JP6256152B2 - X-ray measuring device - Google Patents

Description

  The present invention relates to an X-ray measurement apparatus (X-ray analysis apparatus) such as a fluorescent X-ray analysis apparatus and an X-ray diffraction apparatus, and more specifically, a large number of X-ray detection elements are arranged in one or two dimensions. The present invention relates to an X-ray measuring apparatus that detects an X-ray intensity profile using an X-ray detector array (array type X-ray detector).

  Various types of X-ray measuring devices (analyzers) using X-ray detectors are used. For example, an X-ray diffractometer irradiates a powder sample or the like with characteristic X-rays from an X-ray source, and detects diffracted X-rays emitted from the powder sample or the like at each diffraction angle by an X-ray detector mounted on a goniometer. (See Patent Document 1). Thereby, the qualitative and quantitative analysis of the crystal component contained in a powder sample etc. is performed.

  The wavelength-dispersion X-ray fluorescence analyzer irradiates a sample with X-rays from an X-ray source, separates the fluorescent X-rays generated from the sample with a spectroscopic crystal, and detects X-rays of the dispersed fluorescent X-rays It detects for every wavelength with an instrument (refer patent document 2). Thereby, the quantitative and qualitative analysis of the element component which comprises a sample is performed.

  In recent years, an X-ray detector array (also referred to as a line sensor) in which a large number of X-ray detection elements (for example, 1280 elements) are linearly arranged in order to shorten the measurement time is included in these X-ray measurement apparatuses. An apparatus that simultaneously arranges X-ray intensity distributions in a range (region) that can be measured by each detection element of an X-ray detector array, which is arranged at a position where an X-ray signal from a measurement target is detected, has also been developed.

  By the way, when X-ray detection is conventionally performed, an X-ray detector is placed at a detection position, detected at the same position over a predetermined integration time (for example, 10 seconds), and signals acquired during that time are integrated. In general, a sufficient signal strength can be obtained. In addition, even in an X-ray measuring apparatus using an X-ray detector array, when acquiring intensity distribution data with sufficiently strong intensity, a function of integrating X-ray signals at respective detection positions for each detection element. Is provided.

Japanese Patent Laid-Open No. 10-185844 JP2012-242285A

  The X-ray detector array has a large number of detector elements arranged side by side, and it goes without saying that all detector elements are preferably normal elements that can be measured, but there are no defective elements at all. It is quite difficult to manufacture a simple X-ray detector array. Therefore, an X-ray detector array including a few defective elements may be inevitably used as a non-defective product for the convenience of the product yield. X-ray intensity distribution data may have to be acquired. Therefore, as shown in FIG. 5, when X-ray intensity distribution data is detected by an X-ray detector array including a defective element, the accumulated X-ray signal is missing data with a signal intensity of zero at the position of the defective element. It has become. In such a case, the intensity data at the position of the defective element is calculated by interpolation processing from the signal intensity of a normal element adjacent to the defective element.

  However, when the intensity data at the position of the defective element is obtained by interpolation processing, when the peak of the X-ray intensity signal exists in the vicinity of the position of the defective element, the normal element adjacent to both sides of the defective element with a slight difference in the peak position. Signal intensity greatly varies, and the interpolation data obtained by the interpolation process varies greatly. Therefore, in the qualitative analysis for obtaining the peak position and the quantitative analysis based on the peak area ratio, it is easy to produce a large error in the calculation result only by using the interpolation processing that has been conventionally performed, and it is difficult to obtain preferable interpolation data. is there.

  For example, when performing a quantitative analysis from the area ratio of the corresponding signal peaks by two measurements of a known sample (standard sample) and an unknown sample, the known sample is set at the sample mounting position and the first measurement is performed. Thereafter, the measurement sample is replaced with an unknown sample, and the second measurement is performed. However, it is inevitable that the mounting position of the measurement sample slightly changes during sample replacement. As a result, the peak position of the detected signal peak also changes slightly, so when the signal peak position is in the vicinity of the defective element and the same interpolation processing is performed as before, the sample mounting position A small error would cause a large error.

  This problem appears more remarkably when a plurality of defective elements continue. However, if the number of consecutive defective elements is too large, it is determined that the detector array is defective. Therefore, it is practically assumed that a maximum of about five defective elements are continuous.

  Therefore, the present invention detects the X-ray intensity distribution by the X-ray detector array in which the defective element exists, by a method different from the conventional method, so that the peak position of the X-ray signal exists in the vicinity of the defective element. Even so, an object of the present invention is to provide an X-ray measuring apparatus capable of measuring the peak top position in qualitative analysis and the area ratio in quantitative analysis without problems.

  In addition, the present invention takes into consideration the case where a defective element is generated later, and further, the X-ray detector can be stably provided without worrying about whether or not the defective element exists. An object of the present invention is to provide an X-ray measurement apparatus capable of measuring (analyzing) an X-ray intensity distribution using an array.

X-ray measuring apparatus of the present invention made to solve the above problems, an X-ray detector array X-ray detector elements are arranged one-dimensionally or two-dimensionally, detect for detecting X-ray signals from the measurement target The X-ray signal is arranged at a position, and the X-ray signal is integrated at the detection position over a predetermined integration time, and the X-ray signal integrated by the X-ray detection elements during the integration time is detected as an intensity distribution signal. An X- ray measurement apparatus, wherein when there is a missing portion in the X-ray detection element, an interpolation processing unit that performs an interpolation process based on detection signal data on both sides sandwiching the missing portion, and the X-ray at the detection position A swinging mechanism that swings the X-ray detector array with a swinging width that exceeds the width of the missing portion along the arrangement direction of the detecting elements, and a swinging control that swings the swinging mechanism during the integration time. And so on.

  According to the present invention, when detecting an X-ray signal including a peak signal, the X-ray detector array is swung along the arrangement direction of the detection elements during the integration time. Then, not only a part of the detection element group (referred to as element group A) existing in the peak irradiation range (region) where the X-ray peak signal is irradiated in the stationary state, but also the peak irradiation range due to oscillation. A part of the peak signal is also irradiated during the integration time to a nearby detection element group (referred to as element group B) that temporarily enters the element.

In other words, the X-ray dose that is originally counted only by the element group A during the integration time is counted so as to be equalized between the element groups A and B obtained by adding the neighboring element group B to the element group A by swinging. Will be.
Assuming that all the elements in the element groups A and B are normal elements, it is assumed that the element group has been swung a sufficient number of times during the integration time (at least 5 times or more, for example, 10 times during the integration time). Then, when the peak signal waveform A after the integration time detected in the stationary state is compared with the detection signal peak signal waveform B after the integration time detected in the oscillation state, as shown in FIG. As a result, the peak signal waveform B becomes smaller than the peak signal waveform A with respect to the peak height, and the peak width is widened to become a broad waveform, so that the resolution is deteriorated. However, the peak top position obtained by the qualitative analysis and the peak area ratio obtained by the quantitative analysis are almost the same as the peak signal waveform A in the stationary state even when obtained from the detection data averaged over the entire element groups A and B. Can be determined with accuracy.

By the way, when a defective element is included in a part of the element groups A and B described above, if it swings with a peristaltic width (specifically, a width corresponding to five elements) exceeding a width where a signal due to the defective element is missing. In the stationary state, a missing data portion occurs in a part of the peak signal waveform A, and in a rocking state, a peak signal waveform in which a missing data portion occurs in a part of the peak signal waveform B is obtained.
With respect to the error of the peak top position and peak area ratio obtained by performing the interpolation process for these missing portions, the error in the peak signal waveform B, which is a leveled signal, is the peak signal waveform A. Therefore, it is possible to measure with a smaller error when the detection is performed while being perturbed.

According to the present invention, when the intensity distribution measurement is performed with the X-ray detector array including the defective element, the resolution is deteriorated by peristating the detector array, but the peak top position is detected in the qualitative analysis. The detection of the peak area ratio in the quantitative analysis can be obtained more accurately and easily than when detecting without swinging.
In addition, even if an X-ray detector array does not include a defective element, the above-described peak position and peak area ratio can be obtained sufficiently accurately by peristating, so that it can be perturbed regardless of the presence or absence of a defective element. By performing detection, the measurer can accurately measure the peak position and the peak area ratio without being aware of the presence of the defective element.

In the above invention, the swing control unit may control the swing mechanism so that the integral swing is performed in accordance with the accumulated time.
If the number of perturbations during the integration time is many (5 or more), the influence of the amount of signal accumulated in one perturbation on the entire signal is sufficiently small, so even if one or less perturbations are ignored Although the influence is small, if the number of times of perturbation is a small number (less than 5), the influence of the signal amount in one or less perturbations on the entire signal cannot be ignored.
However, as long as the number of peristaltic movements during the integration time is controlled to be an integer number, the X-rays radiated to each detection element can be emitted without being biased regardless of the number of peristaltic movements. Even if there is little (for example, 1 to 2 times), an accurate measurement becomes possible.

In the above invention, the X-ray measuring device is an X-ray diffractometer provided with a goniometer, and the X-ray detector array is provided with a rotation drive mechanism for rotating about the rotation center of the goniometer, and a swing mechanism The rotary drive mechanism may also be used.
According to the present invention, there is provided a control system (control program) for swinging during the integration time by swinging the detector array using the goniometer originally provided in the X-ray diffraction apparatus and its rotational drive mechanism. The present invention can be realized in an X-ray diffractometer only by adding.

In the above invention, the X-ray measurement apparatus may be an X-ray fluorescence analyzer that detects an X-ray signal of fluorescent X-rays dispersed in wavelength by a spectroscopic element using an X-ray detector array.
According to the present invention, the present invention can be realized in a fluorescent X-ray analyzer.

1 is a schematic configuration diagram of an X-ray diffraction apparatus according to an embodiment of the present invention. The figure which shows the signal of the peak vicinity in the case of calculating | requiring a peak top position by qualitative analysis. The figure which shows the signal of the peak vicinity in the case of calculating | requiring a peak area ratio by quantitative analysis. The schematic block diagram of the fluorescent X-ray-analysis apparatus which is other one Embodiment of this invention. The figure which shows the signal at the time of X-ray intensity distribution data detection in the X-ray detector array containing a defective element. The figure which shows an example of the peak waveform when all the elements of a X-ray detector array are normal elements, and the said array is made into a stationary state or a peristaltic state, and a signal is detected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a schematic configuration diagram of an X-ray diffraction apparatus according to an embodiment of the present invention.
The X-ray diffraction apparatus 1 includes an X-ray source 11, a slit 12, a line sensor (X-ray detector array) 13, a goniometer 30, and a control unit (computer) 20 that controls the entire X-ray diffraction apparatus 1. Is provided.

In the line sensor 13, N (for example, 1280) detection elements (semiconductor elements) are arranged one-dimensionally. Then, the X-ray intensity I _n (detection element number n = 1, 2,..., N) detected by each detection element over a predetermined integration time is output to the control unit 20. ing. The integration time may be set to such an extent that a peak signal with sufficient intensity can be obtained according to the sample. For example, the integration time is set to about 10 to 30 seconds.
The line sensor 13 is mounted on the 2θ axis of the goniometer 30 and the measurement sample S is mounted on the θ axis of the goniometer 30. Each is rotated about a central axis by an attached rotary drive mechanism (not shown). In this embodiment, the line sensor 13 can be peristally moved at the detection position using the rotational drive mechanism.

  A computer constituting the control unit 20 includes a CPU 21, an input device 22, and a display device 23, and controls the entire X-ray diffraction apparatus 1. Among the controls performed by the CPU 21, functions related to the present invention will be described as a block. An X-ray source control unit 21a, a signal acquisition unit 21b, an image display control unit 21c, a rotation control unit 21d, and an interpolation processing unit 21e. And a peristaltic control unit 21f.

The X-ray source control unit 21 a performs control to emit characteristic X-rays from the X-ray source 11.
Signal acquisition unit 21b, during the time integration set by the input device 22 (e.g., 10 seconds), the control to get by integrating each of the N X-ray intensity signal I _n that each detector element detects the line sensor 13 I do.
Image display control unit 21c performs control to image display of the X-ray intensity signal I _n acquired over integration time by each detector element as the intensity distribution.
The rotation control unit 21d performs control to rotate the goniometer 30 so that the sample S and the line sensor 13 can perform measurement while maintaining a θ-2θ interlocking relationship during diffraction measurement.
When there is a missing portion of the detection signal due to the presence of a defective element, the interpolation processing unit 21e performs interpolation processing based on the detection signal data on both sides sandwiching the missing portion.

  The peristaltic control unit 21f is a component that performs control necessary to realize a new function according to the present invention, and controls the swing of the line sensor 13 by driving the rotational drive mechanism of the goniometer 30 during the integration time. Do. This swing is controlled so that the line sensor 13 swings an integral number of times during the integration time. For example, the control is performed so that one or two oscillations, which are integral times in an integrated time of 10 seconds, or many perturbations (reciprocating) five times or more are performed. If the number of oscillations is 5 times or more, preferably 10 times or more, the influence on the entire signal by one or less oscillations is sufficiently small. Therefore, it is necessary to accurately control the number of oscillations to be an integer number of oscillations. Disappear. In the present embodiment, the rocking is performed about 10 times with an integration time of 10 seconds.

  Next, the measurement operation will be described. In general, the X-ray diffractometer 1 is provided with several measurement modes depending on the measurement contents. Specifically, the line sensor 13 is continuously rotated and scanned in order to perform diffraction measurement in a wide angle range, or measurement is performed by scanning intermittently for each angular range width that can be measured by the line sensor 13. A “scan mode” is provided.

  Further, when measuring a sample or the like whose angle range for detecting the peak signal is known and the angle range to be detected may be narrow, diffraction measurement can be performed without moving the line sensor 13, A “fixed measurement mode” (one-shot mode) is also provided in which the line sensor 13 is set at a detection position in a desired angle range and is fixed at the detection position during the integration time. The measurement mode can be selected by an input operation from the input device 22.

  Since the present invention has one object of eliminating the adverse effects due to the presence of defective elements using this “fixed measurement mode”, the following will explain the “fixed measurement mode” and execute the present invention. This will be described in comparison with the “oscillation measurement mode”.

  In the “fixed measurement mode”, when the line sensor 13 is fixed at the detection position and measured during the integration time, the intensity distribution of the X-ray signal can be obtained with higher resolution (than the “swing measurement mode” described later). it can. However, if a defective element is included in a part of the X-ray detection elements of the line sensor 13, a signal corresponding to the position of the defective element is lost. In this case, interpolation processing is performed by the interpolation processing unit 20e. Will be done.

  FIG. 2 is a diagram showing a signal in the vicinity of the peak when the peak top position is obtained by qualitative analysis. FIG. 2A is an X-ray signal in the “fixed measurement mode” measurement, which is detected when a defective element is present. It is a schematic diagram of a signal waveform showing a missing signal profile (thick solid line portion) and an interpolation profile (thin solid line portion) obtained by interpolation processing. The original peak profile (dotted line portion), that is, the peak profile when there is no defective element is also shown. FIG. 2 shows a state in which a peak position happens to be near the position of the defective element.

In this case, in the “fixed measurement mode”, a high-resolution peak is obtained, and as a result, the signal height near the peak is sufficiently high and changes sharply. Therefore, the interpolation profile in the presence of a defective element is to be interpolated at a sharply changing position. If there is a slight positional deviation in the peak width direction, the normal element position P (adjacent to the defective element) is detected. _1, the variation of the signal level of the _{P 2} increases. Therefore, even if the peak top position is calculated by Gaussian fitting or the like using an interpolation profile obtained using a signal with large fluctuations, the peak top position is likely to fluctuate from the original position and has low reproducibility. Therefore, the reliability of the obtained peak position is low, and when the peak position is detected and the qualitative analysis is performed, a determination error in the qualitative analysis is likely to occur.

  In contrast, in the X-ray diffraction apparatus 1, in addition to the “fixed measurement mode”, a “swing measurement mode” for performing the same measurement while swinging the line sensor 13 at the detection position by the swing control unit 21f is added. Has been. That is, by selecting the “swing measurement mode” with the input device 22, control is performed to acquire the X-ray signal while swinging the line sensor 13 at the detection position during the integration time.

FIG. 2B shows a missing signal profile (thick solid line portion) detected when a defective element is present in the X-ray peak signal during the “oscillation measurement mode” measurement, and an interpolation profile (thin solid line portion) obtained by interpolation processing. It is the schematic diagram of the signal waveform which showed. The original peak profile (dotted line portion) is also shown in the same manner as in FIG.
As a result of the X-ray signal being leveled by swinging, the missing signal profile has a height near the peak center that is lower than the original peak height, and the base of the peak is higher than the original peak height. The peak signal waveform is broad as a whole. Therefore, the resolution is deteriorated compared to the “fixed measurement mode”.

However, in the “oscillation measurement mode”, the interpolation profile when there is a defective element is interpolated on the averaged peak waveform, and even if there is a positional deviation in the width direction of the peak (defective element) The fluctuations in the signal height of the normal element positions P ₁ and P ₂ (adjacent to) are small. Therefore, since the interpolation profile does not fluctuate so much, when the peak top position is calculated by Gaussian fitting or the like, the fluctuation value from the original position becomes small and the reproducibility is large. Therefore, the reliability of the obtained peak position is high, and when the peak position is detected and the qualitative analysis is performed, a determination error in the qualitative analysis hardly occurs.

FIG. 3 is a diagram showing a signal in the vicinity of a peak when a peak area ratio is obtained by quantitative analysis. FIG. 3A shows the missing signal profile (thick solid line portion) detected when a defective element is present in the X-ray peak signals of the standard sample S and the unknown sample U in the “fixed measurement mode” measurement, and is obtained by interpolation processing. It is a schematic diagram of a signal waveform showing an interpolation profile (thin solid line part), the upper side shows the measurement result of the standard sample S, and the lower side shows the measurement result of the unknown sample U after the sample replacement. The original peak profile (dotted line portion) is also shown.
In quantitative measurement, the peak position may be slightly shifted due to a change in the optical path caused by sample exchange. In the “fixed measurement mode” in which a steep peak shape is obtained by shifting the peak position, even when the same content is measured, the peak areas obtained by the interpolation process are likely to vary greatly.
On the other hand, FIG. 3B shows a missing signal profile (thick solid line portion) detected when a defective element is present in the X-ray peak signal in the “swing measurement mode” measurement, and an interpolation profile obtained by interpolation processing ( It is a schematic diagram of a signal waveform showing a thin solid line portion). The original peak profile (dotted line portion) is also shown in the same manner as in FIG.
As a result of the swinging, the X-ray signal is leveled, resulting in an overall broad peak signal waveform. Also in the peak area ratio in the quantitative measurement, the fluctuation is smaller than that in the “fixed measurement mode”, and the error of the quantitative value can be suppressed small.

Although the case where the present invention is implemented in the X-ray diffraction apparatus 1 has been described above, the present invention can be applied to other X-ray measurement apparatuses.
For example, FIG. 4 is a schematic configuration diagram showing a fluorescent X-ray analyzer 2 which is another embodiment of the present invention. The X-ray fluorescence analyzer 2 includes an X-ray source 41 that irradiates the sample S with X-rays, a slit 42 that allows the fluorescent X-rays generated from the sample S to pass through, and fluorescent X-rays that enter through the slit 42. A spectroscopic crystal 43 for spectroscopic analysis, and a line sensor 44 (X-ray detector array) for detecting the fluorescent X-rays dispersed for each wavelength by the spectroscopic crystal for each wavelength are arranged in one dimension. Yes.
In this fluorescent X-ray analysis apparatus 2, a swing mechanism 45 that swings the line sensor 44 in the arrangement direction of the detection elements is newly provided.

A control unit (computer) 50 that controls the entire apparatus of the X-ray fluorescence analyzer 2 includes a CPU 51, an input device 52, and a display device 53. Of the control performed by the CPU 51, the functions related to the present invention will be described as a block. An X-ray source control unit 51a, a signal acquisition unit 51b, an image display control unit 51c, an interpolation processing unit 51e, And a peristaltic control unit 51f.
Since these perform the same control as the X-ray source control unit 21a, the signal acquisition unit 21b, the image display control unit 21c, the interpolation processing unit 21e, and the peristaltic control unit 21f in the X-ray diffraction apparatus 1 described with reference to FIG. To do.

  In the fluorescent X-ray analyzer 2, measurement in the “peristalsis measurement mode” similar to that of the X-ray diffraction apparatus 1 is performed by the peristaltic mechanism 45 and peristaltic control unit 51 f. Therefore, when a defective element exists in a part of the line sensor 44, an interpolation process with a smaller error than that in the “fixed measurement mode” can be performed.

  In the above-described embodiment, a line sensor in which N detection elements are arranged one-dimensionally is used. However, an X-ray detector array in which (N × M) detection elements are arranged two-dimensionally is used. You may make it move to a dimension.

  The present invention can be used for an X-ray diffraction apparatus, a fluorescent X-ray analysis apparatus, an X-ray measurement apparatus, and the like.

1 X-ray diffractometer 2 X-ray fluorescence analyzer 11, 41 X-ray source 13, 44 Line sensor (X-ray detector array)
20, 50 Control unit 30 Goniometer (oscillation mechanism)
21f, 51f Peristaltic control unit

Claims (4)

An X-ray detector array in which X-ray detection elements are arranged one-dimensionally or two-dimensionally is arranged at a detection position for detecting an X-ray signal from a measurement target, and the X-ray signal is taken over a predetermined integration time. An X-ray measuring apparatus that integrates at a detection position and detects an X-ray signal integrated by each X-ray detection element during the integration time as an intensity distribution signal,
When there is a missing part in the X-ray detection element, an interpolation processing unit that performs an interpolation process based on detection signal data on both sides sandwiching the missing part;
A swinging mechanism that swings the X-ray detector array with a swinging width that exceeds the width of the missing portion along the arrangement direction of the X-ray detection elements at the detection position;
An X-ray measurement apparatus comprising: a swing control unit that swings the swing mechanism during the integration time.   The X-ray measurement apparatus according to claim 1, wherein the swing control unit controls the swing mechanism so that swing is performed an integral number of times in accordance with an integration time. The X-ray measuring device is an X-ray diffractometer provided with a goniometer, and the X-ray detector array is provided with a rotation drive mechanism for rotating around the rotation center of the goniometer,
The X-ray measurement apparatus according to claim 1, wherein the swing mechanism is also used as the rotation drive mechanism. 3. The X-ray analysis apparatus according to claim 1, wherein the X-ray measurement apparatus is an X-ray fluorescence analysis apparatus that detects, with the X-ray detector array, an X-ray signal of fluorescent X-rays wavelength-dispersed by a spectroscopic element. Measuring device.

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