JPH06151089A - X-ray analyzing device and x-ray analyzing method - Google Patents

Abstract

PURPOSE:To allow the measurement at high X-ray intensity, in an EXAFS measuring device, by using an X-ray generating device with low voltage and large current. CONSTITUTION:In an EXAFS measuring device, the continuous X-ray emitted from an X-ray focus F is spectrally divided and monochromated by a monochromator 14, and this is emitted to a sample 25 to measure the X-ray transmissivity of the sample 26. The used X-ray generating device allows low voltage and large current, and by using a large-size rotating paired negative electrode with a diameter of 25cm as an X-ray tube, a tube current of 900mA can be provided when the tube voltage is 20kV. Thus, the measurement can be performed at a high X-ray intensity even with a comparatively low voltage, and the measuring time is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention analyzes a sample by separating continuous X-rays to extract monochromatic X-rays of an arbitrary wavelength, irradiating the sample by changing the wavelength of the monochromatic X-rays. The present invention relates to an X-ray analysis apparatus (mainly EXAFS measurement apparatus) and an X-ray analysis method, and more particularly, to an X-ray analysis apparatus and an X-ray analysis method characterized by the X-ray generation apparatus.

[0002]

2. Description of the Related Art An EXAFS (X-ray wide area absorption fine structure) measuring apparatus is an apparatus for measuring a fine X-ray absorption spectrum near the absorption edge of a sample. In this device, continuous X-rays are spectrally separated by a crystal monochromator to extract monochromatic X-rays of an arbitrary wavelength, and this wavelength can be changed to measure the X-ray absorption coefficient of a sample. As a crystal monochromator for spectrally analyzing X-rays, a curved crystal monochromator is often used to gain strength.

As an X-ray source for EXAFS measurement,
It is ideal to use synchrotron radiation that can obtain high-intensity continuous X-rays, but facilities that have facilities for synchrotron radiation are limited. As EXAFS measurement has become popular, there is an increasing need to perform EXAFS measurement using an X-ray generator installed in a laboratory without using synchrotron radiation. EXA at such a laboratory level
In the FS measuring apparatus, it is preferable that the X-ray generator can obtain the X-ray intensity as large as possible. In order to increase the intensity of the generated X-rays, the current of the electron beam that collides with the target of the X-ray tube, that is, the tube current may be increased. In order to increase the tube current, generally, the tube voltage is increased. As a result, since the electric power supplied to the X-ray tube becomes large, a rotating anticathode capable of supplying a large electric power is often used as the X-ray tube.

The following are conventional X-ray generators used in the EXAFS measuring device. For example, a small rotating anticathode with a diameter of about 10 cm and a maximum power of 18 kW
There is an X-ray generator that combines a power source with a maximum voltage of 60 kV and a maximum current of 300 mA to extract an X-ray beam at a line focus. As another example, a large rotating anticathode with a diameter of about 25 cm and a maximum power of 60 kW (maximum voltage 60 kV, maximum current 1000 mA)
There is also an X-ray generator which is combined with a power source for extracting a point-focused X-ray beam. Further, there is a large rotating anticathode X-ray generator which is specially modified to realize a line focus (Japanese Patent Application No. 4-19).
5866).

[0005]

When the tube voltage is increased in order to increase the tube current, there are the following problems. When the tube voltage is increased, the energy distribution of X-rays generated at the target spreads toward the short wavelength side. That is, high-energy X-rays are mixed. In the EXAFS measuring device, an X-ray beam generated by an X-ray tube is separated by a crystal monochromator, but if high-energy X-rays are mixed in continuous X-rays, the monochromator monochromates the X-rays. Occasionally, X-rays (hereinafter referred to as
It is called harmonic X-ray. ) Will also come out of the monochromator at the same time. For example, the absorption edge energy of copper is 8.98 keV, but if the monochromator is set so as to extract 8.98 keV X-rays, second harmonic 17.98 keV X-rays will also come out.

In such a case, the tube voltage is 17.5 kV.
In this case, since the above-mentioned second harmonic is not included in the continuous X-ray, it is possible to prevent the harmonic X-ray from coming out.
That is, it is preferable that the tube voltage of the X-ray generator is continuously variable in the low voltage region and is set to a tube voltage at which harmonic X-rays are not generated according to the measurement target. In a practical EXAFS measuring device, it is preferable to use the tube voltage in the range of about 10 to 30 kV. However, the conventional small rotating anticathode X-ray tube has a maximum voltage of 200 to 300 mA in this tube voltage range.
Only the tube current of a certain degree is obtained. Therefore, there is a problem that sufficient X-ray intensity cannot be obtained. When the X-ray intensity is low, the measurement time of EXAFS measurement becomes long, and it becomes difficult to apply it to an actual measurement target. Therefore, 10-30k
Achieving a large tube current at a tube voltage as low as V becomes an important issue.

An object of the present invention is to analyze a sample by spectrally analyzing continuous X-rays, extracting monochromatic X-rays of an arbitrary wavelength, irradiating the sample by changing the wavelength of the monochromatic X-rays.
In the line analysis device (mainly EXAFS measurement device),
By using a low voltage, high current X-ray generator,
This is to enable measurement with a large X-ray intensity.

[0008]

According to a first aspect of the present invention, continuous X-rays are dispersed to extract monochromatic X-rays of an arbitrary wavelength, and the wavelength of the monochromatic X-rays is changed to irradiate the sample. In an X-ray analyzer for analysis, the X-ray beam extracted from the X-ray generator has an apparent focal width of 0.15.
It is a line focus beam of mm or less, the maximum tube current of the X-ray generator is 300 mA or more, and the ratio between the maximum tube current Imax of the X-ray generator and the maximum tube voltage Emax satisfies the following expression. It was done like this.

[0009]

## EQU4 ## Imax (mA) / Emax (kV) ≧ 20

In the present invention, the maximum tube voltage means the maximum allowable tube voltage as the capacity of the X-ray generator. Further, the maximum tube current means the maximum allowable value of the tube current as the capability of the X-ray generator. In this case, the maximum tube current is not always obtained at the maximum tube voltage. This is because the maximum heat load of the X-ray tube cannot be exceeded and power cannot be applied to the X-ray tube. For example, the maximum tube voltage is 30 kV, the maximum tube current is 900 mA, and the maximum heat load is 18
An example of a kW X-ray generator shows a tube voltage of 20 kV.
A maximum tube current of 900 mA can be obtained. The input power at this time is 18 kW. When the tube voltage is raised to the maximum value of 30 kV, the tube current is limited to 600 mA. The input power at this time is also 18 kW. In the X-ray generator of this example, the characteristic of the apparatus itself is Imax / Emax = 30.

A second invention is characterized in that, in the first invention, the X-ray analyzer is an EXAFS measuring device. A third invention is the second invention, wherein the maximum tube voltage is 10 to 30 kV.

A fourth invention is an X-ray analysis for analyzing a sample by separating continuous X-rays to extract monochromatic X-rays having an arbitrary wavelength, irradiating the sample by changing the wavelength of the monochromatic X-rays. In the method, the X-ray beam extracted from the X-ray generator is a line-focus beam having an apparent focal width of 0.15 mm or less, the tube current of the X-ray generator is 300 mA or more, and the X-ray generation is performed. The ratio of the tube current I to the tube voltage E of the device satisfies the following equation.

[0013]

[Equation 5] I (mA) / E (kV) ≧ 20

According to the present invention, the ratio between the tube voltage and the tube current when the X-ray generator is actually used is specified. For example, in the case of the X-ray generator exemplified in the above-mentioned first invention, Imax / Emax = 30, but the ratio of the tube voltage and the tube current during actual use changes,
I / E when the tube voltage is 20 kV and the tube current is 900 mA
= 45, the tube voltage is 30 kV and the tube current is 600 mA.
In this case, I / E = 20.

A fifth aspect of the present invention is the same as the fourth aspect of the present invention, in which the ratio of the tube current I to the tube voltage E satisfies the following equation when the tube voltage is in the range of 10 to 20 kV.

[Equation 6] I (mA) / E (kV) ≧ 40

[0016]

[Function] The ratio between the maximum tube current and the maximum tube voltage is Imax / E
By setting max ≧ 20, an X-ray generator with low voltage and large current can be obtained. The present invention has developed an X-ray generator having such a ratio so as to be particularly suitable for an X-ray analyzer that separates continuous X-rays and uses monochromatic X-rays of an arbitrary wavelength. Conventionally, an X-ray generator having a ratio of maximum tube current to maximum tube voltage as in the present invention has not been commercially available, and according to the present invention, an X-ray generator having a low voltage and a large current can be used for the first time. As a result, a high-intensity X-ray beam containing no harmonic X-rays can be obtained from the monochromator.

In the present invention, the X-ray beam extracted from the X-ray generator is limited to the line focus beam having an apparent focal width of 0.15 mm or less. In order to increase the ratio of the tube current to the tube voltage, a method of increasing the focal area on the anticathode of the X-ray tube can be considered, and this is not so difficult. For example, if the focal dimension of 1 mm × 10 mm is expanded to 2 mm × 10 mm, it becomes easy to take a large tube current. However, when the focal width is increased, the apparent focal width of the extracted X-ray beam is also increased, which deteriorates the wavelength resolution of the monochromator. When the X-ray extraction angle is 6 °, the apparent focal width is about 1/10 of the focal width on the anticathode. Therefore, when the focal width is 1 mm, the apparent focal width is 0.1
mm, and when the focal width is 2 mm, the apparent focal width is 0.2 mm. In the present invention, the apparent focal width is set to 0.
An X-ray generator with a low voltage and a large current is realized while keeping the distance to 15 mm or less, that is, keeping the wavelength resolution of the X-ray analyzer good.

The maximum tube current is preferably at least 300 mA or more. The value of 300 mA is for an X-ray generator with a maximum tube voltage of around 10 kV. With an X-ray generator with a maximum tube voltage of 20 to 30 kV,
It is preferable to obtain a maximum tube current of 700 mA or more.
As a result, a large X-ray intensity is obtained in the EXAFS measuring device, and the measurement time is shortened as compared with the conventional laboratory-level EXAFS measuring device. In order to avoid harmonic X-rays from the monochromator, the tube voltage should be 30k.
It is preferably V or less. Therefore, it is not necessary for the maximum tube voltage of the X-ray generator to exceed 30 kV. Further, considering the practical X-ray wavelength range used in the EXAFS measurement device, the maximum tube voltage of the X-ray generation device needs to be 10 kV or more.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an embodiment in which the present invention is applied to an EXAFS measuring device. This EXAFS measuring device includes an X-ray focus F, a curved crystal monochromator 14, and
The light-receiving slit RS is connected to the rotating arms 16, 18, and 20, respectively, and the X-ray focus F, the center of the curved crystal monochromator 14, and the opening center of the light-receiving slit RS are
They are always placed on the same circumference of the Roland circle 22. Then, using a biaxial translation stage, the distance x1 from the X-ray focus F to the center of the monochromator 14 and the distance x2 from the center of the monochromator 14 to the opening center of the light-receiving slit RS are independently set. The distance between them is controlled to be the same (x1 = x2 = L).

The continuous X-ray emitted from the X-ray focal point F passes through the divergence slit DS, is reflected by the monochromator 14 to be monochromatic, and reaches the light receiving slit RS. Light receiving slit RS
X-rays that have passed through pass through the transmission type proportional counter 24,
It passes through the sample 26 and reaches the scintillation detector 28. The X-ray intensity before passing through the sample 26 is the proportional counter 24
The X-ray intensity after being transmitted through the sample 26 is detected by a scintillation detector 28. By comparing the X-ray intensities of the sample 26 before and after transmission, the X-ray absorption coefficient of the sample 26 can be obtained. The wavelength of the X-ray reflected by the monochromator 14 can be changed by changing the value of the distance L and changing the X-ray incident angle on the monochromator 14. If the X-ray absorption coefficient of the sample 26 is measured by changing the wavelength of the X-ray in this way, the sample 2
The absorption spectrum of 6 can be obtained.

FIG. 2 is a graph showing the relationship between the tube voltage and the tube current of the X-ray generator. The curve ABC is X in the first embodiment.
It is a tube voltage / tube current curve of a line generator. This curve is
The maximum possible tube current for each tube voltage is shown. This X-ray generator has a maximum tube voltage of 30k.
V, the maximum tube current is 900 mA, and the maximum heat load is 18 kW. Maximum tube current (mA) for maximum tube voltage (kV)
Is 30. Curve 52 is an isothermal load curve with an electric power of 18 kW. This X-ray generator has a tube voltage of 10 to 3
Used in the 0 kV range. When the tube voltage is 10 kV, a maximum tube current of 400 mA is obtained (point A). At this time, the ratio of the tube current (mA) to the tube voltage (kV) (hereinafter referred to as the current-voltage ratio) is 40. When the tube voltage is increased from 10 kV to 20 kV, the possible tube current increases to 900 mA (point B). The electric power at this time becomes 18 kW, and reaches the isothermal load curve 52. The current-voltage ratio at this time is 45. In order to further increase the tube voltage, it is necessary to decrease the tube current along the isothermal load curve 52 so as not to exceed the maximum heat load of 18 kW of the X-ray tube, which is 600 mA at 30 kV (C point). The current-voltage ratio at this time is 20. When using this X-ray generator, the maximum value of the tube current at each tube voltage is defined by the curve ABC.
It can be operated with a tube current smaller than BC. However, the lower limit of the tube current is the straight line 56 showing the tube current of 300 mA.
And a straight line 50 indicating the current-voltage ratio 20.
In practice, it is common to use on the maximum possible current, curve ABC, in order to maximize the X-ray intensity. This X-ray generator has a tube voltage of 10 to 20k.
As far as the range of V is concerned, the current-voltage ratio is 40 or more, and the characteristics of low voltage and large current are remarkable. Further, this tube voltage range is also a very often used range in the EXAFS measurement device.

The curve DEFG is a tube voltage / tube current curve of the X-ray generator of the second embodiment. This X-ray generator has a maximum tube voltage of 30 kV, a maximum tube current of 1350 mA, and a maximum heat load of 30 kW. The ratio of the maximum tube current (mA) to the maximum tube voltage (kV) is 45. Curve 54 is an isothermal load curve with a power of 30 kW. This X-ray generator is also used within a tube voltage range of 10 to 30 kV. When the tube voltage is 10 kV, a maximum tube current of 500 mA is obtained (point D). The current-voltage ratio at this time is 50. When the tube voltage is increased from 10 kV to 20 kV, the possible tube current rises to 1200 mA (E
point). The current-voltage ratio at this time is 60. When the tube voltage is 22.2 kV, the tube current becomes 1350 mA, the power becomes 30 kW (point F), and the isothermal load curve 54 is reached. In order to further increase the tube voltage, it is necessary to decrease the tube current along the isothermal load curve 54 so as not to exceed the maximum heat load of 30 kW of the X-ray tube, which is 1000 mA at 30 kV (G point). The current-voltage ratio at this time is 33.3. This X-ray generator has a tube voltage of 1
Speaking only in the range of 0 to 20 kV, the current-voltage ratio is 50
As described above, the characteristics of low voltage and large current are remarkable.

In the shaded area 62, a straight line 58 showing a tube voltage of 10 kV, a straight line 60 showing a tube voltage of 30 kV, a straight line 50 showing a current-voltage ratio of 20, and a straight line 5 showing a tube current of 300 mA.
A region surrounded by 6 is a region that satisfies the tube voltage and tube current conditions of the present invention. X-ray generators other than the above two embodiments may be used as long as they are included in this region. With the X-ray generator included in the region 62,
A large tube current can be obtained even at a relatively low tube voltage.

The X-ray generator developed by the inventor has a maximum tube current of up to about 1300 mA, but an X-ray generator having a maximum tube current exceeding this is of course acceptable, but rather large. Good.

FIG. 3 is a perspective view of the vicinity of the target of the X-ray tube of the X-ray generator shown by the curve ABC in FIG. This X
The wire tube comprises a rotating anticathode with a diameter of 250 mm.
The cylindrical anticathode 29 rotates about a horizontal axis of rotation. An electron beam 32 is emitted from the filament 30 which is an electron beam generation source toward the anticathode 29, and a focus 34 is formed on the outer peripheral surface 33 of the anticathode 29. The focal point 34 has an elongated shape of 1 mm × 10 mm, and its longitudinal direction coincides with the circumferential direction of the outer peripheral surface 33 of the anticathode 29. The filament 30 is arranged so as to extend in the vertical direction as a whole so as to face the anticathode 29, whereby
The vertically long focus 34 is formed as described above. Anticathode 29
An X-ray extraction window 36, 37 is provided in a vacuum container for accommodating the filament 30 and the filament 30 therein, and an X-ray beam 38 having a line focus from the extraction window 36, 37.
Can be taken out horizontally.

FIG. 4 is a horizontal sectional view in the vicinity of the electron gun of the X-ray tube of the X-ray generator shown by the curve ABC in FIG. There is a filament 30 facing the anticathode 29, and an inner Wehnelt electrode 40 and an outer Wehnelt electrode 42 are arranged in the vicinity of the filament 30. Filament 3
An inner opening 41 is formed in the inner Wehnelt electrode 40, and an outer opening 43 is formed in the outer Wehnelt electrode 42 in order to allow the electron beam from 0 to pass therethrough. The electron beam emitted from the filament 30 is focused by the Wehnelt electrode and irradiated on the surface of the anticathode 29, and the X-ray beam 38 is generated from there. The X-ray beam 38 is extracted at an extraction angle α = 6 °. Extracted X-ray beam 38
The apparent focal width of is 0.1 mm in this embodiment.
This apparent focal width is practically 0.05 to 0.15.
The range of mm is preferred. If the apparent focal width becomes larger than this, the deterioration of the wavelength resolution in the monochromator cannot be ignored.

The electron gun of FIG. 4 was developed for a low voltage, large current X-ray generator. The specifications are shown in Table 1 below.

[0028]

[Table 1] Dimensions of filament 30 Coil length 17.7
mm Coil diameter 5 mm Dimension of inner opening 41 Dimension of F2 in FIG. 4 8 mm Dimension in the direction perpendicular to the paper surface 22 mm Dimension of outer opening 43 Dimension of F1 in FIG. 4 10 mm Dimension in the direction perpendicular to the paper surface Distance S 6 in FIG. .3 mm potential of the anticathode 29, ground potential, potential of the filament -20 kV (tube voltage is 20 kV
V) Potential of the inner Wehnelt electrode 40 is the same potential as the filament 30. Potential of the outer Wehnelt electrode 42 is 0 to -2 kV with respect to the filament 30. Focus size on the anticathode 29 is 1 mm x 10 mm.

The following points were taken into consideration in developing the electron gun. To increase the tube current, the filament 30
The distance S between the cathode and the anticathode 29 may be reduced. Therefore, the filament 30 is used as an anti-cathode 29 compared with the conventional electron gun.
Approached to. In addition, the size of the focal point is expanded by simply bringing them closer to each other. Therefore, the size of the Wehnelt electrode is changed so that the focal size becomes a specified size of 1 mm × 10 mm. Table 2 below shows a size comparison between the conventional electron gun and the electron gun of the embodiment.

[0030]

[Table 2]

FIG. 5 is a graph of an absorption spectrum measured to evaluate the EXAFS measuring apparatus using the X-ray generator shown by the curve ABC in FIG. This graph is a comparison of the X-ray absorption spectrum in the vicinity of the absorption edge of a copper foil used as a sample between the measurement by the EXAFS measurement apparatus of this example and the EXAFS measurement using synchrotron radiation. (A) is an example measured by the EXAFS measuring apparatus of this embodiment, and Ge (4
40), the tube voltage of the X-ray generator is 17.5 kV,
The tube current is 700 mA. In this case, the current-voltage ratio is 40. (B) is an example of measurement by sinktrotron radiation. Synchrotron radiation produces very intense continuous X-rays and is an ideal X-ray source for EXAFS measurements. Therefore, the measurement by synchrotron radiation gives a high-resolution absorption spectrum, which can be used as a reference for evaluation. As can be seen from FIG. 5, the absorption spectrum (a) obtained in this example is almost the same as the absorption spectrum (b) obtained by synchrotron radiation, and there is no problem in terms of resolution. The incident X-ray intensity on the sample when Ge (220) was used as the monochromator and the tube current was 700 mA was several million cps (counts / second) at the X-ray energy near the absorption edge of copper. Since such an extremely large incident X-ray intensity can be obtained, EXAFS measurement can be performed in about 30 minutes to several hours for most samples.

FIG. 6A shows X indicated by the curve ABC in FIG.
It is a graph which performed EXAFS measurement of the actual sample using the line generator. The sample is Cu30V70 powder,
The tube voltage is 17.5 kV and the tube current is 700 mA. The measurement time is about one and a half hours. FIG. 6B shows the result of Fourier transform of the vibration component of the absorption spectrum of FIG. This data is in very good agreement with the data obtained with synchrotron radiation for the same sample. From this, it was found that the EXAFS measurement apparatus of the present example can obtain data with sufficient quality within a realistic time.

FIG. 7 is a graph showing an example in which the characteristic X-ray of tungsten is suppressed by controlling the tube voltage using the X-ray generator shown by the curve ABC in FIG. When tungsten is used as the material of the filament of the X-ray tube, when the filament evaporates and adheres to the target, the characteristic X-ray of tungsten is mixed in the incident X-ray. The characteristic X-ray of this tungsten is very strong,
If it enters the FS measurement range, it will adversely affect the measurement results. FIG. 7 shows the measurement of the transmitted X-ray intensity in the vicinity of the K absorption edge of nickel. It can be seen that the Lα ray of tungsten appears strongly when the tube voltage is 15.5 kV. On the other hand, when the tube voltage is 10 kV, the characteristic X-ray of tungsten does not appear. The reason is that energy of 10.2 keV or more is required to excite 2p electrons of tungsten. As described above, depending on the sample, it is necessary to perform the measurement at a low tube voltage of 10 kV. Even in this case, however, the tube current is 400 in this embodiment.
This is advantageous because it can secure mA.

In the first embodiment described above, since the large rotating anticathode having a diameter of 25 cm is used with the special focus arrangement as shown in FIG. 3, the maximum allowable heat load is limited to 18 kW. However, even in this case, 900 m at 20 kV
It was possible to obtain a large tube current of A (the current capacity of the high-voltage power supply is 1000 mA). The maximum tube current can also be increased by increasing the maximum allowable heat load by using a large rotating anticathode with a larger diameter. In that case, it is necessary to further increase the current capacity of the high-voltage power supply of the X-ray generator.

The present invention is not limited to the one using a large rotating anticathode, but a small rotating anticathode having a diameter of about 10 cm may be used. This small rotating anticathode is widely used for various purposes and has high versatility. Even when the small rotating anticathode is used, a low voltage, large current X-ray tube can be realized by using the electron gun shown in FIG.
In the case of the small rotating anticathode, as shown in FIG.
The X-ray beam 68 having a line focus is extracted by arranging a general focus arrangement in which the longitudinal direction of the X axis and the axial direction of the rotating anticathode 64 are parallel to each other. The maximum allowable heat load in this case is 12 to 18 kW when the focal point size on the anticathode is 0.5 mm × 10 mm. Therefore, the maximum permissible heat load equivalent to that of the large rotating anticathode of the first embodiment is obtained, and the present invention can be applied even if the diameter of the rotating anticathode is small.

Conventionally, a small rotating anticathode X-ray generator could obtain only a tube current of 200 to 300 mA at most, but this time, the second rotating small cathode with a diameter of 10 cm was used.
In the example, the characteristics shown by the curve DEFG in FIG. 2 were obtained. As a result, a maximum tube current of about 1300 mA was obtained. This has been made possible by implementing the following improvements that have not been attempted in the past. That is, the low-voltage high-current specification shown in FIG. 4 is used as the electron gun including the filament, and the focal dimension is large on the anticathode to 1 mm × 10 mm. In this way, the maximum allowable heat load could be improved to 30 kW by increasing the focal dimension and improving the water cooling system of the anticathode.

Conventionally, most X-ray generators have been manufactured for the purpose of X-ray diffraction experiments, and most of them set the rated tube voltage at 60 kV. Correspondingly, it has been common to define the maximum tube current of the X-ray tube by the current value at this rated tube voltage. For example, the maximum allowable heat load is 1
With an 8 kW X-ray tube, the maximum tube current is 300 mA. The structure of the electron gun including the filament and the structure of the power supply have been designed according to the maximum tube current. However, if it is assumed that the X-ray generator is used at a relatively low tube voltage, as in the EXAFS experiment, even if the X-ray tube has the same maximum allowable heat load, a larger tube current is generated. In principle, it is possible to obtain it. As a result, the X-ray generator shown by the curve DEFG of FIG. 2 was obtained in the small rotating anticathode.

The present invention is not limited to the EXAFS measuring device, but can be applied to other X-ray analyzing devices in which continuous X-rays are dispersed to extract monochromatic X-rays of an arbitrary wavelength and irradiate the sample.

[0039]

According to the present invention, the ratio between the maximum tube current Imax and the maximum tube voltage Emax of the X-ray generator is Imax / Emax ≧.
By setting the value to 20, an X-ray generator with a low voltage and a large current can be obtained. As a result, continuous X with a monochromator
In the X-ray analyzer of the type that disperses X-rays, the harmonic X
A high-intensity X-ray beam containing no rays will be obtained from the monochromator.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a tube voltage and a tube current of an X-ray generator.

FIG. 3 is a perspective view of the vicinity of the target of the X-ray tube.

FIG. 4 is a horizontal sectional view of the X-ray tube in the vicinity of an electron gun.

FIG. 5 is a graph of an absorption spectrum comparing an example of measurement by the apparatus of the example and an example of measurement by synchrotron radiation.

FIG. 6 shows an EXAFS of a real sample using the apparatus of the embodiment.
It is a graph of the measured absorption spectrum.

FIG. 7 is a graph showing the transmitted X-ray intensity measured near the K absorption edge of nickel.

FIG. 8 is a perspective view of the vicinity of a target of an X-ray tube of an X-ray generator of another embodiment.

[Explanation of symbols]

 14 ... Monochromator 24 ... Transmission type proportional counter 26 ... Sample 28 ... Scintillation detector F ... X-ray focus

Claims (5)

[Claims] 1. A monochromatic X having an arbitrary wavelength obtained by spectrally analyzing continuous X-rays.
In an X-ray analyzer for analyzing a sample by extracting the X-ray and changing the wavelength of the monochromatic X-ray and irradiating the sample, the X-ray beam extracted from the X-ray generator has an apparent focal width of 0. It is a line focus beam of 15 mm or less, the maximum tube current of the X-ray generator is 300 mA or more, and the maximum tube current Imax and the maximum tube voltage Ema of the X-ray generator.
An X-ray analyzer characterized in that the ratio with x satisfies the following formula. ## EQU1 ## Imax (mA) / Emax (kV) ≧ 20 2. The X-ray analysis apparatus according to claim 1, wherein the X-ray analysis apparatus is an EXAFS measurement apparatus. 3. The X-ray analysis apparatus according to claim 2, wherein the maximum tube voltage is 10 to 30 kV. 4. A continuous color X-ray is dispersed to obtain a monochromatic X having an arbitrary wavelength.
In an X-ray analysis method in which a sample is analyzed by extracting the X-ray and irradiating the sample by changing the wavelength of the monochromatic X-ray, the X-ray beam extracted from the X-ray generator has an apparent focal width of 0. A line focus beam of 15 mm or less, a tube current of the X-ray generator of 300 mA or more, and X
An X-ray analysis method, characterized in that the ratio of the tube current I and the tube voltage E of the ray generator satisfies the following equation. ## EQU2 ## I (mA) / E (kV) ≧ 20 5. The tube voltage of the X-ray generator is 10 to 20 kV.
The X-ray analysis method according to claim 4, wherein the ratio of the tube current I to the tube voltage E satisfies the following equation in the range of. [Equation 3] I (mA) / E (kV) ≧ 40