JP3852102B2 - X-ray diffractometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray diffraction measurement method, and relates to background removal included in X-ray diffraction data.
[0002]
[Prior art]
Measurement data obtained by the X-ray diffractometer is obtained as a detected intensity with respect to an angle. Usually, the measurement data of the X-ray diffractometer includes a signal component based on the measurement sample and a background component caused by the optical system and measurement system of the X-ray diffractometer. Since this background becomes an error, the X-ray diffraction apparatus performs data correction signal processing for removing the background from the measurement data.
[0003]
Conventionally, a calculation process called a Sonnebelt method is known as signal processing for obtaining a background from measurement data. This Sonnebelt method repeats the process of selecting a predetermined number of measurement data for the measurement data obtained from the measurement object and selecting the smaller one of the intermediate values of the adjacent selection data and the measurement data multiple times. This is a method for obtaining a background curve.
[0004]
[Problems to be solved by the invention]
Usually, the background curve obtained by the Sonnebelt method depends on calculation parameters such as the number of selected measurement data and the number of repetitions, and the measurement data itself. Therefore, there is a problem that when the calculation parameter is changed or the measurement object is different, the shape and intensity level of the intensity curve with respect to the angle of the required background curve are different. Therefore, there is a problem that proper background data cannot be obtained depending on the measurement target.
[0005]
Therefore, the present invention aims to solve the above-described conventional problems and to provide an X-ray diffraction measurement method capable of performing appropriate background removal using appropriate background data that does not depend on the measurement target. .
[0006]
[Means for Solving the Problems]
The X-ray diffraction measurement method of the present invention uses background data intensity curves that do not depend on measurement data or calculation parameters, obtains background data that does not depend on the measurement object, and removes the background data obtained from the measurement data. By performing data correction, appropriate background removal that does not depend on the measurement target is performed.
[0007]
In order to remove the above data, the X-ray diffraction measurement method of the present invention obtains an intensity curve based on measurement data of a standard sample with respect to an intensity curve and an intensity level with respect to an angle constituting background data. Is obtained based on the measurement data of the sample to be measured, and the background data that is not dependent on the measurement target is obtained by adjusting the level of the intensity curve according to the intensity level, and the background data obtained from the measurement data of the X-ray diffraction measurement is removed. To correct the data.
[0008]
The intensity curve is a curve formed by determining the background intensity that does not originate from the measurement object of the standard sample for each angle, and connecting the measured data obtained by measuring the standard sample. This intensity curve is an apparatus-specific background attributed to the X-ray diffraction apparatus itself, and has information only on the shape of the background curve. In addition, the intensity level is an intensity level for the background other than the signal in the measurement data obtained by measuring the sample to be measured, and is a value depending on the measurement conditions.
[0009]
Therefore, by adjusting the level of the intensity curve according to the intensity level, the background content included in the measurement data to be measured can be obtained, and the signal component can be obtained by subtracting the background content from the measurement data. Can be taken out.
[0010]
According to the X-ray diffraction measurement method of the present invention, the intensity curve with respect to the angle of the background data is obtained by measuring a standard sample to obtain measurement data, and the background not resulting from the measurement target of the standard sample at each angle of the measurement data. Determine by selecting the minutes and splicing them together. Since the intensity curve based on this standard sample is unique to the X-ray diffractometer, it is not necessary to obtain it for each measurement, and the intensity curve obtained once can be used in common for each measurement data.
[0011]
A background intensity level based on measurement conditions is obtained from measurement data of a measurement object, and an intensity curve level obtained from a standard sample is determined based on the intensity level. As a result, a background corresponding to the measurement condition can be obtained. The background obtained from the measurement data is removed, and only the signal is extracted.
[0012]
In the embodiment of the X-ray diffraction measurement method of the present invention, the level adjustment of the intensity curve is performed by obtaining an average of the ratio of the intensity curve of the standard sample and the background intensity of the measurement sample within the measurement data range. By adjusting the intensity curve of the standard sample using the average of
[0013]
In the embodiment of the X-ray diffraction measurement method of the present invention, the level adjustment of the intensity curve is a ratio between the minimum value of the measurement data by the measurement sample and the intensity of the intensity standard curve of the standard sample at the same angle within the measurement data range. And adjusting the intensity curve of the standard sample using this ratio as a normalization constant. According to this, the process which calculates | requires a background part from the measurement data of a measurement sample can be abbreviate | omitted.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Since the X-ray diffractometer to which the present invention is applied is a well-known device, details of the X-ray diffractometer are omitted here.
FIG. 1 is a flowchart for explaining background removal of the X-ray diffraction apparatus of the present invention. Using an X-ray diffractometer that performs background removal processing, a standard sample is measured to obtain measurement data, a background curve is formed from the measurement data, and a background standard intensity stdI (a) is obtained. This background standard intensity stdI (a) represents the shape data of the curve corresponding to the background specific to the X-ray diffractometer.
[0015]
2 and 3 are a flowchart and a graph for explaining the background standard intensity stdI (a).
In order to obtain the background standard intensity stdI (a) using the standard sample, the measurement data of the standard sample is obtained (step S11), and the background point forming the background is selected from the measurement data (step S12). The selected points are connected to form a background curve, and this intensity curve can be set as the background standard intensity stdI (a) (step S13).
[0016]
FIG. 3A shows the measurement data obtained from the standard sample obtained in step S11. As a standard sample, a substance that does not emit fluorescent X-rays, can clearly distinguish the background component and the signal component, and has a known peak position is used. The operator observes the measurement data from the standard sample and selects the background. FIG. 3 (b) shows background points selected from the background, and FIG. 3 (c) shows a background curve formed by connecting the selected background points. For example, Si can be used as the standard sample.
In the background data, the background standard intensity stdI (a) obtained in step S1 depends on the X-ray diffractometer and is shape data of an intensity curve that does not depend on the measurement sample.
[0017]
On the other hand, since the intensity of the background data depends on the measurement conditions, the background intensity is obtained by the following steps S2, 3, and 4, and the intensity of the background standard intensity stdI (a) is adjusted according to the obtained intensity. To do.
[0018]
The sample to be measured is measured with an X-ray diffractometer (step S2), and the output level for the background of the measurement data is obtained. The output level for the background of the measurement data can be obtained by calculating the background intensity obsI (a) by a calculation process such as the Sonnebelt method that is conventionally performed on the measurement data. If there is a measurement point (for example, a minimum point) that can be identified as background in the measurement data, the output value at that point can be set as the background level (step S3).
[0019]
Next, the background intensity I (a) of the measurement data is obtained using the background standard intensity stdI (a) obtained in step S1 and the background level obtained in step S3. The background intensity I (a) of the measurement data represents the background in the measurement data, and the background removal can be performed by subtracting the background intensity I (a) from the measurement data (step S4). ).
[0020]
Hereinafter, a processing example for obtaining the background intensity I (a) of the measurement data in step S4 will be described using the flowchart of FIG. 4 and FIG.
Using the background intensity obsI (a) obtained in step S3 or the intensity of a specific point in the measurement data, the ratio of the intensity of the background of the measurement data and the background of the standard sample is obtained.
[0021]
Hereinafter, an example in which the background intensity obsI (a) is used will be shown.
FIG. 5A shows an example of measurement data to be measured. By performing an arithmetic process such as the Sonnebelt method on the measurement data, the background intensity of the measurement data shown in FIG. Get obsI (a).
FIG. 5C shows the background intensity obsI (a) of the measurement data and the background standard intensity stdI (a), and the ratio obsI (a) / stdI (a) of both is obtained in the range of the measurement data. Then, the intensity curve shown in FIG. 5D is obtained (step S41).
[0022]
The average of the background intensity ratios obsI (a) / stdI (a) obtained in step S41 is obtained (FIG. 5 (e)), and this value is used as the normalization constant α. The normalization constant α represents the ratio of the output level of the data background obtained from the measurement sample and the data background obtained from the standard sample.
[0023]
Therefore, when the background intensity I (a) (= stdI (a) × α) is obtained by multiplying the background standard intensity stdI (a) by the normalization constant α, the background intensity I (a) is output level. It becomes the background data of the corrected measurement data. FIG. 5F shows the background intensity I (a) obtained by performing the output level correction (step S43).
[0024]
When using the intensity of a specific point in the measurement data, the intensity of the selected specific point and the value of the background standard intensity stdI (a) at the same angle a are used to obtain the background intensity in the same manner as described above. The output level can be corrected.
It is also possible to divide the range of measurement data and perform output level correction by processing in the same manner for each division.
Accordingly, the intensity curve of the background data can be obtained in step S1, the intensity level of the background data can be obtained in steps S2, 3, and 4, and the level of the intensity curve can be adjusted according to the intensity level.
[0025]
The background intensity I (a) of the measurement data obtained in step S4 represents the background included in the measurement data. Therefore, by subtracting the background intensity I (a) from the measurement data, only the signal component in the measurement data is extracted. FIG. 6 shows signal processing for extracting the signal by subtracting the background from the measurement data. FIG. 6A shows measurement data, FIG. 6B shows background intensity I (a), and FIG. 6C shows measurement data and background intensity I (a). Here, when the background intensity I (a) is subtracted from the measurement data, a signal component in the measurement data is obtained as shown in FIG. 6D (step S5).
[0026]
FIG. 7 is a diagram for explaining conventional background removal. FIG. 7B shows a signal component obtained from the measurement data shown in FIG. 7A and the background intensity obsI (a) of the measurement data. Become. Compared with the signal obtained by the X-ray diffractometer of the present invention shown in FIG. 6C, the signal shown in FIG. Will be output low.
[0027]
【The invention's effect】
As described above, according to the X-ray diffraction measurement method of the present invention, appropriate background removal can be performed using appropriate background data that does not depend on the measurement target.
[Brief description of the drawings]
FIG. 1 is a flowchart for explaining background removal of an X-ray diffraction measurement method of the present invention.
FIG. 2 is a flowchart for explaining a background standard intensity stdI (a).
FIG. 3 is an output diagram for explaining a background standard intensity stdI (a).
FIG. 4 is a flowchart for explaining a processing example for obtaining a background intensity I (a) of measurement data.
FIG. 5 is an output diagram for explaining a processing example for obtaining a background intensity I (a) of measurement data.
FIG. 6 is an output diagram for explaining signal processing for extracting a signal component by subtracting a background component from measurement data;
FIG. 7 is an output diagram for explaining conventional signal processing for extracting a signal component by subtracting a background component from measurement data.
[Explanation of symbols]
stdI (a): Background standard intensity, obsI (a): Background intensity of measurement data, I (a): Background intensity of measurement data after correction.

Claims (1)

In an X-ray diffraction measurement method for correcting data by removing background data from measurement data of X-ray diffraction measurement,
The background has an intensity curve and an intensity level with respect to the angle,
For the intensity curve, a background curve is formed by selecting a background intensity not resulting from the measurement target of the standard sample from the measurement data of the standard sample,
For the intensity level, the background intensity based on the measurement conditions is obtained from the measurement data of the measurement target sample,
An X-ray diffraction measurement method comprising adjusting an intensity curve level according to an intensity level.

Images