiation position of the sample S with the electron beam E, the spectroscopic crystal 61a, and the detector 63a are located on a rowland circle, not shown. By a drive mechanism not shown, the spectroscopic crystal 61a is tilted while moving on the straight line 62a, and the detector 63a is rotated as shown in the drawing in accordance with the movement of the spectroscopic crystal 61a so that the incident angle of the characteristic X-ray with respect to the spectroscopic crystal 61a and the output angle of the diffracted X-ray satisfy the bragg diffraction condition. This enables wavelength scanning of the characteristic X-ray emitted from the sample S.
The spectrometer 6b includes a spectroscopic crystal 61b, a detector 63b, and a slit 64 b. The structure of the spectroscope 6b other than the spectroscopic crystal is the same as that of the spectroscope 6a, and therefore, description thereof will not be repeated. The configuration of each spectrometer is not limited to the above configuration, and various known configurations can be adopted.
The control Unit 10 includes a CPU (Central Processing Unit) 20, a Memory (ROM (Read Only Memory) and RAM (Random Access Memory)) 22, and an input/output buffer (not shown) for inputting and outputting various signals. The CPU loads the programs stored in the ROM into the RAM and the like and executes them. The program stored in the ROM is a program in which a processing procedure of the control unit 10 is recorded. The ROM also stores various tables (diagrams) used for various operations. The control unit 10 executes various processes in the EPMA 100 according to the programs and the tables. The processing is not limited to being executed by software, and may be executed by dedicated hardware (electronic circuit).
The data processing unit 11 is also configured to include a CPU, a memory (ROM and RAM), and an input/output buffer (neither shown) for inputting and outputting various signals. The data processing unit 11 creates an X-ray spectrum of the analysis target, and performs qualitative analysis based on the X-ray spectrum. The data processing unit 11 also performs peak search of a standard sample and an unknown sample including an element to be measured by characteristic X-rays corresponding to the element, and performs quantitative analysis based on the peak search. The data processing unit 11 may be integrated with the control unit 10.
The deflection coil control unit 12 controls the drive current supplied to the deflection coil 2 in accordance with an instruction from the control unit 10. By controlling the drive current in accordance with a predetermined drive current pattern (magnitude and changing speed), the irradiation position on the sample S to which the electron beam E is irradiated can be scanned at a desired scanning speed.
The operation unit 13 is an input device for an analyst to give various instructions to the EPMA 100, and is configured by, for example, a mouse, a keyboard, and the like. The display unit 14 is an output device for providing various information to the analyst, and is configured by, for example, a display including a touch panel that can be operated by the analyst. The touch panel may be the operation unit 13.
< method of quantitative analysis >
In quantitative analysis, the concentration of a target element (hereinafter referred to as "target element") in a sample is measured. In the quantitative analysis, in order to measure the concentration of an object element, after an intensity at a peak position of a characteristic X-ray corresponding to the object element (hereinafter referred to as "peak intensity") is measured using a standard sample whose concentration of the object element is known, the peak intensity is measured for a sample whose concentration of the object element is unknown under the same measurement conditions, and the concentration of the object element in the sample is measured from the intensity ratio thereof.
Therefore, by accurately obtaining the peak positions of the characteristic X-rays corresponding to the target elements for the standard sample and the unknown sample, the accuracy of the quantitative analysis can be improved. In an X-ray analyzer including a wavelength dispersion type spectrometer, a spectral wavelength is scanned in the vicinity of a peak position assumed from an object element, and the peak position is accurately specified from a profile obtained by performing the scanning, that is, "peak search" is performed.
Fig. 2 is a diagram showing an example of the profile of the characteristic X-ray to be measured. The outline shown here is an outline obtained by a conventional method as a reference example. In fig. 2, the horizontal axis represents the wavelength (spectral wavelength) of the detected characteristic X-ray, and the vertical axis represents the signal intensity (cps) of the detected characteristic X-ray.
Referring to fig. 2, the contour qualitatively has a shape of a substantially normal distribution. The black dots on the curve represent the measurement points. That is, in the peak search, a scanning process is performed in which the beam splitter is operated so as to change the wavelength of the characteristic X-ray to be detected at predetermined intervals, and the characteristic X-ray is measured one by one for a predetermined time, thereby obtaining a profile as shown in the drawing.
In this reference example, a scanning range is set to be about several times (e.g., 3 to 4 times) the half width of an expected contour from past data or the like, about 40 points are marked in the scanning range, each point is measured for about 0.75 seconds, and scanning processing is performed for about 30 seconds in total (hereinafter, this measurement condition is referred to as "typical condition").
However, the measurement value (intensity) at each measurement point forming the profile includes a statistical variation (error), and the shape of the profile obtained in the peak search may change due to the statistical variation. When the shape of the contour changes, the peak position may be erroneously determined, and when the spectral wavelength that deviates from the true peak position is measured, an error occurs in the measured intensity, and an error occurs in the concentration measurement result.
Fig. 3 is a graph showing in detail the signal intensity in the vicinity of the peak position of the profile shown in fig. 2. Referring to fig. 3, the signal strength at five points in total with respect to the peak position and its two points before and after is shown enlarged here.
Statistically, the error in intensity (the count of characteristic X-rays obtained by the detector) is used
And (4) showing. In this example, when the intensity of the peak position is approximately 10000 counts, the measurement value having an intensity of 10000 counts includes an error of 100 counts in a standard deviation of 1 σ, and has a deviation of the intensity of about 1%. Therefore, even a wavelength position whose intensity is lower than the original peak by about 1% may be determined as the peak position.
In the illustrated example, the center point is the peak position, but the true peak position may exist at any one of the two points on the left or in the vicinity thereof, and an error in the peak position may cause an error in the quantitative analysis.
In order to reduce such errors caused by statistical variations, a method of increasing the measurement time (increasing the count value) at each measurement point is effective. However, if the measurement time of each measurement point needs to be doubled in order to halve the error caused by the above statistical variation, the time required to perform the peak search increases significantly. Although it is also conceivable to narrow the scanning range by an amount corresponding to the measurement time extension, there is a possibility that a peak is not included in the scanning range and the peak search fails.
Therefore, in the EPMA 100 according to the present embodiment, the wavelength scanning performed in the peak search is performed in two stages of "coarse scanning" and "fine scanning". The purpose of the coarse sweep is to determine the approximate peak position (hypothetical peak position) in a short time. The jog scan is a scan performed subsequent to the coarse scan, and aims to narrow a scan range based on a virtual peak position obtained in the coarse scan, thereby determining a peak position with high accuracy. Thus, a high-precision peak search can be realized without increasing the processing time.
Fig. 4 is a diagram showing a scanning range of the jog scan. Referring to fig. 4, in the coarse scanning performed before the fine scanning, a scanning range (for example, several times the half width of the estimated contour) is set to be approximately the same as the above-described typical condition. Then, a virtual peak position (spectral wavelength λ c) is determined from the profile obtained by the coarse scanning, and in the fine scanning performed subsequent to the coarse scanning, a peak search is performed with high accuracy in a scanning range including the virtual peak position and narrower than the scanning range of the coarse scanning.
Fig. 5 is a diagram showing an example of the measurement conditions of the coarse movement scan (coarse movement conditions) and the measurement conditions of the fine movement scan (fine movement conditions). Referring to fig. 5, in the coarse scanning, for example, 40 dots are marked in the scanning range as in the above-described typical condition. Then, the measurement was performed for 0.25 seconds one by one at each measurement point, and the scanning process was performed for 10 seconds in total.
On the other hand, in the fine scanning performed subsequent to the coarse scanning, for example, the measurement is performed for 3.0 seconds one by one at each of five measurement points centered on the virtual peak position specified in the coarse scanning, and the scanning processing is performed for 15 seconds in total.
Therefore, in this example, the total processing time for the coarse scanning and the fine scanning is 25 seconds. In addition, under typical conditions shown as a reference example, 40 points are marked in the scanning range, and measurement is performed for 0.75 seconds one by one at each point, thus totaling a processing time of 30 seconds. As described above, in the EPMA 100 according to the present embodiment, the two-stage scanning process of the rough scan and the fine scan is performed in the same processing time as the typical conditions. In addition, since each measurement point is measured for 3 seconds in the micro scanning, an error due to a statistical variation can be halved as compared with a case where measurement is performed under a typical condition in which measurement is performed for 0.75 seconds for each measurement point.
Fig. 6 is a graph showing the signal intensity in the vicinity of the peak position. Referring to fig. 6, circular marks represent the respective measurement values in the coarse movement scan, and triangular marks represent the respective measurement values in the fine movement scan. In the coarse scanning, the measurement time at each measurement point is short, and the measurement value has a large variation, but an approximate peak profile is obtained. In this example, the peak position of the profile obtained by the coarse scanning is the wavelength λ c.
On the other hand, in the jog scan, since the measurement time of each measurement point is long, the deviation of the measurement value is small, and in this example, the peak position of the profile obtained by the jog scan is a wavelength shorter than the wavelength λ c by an amount corresponding to one measurement interval. The contour obtained by the micro-sweep becomes a sharp contour which is convex upward, and the peak position can be determined with high accuracy.
Fig. 7 is a flowchart showing an example of a procedure of quantitative analysis using the EPMA 100 according to the present embodiment. Referring to fig. 7, first, composition conditions (weight percentage of the target element in the standard sample, etc.) of the standard sample whose composition is known are input (step S10). The composition condition may be input from the operation unit 13 by the user, or may be stored in advance in a memory based on the result of a previous evaluation test or the like.
Next, the data processing unit 11 performs a standard sample measurement process of measuring characteristic X-rays corresponding to the target element on the standard sample to which the composition condition is input (step S20). Details of the measurement process performed here will be described later.
In the standard sample measurement processing of step S20, the peak intensity of the characteristic X-ray corresponding to the object element is measured for the standard sample. Then, the data processing section 11 corrects the measured intensity of the characteristic X-ray in consideration of the composition condition input in step S10, thereby calculating a standard sensitivity with respect to the object element (step S30).
Next, the data processing unit 11 performs target sample measurement processing for measuring characteristic X-rays corresponding to the target element on an unknown sample including the target element (hereinafter referred to as "target sample") (step S40). The procedure of the measurement process performed here is the same as the standard sample measurement process of step S20, and will be described in detail later.
In the target sample measurement processing of step S40, the peak intensity of the characteristic X-ray corresponding to the target element is measured for the target sample. Next, the data processing unit 11 calculates a ratio (intensity ratio) between the peak intensity of the target sample calculated in step S40 and the peak intensity of the standard sample calculated in step S20 (step S50). Then, the data processing unit 11 calculates the concentration of the target element in the target sample based on the intensity ratio calculated in step S50 (step S60).
Fig. 8 is a flowchart showing an example of the procedure of the measurement processing executed in step S20 and step S40 of fig. 7. Referring to fig. 8, first, an analysis position on the sample is set (step S110). Next, irradiation conditions for irradiating the electron beam with the irradiation device (the electron gun 1, the deflection yoke 2, and the objective lens 3) are set (step S120). Here, the irradiation conditions in the standard sample measurement processing of step S20 in fig. 7 and the irradiation conditions in the target sample measurement processing of step S40 are set to the same conditions.
Next, the object element is specified (step S130). The user can specify the object element from the operation unit 13, and can also specify a plurality of object elements. After the target element is specified, the data processing unit 11 sets a range of peak positions (wavelengths) of the characteristic X-rays corresponding to the specified target element, and sets a spectroscopic crystal suitable for the target element (wavelength of the characteristic X-rays corresponding to the target element) (step S140). Further, the relationship of the element with the range of peak positions (wavelengths) of the characteristic X-rays and the relationship of the element (wavelength of the characteristic X-ray corresponding to the element) with the spectroscopic crystal are determined in advance and stored in the memory.
Then, when the above various settings are completed, the data processing section 11 executes a peak search process (step S150).
Fig. 9 is a flowchart showing an example of the procedure of the peak search processing executed in step S150 in fig. 8. Referring to fig. 9, the data processing unit 11 sets a range of coarse scanning (step S210). This range can be set to, for example, about several times the half width of a contour expected from past data or the like.
Next, the data processing unit 11 determines the measurement position and the measurement condition of the coarse scanning (step S220). In this example, according to the coarse movement condition shown in fig. 5, the measurement position (spectral wavelength) is determined so that 40 points are marked on the scanning range set in step S210, and the measurement time at each measurement point is set to 0.25 seconds. Then, the data processing unit 11 executes coarse scanning processing in accordance with the set measurement position and measurement condition (step S230).
When the coarse scanning process is performed, the data processing section 11 detects a virtual peak position from the profile obtained by the coarse scanning (step S240). Specifically, the data processing unit 11 detects a position (wavelength) at which the intensity is maximum among the measurement positions (wavelengths) of the 40 points that have been measured as a virtual peak position.
When the virtual peak position is detected, the data processing unit 11 determines the measurement position and the measurement condition of the fine movement scan (step S250). In this example, according to the inching condition shown in fig. 5, five points before and after the virtual peak position detected in step S240 is set as the measurement position, and the measurement time at each measurement point is set to 3.0 seconds. Then, the data processing unit 11 executes the fine scanning process according to the determined measurement position and measurement condition (step S260).
When the jog scan process is executed, the data processing portion 11 detects a peak position from the profile in the vicinity of the peak obtained by the jog scan (step S270). Specifically, the position (wavelength) at which the intensity is maximum among the measurement positions (wavelengths) of the five points at which the measurement is performed is detected as the peak position.
In the above, the peak search process is executed for each of the measurement of the standard sample (step S20 in fig. 7) and the measurement of the target sample (step S40), but the peak position specified in the measurement of the standard sample may be used for the measurement of the target sample. However, in the measurement of the standard sample and the measurement of the target sample, there may occur a shift in wavelength depending on reproducibility of the mechanical operation of the spectroscope (operation of the goniometer), a shift in wavelength depending on the chemical bonding state of the element, and the like, and therefore, as described above, it is preferable to perform the peak search in the measurement of the standard sample and the measurement of the target sample, respectively.
In this way, in this embodiment, the scanning process at the time of peak search is performed in two stages of the coarse movement scanning and the fine movement scanning. In the coarse scanning, the processing time is short although the accuracy is low because the measurement time at each measurement point is short. In the fine scanning following the coarse scanning, the measurement time at each measurement point is longer than that in the coarse scanning, but the scanning range is narrowed based on the virtual peak position based on the coarse scanning, and therefore, highly accurate measurement can be performed in a short time without missing the peak. Therefore, according to this embodiment, it is possible to realize a high-precision peak search without increasing the processing time.
[ modified examples ]
In the above-described embodiment, the position (wavelength) at which the intensity is the greatest among the measurement positions (wavelengths) at five points that are measured in the fine movement scan is detected as the peak position, but in order to detect the peak position with higher accuracy, the peak position may be estimated by smoothing the measurement result of the fine movement scan.
Fig. 10 is a graph showing the signal intensity in the vicinity of the peak position. Referring to fig. 10, circular marks indicate the measurement values of the respective measurement points in the micro-sweep. The curve L is a curve obtained by approximating the measurement result of the jog scan with a curve (e.g., a quadratic function). Further, the position (wavelength) at which the curve L is maximum may be detected as the peak position. This enables the peak position to be detected with higher accuracy.
Fig. 11 is a flowchart showing an example of the procedure of the peak search processing in the modification. This flowchart corresponds to the flowchart shown in fig. 9. Referring to fig. 11, the processing of steps S310 to S360 and S380 is the same as the processing of steps S210 to S270 of fig. 9, respectively.
In this modification, when the jog scan process is executed in step S360, the data processing unit 11 executes a smoothing process of smoothing the contour (five measurement points) obtained by the jog scan (step S370). Specifically, the data processing unit 11 performs curve approximation (for example, approximation using a quadratic function) on five points measured in the fine scanning, and generates a smoothed contour.
Then, in step S380, the peak position is detected from the smoothed profile obtained in step S370.
According to this modification, the peak position can be detected with higher accuracy by smoothing the contour obtained by the micro-sweep.
In the above embodiment, the processing time of the coarse movement scan is shortened by shortening the measurement time of each measurement point in the coarse movement scan as compared with the typical condition, but as another modification, the processing time of the coarse movement scan may be shortened by reducing the number of measurement points in the coarse movement scan.
Fig. 12 is a diagram showing another example of the rough movement condition and the fine movement condition. This fig. 12 corresponds to fig. 5. Referring to fig. 12, in the coarse scanning, a scanning range (about a few times the half width of the outline) is set to be approximately the same as that in the typical condition, and 20 points (half of the typical condition) are marked in the scanning range. Then, as in the typical condition, the measurement was performed for 0.75 seconds one by one at each measurement point, and the scanning process was performed for 15 seconds in total.
On the other hand, in the fine scanning, for example, five points each including three points before and after the center of the virtual peak position specified by the coarse scanning and each intermediate point between two adjacent points among the three points are set as the measurement positions. Then, measurements were performed for 3 seconds one by one at each measurement point, and scanning processing was performed for 15 seconds in total. This inching condition is the same as the inching condition shown in fig. 5.
In this example, the total processing time of the coarse scanning and the fine scanning is 30 seconds. Therefore, according to this modification, the scanning process in two stages, coarse scanning and fine scanning, is also performed in the same processing time as the typical conditions. In addition, since each measurement point is measured for 3 seconds in the micro scanning, an error due to a statistical variation can be halved compared to the case of performing measurement under typical conditions.
In the above example, the measurement time of each measurement point in the coarse movement scan is the same as the measurement time in the typical condition (0.75 seconds), but the processing time can be further shortened by also shortening the measurement time of each measurement point.
[ means ]
It will be understood by those skilled in the art that the above-described exemplary embodiments and modifications thereof are specific examples of the following manner.
An X-ray analysis apparatus according to a (first aspect) includes: a wavelength dispersion type optical splitter; and a processing device configured to execute a peak search process of detecting a peak position of a spectrum of the characteristic X-ray separated using the spectroscope. The peak search processing includes a scanning process in which the spectral profile is acquired by measuring the characteristic X-rays one by one for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays changes at predetermined interval steps. The scanning process includes a first scanning process (coarse scanning) and a second scanning process (fine scanning). The first scanning process acquires a profile for a first wavelength range. The second scanning process acquires a profile regarding a second wavelength range that includes a peak position of the profile acquired by the first scanning process and is narrower than the first wavelength range. The first predetermined time, which is the predetermined time for the first scanning process, is shorter than the second predetermined time, which is the predetermined time for the second scanning process.
In the X-ray analysis apparatus according to the first aspect, the scanning process is performed in two stages as described above. Since the measurement time of each measurement point in the first scanning process (coarse scanning) is short, the processing time is short although the accuracy is low. The measurement time at each measurement point in the second scanning process (fine scanning) following the first scanning process (coarse scanning) is longer than the measurement time in the first scanning process, but the scanning range is narrowed to the second wavelength range, so that highly accurate measurement can be performed in a short time without missing peaks. Therefore, according to the X-ray analysis apparatus, it is possible to realize a high-precision peak search without increasing the processing time.
(second item) in the X-ray analysis device according to the first item, the processing device may be configured to further execute a smoothing process of smoothing the contour acquired by the second scanning process (micro-scanning).
According to the X-ray analysis device of the second aspect, the contour acquired by the second scanning process is smoothed, whereby the peak position can be detected with higher accuracy.
(third item) in the X-ray analysis device according to the first or second item, a first predetermined interval, which is a predetermined interval in the first scanning process (coarse scanning), may be larger than a second predetermined interval, which is a predetermined interval in the second scanning process (fine scanning).
According to the X-ray analysis apparatus of the third aspect, the processing time required for performing the first scanning process can be further shortened.
(fourth item) in the X-ray analysis device according to any one of the first to third items, the processing device may perform quantitative analysis using the intensity of characteristic X-rays at the peak position of the profile acquired by the second scanning process (micro-scanning).
According to the X-ray analysis apparatus of the fourth aspect, the peak position can be detected with high accuracy, and therefore the accuracy of quantitative analysis is improved.
(fifth item) in the X-ray analysis device according to any one of the first to fourth items, the X-ray analysis device may further include an irradiation device configured to irradiate the sample with an electron beam.
According to the X-ray analysis apparatus of the fifth aspect, in the EPMA, the peak search with high accuracy can be realized without increasing the processing time.
In addition, the peak search method according to another aspect is a peak search method for detecting a peak position of a spectrum of a characteristic X-ray separated by using a wavelength dispersion type spectrometer, and includes a first step and a second step. In the first step, the profile of the spectrum in the first wavelength range is acquired by measuring the characteristic X-rays one by one for a first predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays changes at predetermined interval steps. In the second step, the spectrometer is operated so as to change the wavelength of the characteristic X-rays at predetermined intervals, and the characteristic X-rays are measured one by one for a second predetermined time, thereby acquiring a profile of the spectrum in a second wavelength range which includes the peak position of the profile acquired in the first step and is narrower than the first wavelength range. The first predetermined time in the first step is shorter than the second predetermined time in the second step.
According to the peak search method described in the sixth item, highly accurate peak search can be realized without increasing the processing time.
The presently disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.
Claims (6)
1. An X-ray analysis apparatus includes:
a wavelength dispersion type optical splitter; and
a processing device configured to execute a peak search process of detecting a peak position of a spectrum of the characteristic X-ray separated by the beam splitter,
wherein the peak search processing includes a scanning processing of measuring the characteristic X-rays one by one for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays is changed at predetermined interval steps to acquire the profile of the spectrum,
wherein the scanning process includes the following processes:
a first scanning process of acquiring the profile with respect to a first wavelength range; and
a second scanning process of acquiring the profile with respect to a second wavelength range that includes a peak position of the profile acquired by the first scanning process and is narrower than the first wavelength range,
wherein a first predetermined time, which is the predetermined time of the first scanning process, is shorter than a second predetermined time, which is the predetermined time of the second scanning process.
2. The X-ray analysis apparatus according to claim 1,
the processing device is configured to further execute a smoothing process of smoothing the contour acquired by the second scanning process.
3. The X-ray analysis apparatus according to claim 1 or 2,
the first predetermined interval, which is the predetermined interval in the first scanning process, is larger than the second predetermined interval, which is the predetermined interval in the second scanning process.
4. The X-ray analysis apparatus according to claim 1 or 2,
the processing device quantitatively analyzes the sample that generates the characteristic X-ray using the intensity of the characteristic X-ray at the peak position of the profile acquired by the second scanning process.
5. The X-ray analysis apparatus according to claim 1 or 2,
the apparatus further includes an irradiation device configured to irradiate the sample with an electron beam.
6. A peak search method for detecting a peak position of a spectrum of a characteristic X-ray separated using a wavelength dispersion type optical splitter, comprising the steps of:
a first step of measuring the characteristic X-rays one by one for a first predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays is changed at predetermined interval steps, thereby acquiring a profile of the spectrum in a first wavelength range; and
a second step of measuring the characteristic X-rays one by one for a second predetermined time while operating the spectroscope so that the wavelength of the characteristic X-rays is changed at the predetermined interval step, thereby acquiring the profile for a second wavelength range that includes the peak position of the profile acquired in the first step and is narrower than the first wavelength range,
the first predetermined time is shorter than the second predetermined time.
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| JP2019105654A JP2020201038A (en) | 2019-06-05 | 2019-06-05 | X-ray analyzer and peak search method |
| JP2019-105654 | 2019-06-05 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1033538A (en) * | 1987-12-14 | 1989-06-28 | 株式会社岛津制作所 | Spectrophotometric Wavelength scanning method |
| JPH0831367A (en) * | 1994-07-12 | 1996-02-02 | Jeol Ltd | Peak searching method for spectrograph |
| CN102680097A (en) * | 2011-03-10 | 2012-09-19 | 大塚电子株式会社 | Spectral characteristic measurement method and spectral characteristic measurement apparatus |
| CN106596613A (en) * | 2017-02-16 | 2017-04-26 | 武汉泛洲中越合金有限公司 | Method for detecting element content by using scanning channel of X-ray fluorescence spectrometer |
| CN109196340A (en) * | 2016-09-30 | 2019-01-11 | 株式会社理学 | Wavelength-dispersion type fluorescent x-ray analyzer and the fluorescent x-ray analysis method for using it |
-
2019
- 2019-06-05 JP JP2019105654A patent/JP2020201038A/en active Pending
-
2020
- 2020-04-30 CN CN202010362698.7A patent/CN112051289A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1033538A (en) * | 1987-12-14 | 1989-06-28 | 株式会社岛津制作所 | Spectrophotometric Wavelength scanning method |
| JPH0831367A (en) * | 1994-07-12 | 1996-02-02 | Jeol Ltd | Peak searching method for spectrograph |
| CN102680097A (en) * | 2011-03-10 | 2012-09-19 | 大塚电子株式会社 | Spectral characteristic measurement method and spectral characteristic measurement apparatus |
| CN109196340A (en) * | 2016-09-30 | 2019-01-11 | 株式会社理学 | Wavelength-dispersion type fluorescent x-ray analyzer and the fluorescent x-ray analysis method for using it |
| CN106596613A (en) * | 2017-02-16 | 2017-04-26 | 武汉泛洲中越合金有限公司 | Method for detecting element content by using scanning channel of X-ray fluorescence spectrometer |
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| JP2020201038A (en) | 2020-12-17 |
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