JPH09101270A - Sample position confirming method for x-ray diffractometer, sample container, and x-ray microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm the positional relation between a sample housed in a sample container and the route of X rays even when the sample is not visually confirmable by confirming the position of the sample using secondary X rays generated by foil interposed between a collimator and the sample. SOLUTION: X rays 11 radiated from an X-ray source 10 are made incident to foil 14 after being converged into a narrow beam through a pin-hole collimator 12. Secondary X rays (fluorescent X rays) 20 generated from the area of the foil 14 irradiated with the X rays reach a two-dimensional X-ray detector 22 after passing through a sample 18 in a sample container 16 and its peripheral space. Therefore, the outline of the sample 18 can be recognized as an enlarged picture 24. When this X-ray microscope is utilized as a sample position confirming means for X-ray diffractometer, beryllium which makes the sample contained in the container invisible can be used as the material of the sample container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray microscope using secondary X-rays, and a method for confirming the sample position of an X-ray diffraction apparatus using the principle of this X-ray microscope. The present invention relates to a sample container that can be used for this sample position confirmation method.

[0002]

2. Description of the Related Art When X-ray diffraction measurement of a protein crystal is performed, the protein crystal is put inside a glass capillary and sealed together with a mother liquor in order to prevent the protein crystal from being altered. In order to adjust the positional relationship between the incident X-ray and the sample for such a sample, the sample inside the glass capillary is observed using a sample observation microscope, and the sample (or X The position of the sample holder that supports the glass capillary is adjusted so that the sample portion to which the line is to be irradiated) comes. The center of the visual field of the microscope is adjusted in advance so that it coincides with the X-ray irradiation position.

[0003]

When the glass capillary as described above is used, the amount of scattered X-rays from the glass is relatively large, so that the background level of the X-ray diffraction measurement is raised, and the diffraction X to be detected is detected. There is a drawback that the S / N ratio of the line deteriorates. Glass is not necessarily suitable as a material for enclosing a sample in an X-ray diffractometer because it has a large X-ray scattering ability, a large X-ray absorption, and cannot be made very thin. It has been used as a sample container so far because of its advantage that the sample inside can be viewed because it is transparent. But,
In order to carry out the X-ray diffraction measurement of a sample which is easily deteriorated with high accuracy, scattered X-rays from glass, which is the material of the sample container, is an obstacle.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to make it possible to confirm the position of a sample even when a sample container whose inside cannot be visually observed in an X-ray diffraction apparatus is used. It is to provide a position confirmation method. Another object of the present invention is to provide an X-ray microscope that can be used for the above-mentioned sample position confirmation. Still another object of the present invention is to provide a sample container which is less affected by scattered X-rays in an X-ray diffractometer.

[0005]

According to the sample position confirmation method of the present invention, an X-ray that has passed through a collimator is applied to the sample, and the diffracted X-ray from this sample is measured by a two-dimensional X-ray detector. In a line diffractometer, a foil is inserted in the X-ray path between the collimator and the sample, the foil is irradiated with X-rays, and the sample is irradiated with secondary X-rays emerging from the back surface of the foil. Then, the secondary X-rays that have passed through the sample and its surrounding space are detected by the two-dimensional X-ray detector to confirm the positional relationship between the sample and the X-ray path. . As a result, the positional relationship between the sample and the X-ray path can be confirmed without visually observing the sample inside the sample container. Therefore, the sample container can be manufactured by selecting an optimum material with a small amount of scattered X-rays without being restricted by visible light transmission. Beryllium is the most suitable material for the sample container, and carbon can also be used.

Further, the X-ray microscope of the present invention irradiates the foil with X-rays that have passed through the collimator, and irradiates the sample arranged near the foil with secondary X-rays emerging from the back surface of the foil. Then, the secondary X transmitted through this sample and its surrounding space.
It is characterized in that a magnified image of the sample is obtained by detecting the line with a two-dimensional X-ray detector separated from the sample. Such an X-ray microscope can be incorporated in an X-ray diffractometer and can be used for work for confirming the position of a sample.

Further, the sample container according to the present invention is a container made of beryllium or carbon in which the sample is hermetically sealed. This sample container is suitable for use in X-ray diffraction measurement of protein crystals, for example. By using this sample container, X-ray diffraction measurement with less background can be carried out in a state where the protein crystals are maintained in the mother liquor atmosphere and the influence of scattered X-rays from the sample container is reduced.

[0008]

FIG. 1 is a perspective view showing an embodiment of the X-ray microscope of the present invention. The X-ray (primary X-ray) 11 emitted from the X-ray source 10 is focused into a thin beam by the pinhole collimator 12 and is incident on the foil 14. X-ray 1 on foil 14
When 1 hits, secondary X-rays (fluorescent X-rays) diverge from the X-ray irradiation area of the foil 14 in all directions. Of these secondary X-rays, the secondary X-rays 20 coming out from the back side of the foil 14 pass through the sample 18 in the sample container 16 and the surrounding space thereof,
It reaches the two-dimensional X-ray detector 22. Since the X-ray intensities of the secondary X-rays that have passed through the sample 18 and the secondary X-rays that have passed through the outside of the sample 18 are different, the outer shape of the sample 18 is enlarged in the two-dimensional X-ray detector 22. It can be recognized as 24. Furthermore, if the X-ray transmittance differs depending on the transmission place of the sample 18, the X-ray transmittance distribution in the sample can be recognized as an enlarged image.

FIG. 2 is a side view of the X-ray microscope shown in FIG. A foil 14 is arranged near the exit hole of the collimator 12, and a sample container 16 is arranged near the back side of the foil 14. Then, the two-dimensional X-ray detector 22 is arranged at a position apart from the sample container 16. When the distance from the foil 14 to the sample 18 is a and the distance from the sample 18 to the two-dimensional X-ray detector 22 is b, the magnification of this X-ray microscope is (a
+ B) / a. For example, a = 1 mm, b = 100-
When it is set to 200 mm, the magnification is 100 to 200 times.

The material of the foil 14 is a material that easily generates secondary X-rays, such as Fe (iron), Au (gold), and Ni.
(Nickel), Cu (copper), Al (aluminum), etc. can be used. When the material of the foil is changed, the wavelength of the secondary X-ray (which is the characteristic X-ray of the material of the foil) is changed. Therefore, if the wavelength is desired to be changed, the material of the foil may be changed. A suitable thickness of the foil 14 is 10 to 100 μm. The foil 14 is preferably amorphous. When the foil 14 is made crystalline, the diffracted X-rays from the crystals may become noise to the transmission image of the sample, but when the foil 14 is made amorphous, the influence of such diffracted X-rays disappears.

The inner diameter of the exit hole of the collimator 12 should be as small as possible. That is, the irradiation area of the X-ray beam that strikes the foil 14 should be as small as possible. When the irradiation area is small, the area where the secondary X-rays are generated is small, and the blur of the enlarged image on the two-dimensional X-ray detector is small. The inner diameter of the exit hole of the collimator 12 is preferably about 10 μm.

In the X-ray microscope, the sample 18 does not necessarily have to be stored inside the sample container 16, but the sample may be placed on the sample holder, or the sample holding plate through which X-rays easily pass is used. The sample may be attached.

The two-dimensional X-ray detector 22 is a known two-dimensional X-ray such as an imaging plate (also called a stimulable phosphor or a stimulable phosphor), a combination of a fluorescent plate and a CCD camera, and an X-ray film. A detector is available.

By the way, an X-ray microscope using primary X-rays (irradiating an electron beam on the back side of the target,
It is known that X-rays are extracted from the surface of a target to obtain a transmission image of a sample placed near the target. On the other hand, X using the secondary X-ray as in the present invention
The line microscope can bring the sample closer to the X-ray source (foil in the present invention) for obtaining a magnified image, as compared with the one using the primary X-ray, and thus the magnifying power can be increased. . In addition, since the wavelength of the secondary X-ray can be changed simply by changing the material of the foil, the wavelength can be changed easily. Further, as described later, there is an advantage that it can be incorporated in an X-ray diffractometer.

Next, an example in which the X-ray microscope of FIG. 1 is used as means for confirming the position of a sample will be described by taking the case of carrying out the X-ray diffraction measurement of a protein crystal as an example.

FIG. 3 is an enlarged side sectional view of the sample container 16a of the X-ray diffraction apparatus. The sample container 16a includes a cylindrical portion 30, a bottom 32, and a lid 34, and all of these parts are made of beryllium having a thickness of 10 μm. Since beryllium easily transmits X-rays and can be made thin, the scattered X-rays are smaller than those of glass capillaries, and the background during X-ray diffraction measurement is small. But,
Since visible light is not transmitted, there is a drawback that the inside of the sample container 16a cannot be visually observed. Therefore, the position of the protein crystal 18a inside the sample container 16a can be confirmed using the X-ray microscope shown in FIG.

The space between the cylindrical portion 30 and the bottom 32 and the space between the cylindrical portion 30 and the lid 34 are hermetically sealed with an adhesive. The protein crystal 18a is attached to the inner wall of the sample container 16a in a wet state with the mother liquor. The mother liquor 3 is placed inside the sample container 16a.
Contains 6 As a result, the protein crystal 18a is filled with the mother liquor atmosphere and is not altered. The size of the protein crystal 18a is about 0.1 mm to several mm.

In order to align the protein crystals 18a with the irradiated X-rays, first, the foil 14 is placed in the collimator and the sample container 1.
6a to the X-ray path. Then, as described with reference to FIG. 1, the enlarged image of the protein crystal 18a is detected by the two-dimensional X-ray detector using the secondary X-rays generated on the foil 14. As this two-dimensional X-ray detector, the detector for diffracted X-ray measurement provided in the X-ray diffractometer can be used as it is. When the enlarged image of the protein crystal is obtained, the sample container 16a is moved so that the center of the enlarged image comes to the center of the two-dimensional X-ray detector. The center of the two-dimensional X-ray detector is
Adjust beforehand so that it is on the extension of the X-ray beam emerging from the collimator. As a result, protein crystal 1
8a is correctly positioned on the X-ray path. In this way, the position of the sample 18 can be confirmed without seeing the inside of the sample container 16a. After the above sample position adjustment is completed, the foil 14 is retracted from the X-ray path, and the X-ray diffraction measurement of the protein crystal is performed.

As the material of the sample container 16a, carbon can be used instead of beryllium described above. When carbon is used, it is preferable to use a material called amorphous carbon.

When the X-ray microscope shown in FIG. 1 is used for confirming the sample position of the X-ray diffraction measuring device, it is not necessary to increase the enlargement magnification so much and it is necessary to pay attention to the blurring of the image. There is no. Therefore, for such sample position confirmation, the inner diameter of the exit hole of the collimator 12 in FIG. 1 may be about 0.2 to 0.5 mm, and the foil 1
The distance a between the sample 4 and the sample 16 may be about 5 mm, for example.
In this case, the distance b between the sample 16 and the two-dimensional X-ray detector 22
Is 100 to 200 mm, the magnification is 20 to 40 times.

As an X-ray diffractometer in which an X-ray microscope can be incorporated, a device equipped with a collimator and a two-dimensional X-ray detector is most suitable. This is because the collimator and the two-dimensional X-ray detector can be used as they are as the components of the X-ray microscope. If an X-ray microscope for confirming the sample position is incorporated in an X-ray diffraction device equipped with a detection system such as a proportional counter, it is necessary to separately provide a two-dimensional X-ray detector for confirming the sample position. .

[0022]

According to the sample position confirmation method of the present invention, the position of the sample is confirmed by utilizing the secondary X-rays generated on the foil, so that the sample inside the sample container cannot be visually observed. , The positional relationship between the sample and the X-ray path can be confirmed. Therefore, the sample container can be manufactured by selecting an optimum material with a small amount of scattered X-rays without being restricted by visible light transmission. Beryllium is the most suitable material for the sample container,
Carbon can also be used.

Further, in the X-ray microscope of the present invention, a foil is placed between the collimator and the sample, and the foil is generated from this foil.
Since the next X-ray is used, it can be used as a sample position confirmation means by incorporating it in an X-ray diffractometer.

Further, in the sample container of the present invention, the sample is hermetically sealed inside the container made of beryllium or carbon, so that the sample which is liable to be deteriorated is kept in the mother liquor atmosphere and scattered from the sample container. With the influence of X-rays reduced, X-ray diffraction measurement with less background can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an X-ray microscope of the present invention.

FIG. 2 is a side view of the X-ray microscope shown in FIG.

FIG. 3 is an enlarged side sectional view of a sample container of an X-ray diffraction apparatus.

[Explanation of symbols]

 10 X-ray source 12 Collimator 14 Foil 16 Sample container 18 Sample 20 Secondary X-ray 22 Two-dimensional X-ray detector

Claims (9)

[Claims] 1. An X-ray diffractometer for irradiating a sample with X-rays that have passed through a collimator and measuring the diffracted X-rays from this sample with a two-dimensional X-ray detector. A foil is inserted in the X-ray path of the foil, the foil is irradiated with X-rays, the sample is irradiated with secondary X-rays emerging from the back surface of the foil, and the foil is transmitted through the sample and its surrounding space. A sample position confirmation method characterized by confirming a positional relationship between the sample and the X-ray path by detecting a secondary X-ray with the two-dimensional X-ray detector. 2. The sample position confirmation method according to claim 1, wherein the material of said foil is amorphous. 3. The sample position confirming method according to claim 1, wherein the sample is hermetically sealed in a container made of beryllium or carbon. 4. The sample position confirming method according to claim 1, wherein the sample is hermetically sealed in a container made of a material that does not transmit visible light. 5. The sample position confirmation method according to any one of claims 1 to 4, wherein the sample is a protein crystal. 6. A sample container for an X-ray diffraction apparatus, wherein a sample is hermetically sealed inside a container made of beryllium. 7. A sample container for an X-ray diffraction apparatus, wherein the sample is hermetically sealed in a container made of carbon. 8. The foil is irradiated with X-rays that have passed through a collimator, and the secondary X-rays emitted from the back surface of the foil are irradiated to a sample arranged in the vicinity of the foil, and the sample and its surroundings. An X-ray microscope characterized in that a magnified image of the sample is obtained by detecting the secondary X-rays that have passed through the space with a two-dimensional X-ray detector apart from the sample. 9. The X-ray microscope according to claim 8, wherein the material of the foil is amorphous.