JP3519208B2 - X-ray small-angle scattering device with vacuum chamber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray small angle scattering device for measuring a change in the intensity of scattered X-rays in a small angle region centered on the optical axis of incident X-rays.

[0002]

2. Description of the Related Art Depending on a substance, scattered X-rays may be generated in a small angle region around the optical axis of the incident X-ray, for example, an angle region of about 0 ° to 5 ° when the substance is irradiated with X-rays. is there. For example, when fine particles of about 10 Å to 1000 Å or a non-uniform region having a density of a size corresponding thereto exist in the substance, diffuse scattering in the incident X-ray direction, so-called central scattering occurs. This central scattering is irrelevant to the internal structure of the particle and spreads as the particle becomes smaller. This scattering exists regardless of whether it is crystalline or amorphous, and the scattering angle or incident X
It is observed in a small angle region where the angle from the optical axis of the line is about 0 ° to 5 °. In addition to the above central scattering in the small angle region, Bragg reflection when the lattice spacing is very large like a protein crystal, and crystalline and amorphous are periodically arranged in a fiber sample. , X-ray diffraction and the like in the case of so-called long-period structure are observed. The X-rays observed in the small angle region, including the central scattering, Bragg reflection and X-ray diffraction as described above, are generally called small angle scattering.

The X-ray small-angle scattering apparatus according to the present invention is an apparatus for measuring such small-angle scattering, and various concrete structures thereof have been conventionally proposed. For example, as one example thereof, a three-slit type X-ray small angle scattering device as shown in FIG. 4 is known. This X-ray small angle scattering device has three slits, a first slit 51, a second slit 52 and a third slit 53.

In this X-ray apparatus, the X-rays radiated and diverged from the X-ray source F are used for the first slit 51 and the second slit 5.
2 is used to form a parallel X-ray beam, and the progress of parasitic scattered X-rays generated in the second slit 52 is monitored by the third slit 5.
The sample S is irradiated with a direct beam of X-rays, which is blocked by 3 and the parasitic scattered X-rays are removed. Thus sample S
When the direct beam is irradiated onto the surface of the sample S, scattered X-rays are generated in a small angle region according to the property of the sample S, and the scattered X-rays expose the planar X-ray detector 54 to scatter the X-rays inside the detector. X-ray latent image corresponding to is formed. After visualizing this X-ray latent image, the internal structure of the sample S is determined by observing the visible image.

[0005]

The important point of the above-mentioned small-angle X-ray scattering device is that the very weak scattering X generated from the sample.
This means that it is necessary to detect X-rays. Therefore, parasitic scattered X-rays generated from each slit and air scattered X-rays generated when the X-rays hit the air reach the X-ray detector 54. That is, it must be reliably prevented. This is because if such unnecessary scattered X-rays are mixed in the scattered X-rays that should be originally detected, the noise component becomes large and accurate measurement cannot be performed.

In order to prevent such deterioration of measurement accuracy, in the conventional small-angle X-ray scattering device, as shown in FIG.
The entire small angle scattering device is stored in the vacuum chamber 55,
Further, the inside of the vacuum chamber 55 is evacuated by an exhaust device to maintain a vacuum state. This vacuum treatment prevents air scattering of X-rays and improves measurement accuracy. However, in this conventional apparatus, since the first slit 51 and the second slit 52 are stored in the vacuum chamber 55, when the slits are exchanged to change the slit width or the positions of the slits are adjusted, Vacuum chamber 55
It was necessary to release the vacuum state in the chamber and then open the vacuum chamber before performing the work.

The present invention has been made in view of the above-mentioned problems, and an X-ray small angle scattering device is provided in which an X-ray optical path is surrounded by a vacuum chamber and kept in a vacuum state.
The purpose is to improve the operability for adjusting work of optical elements such as slits.

[0008]

In order to achieve the above object, an X-ray small-angle scattering apparatus according to the present invention comprises a first slit and a first slit for shaping an X-ray emitted from an X-ray source into a parallel X-ray beam. 2 slits and parasitic scattering X generated in the 2nd slit
An X-ray small angle scattering device having a third slit for guiding a parallel X-ray beam to a sample while preventing the progress of the X-ray, and an X-ray detector for detecting a scattered X-ray to be measured generated from the sample,
A first vacuum chamber arranged between the first slit and the second slit, and a second vacuum chamber arranged between the second slit and the X-ray detector and surrounding the third slit and the sample. It is characterized by having.

In the present invention, almost the entire X-ray optical path from the first slit to the X-ray detector is the first vacuum chamber and the second vacuum chamber.
Since it is surrounded by both the vacuum chambers, the occurrence of air scattering of X-rays can be reliably prevented, and therefore, reliable small-angle scattering measurement can be performed. Moreover, since the first slit and the second slit are arranged outside the vacuum chamber, the slit width changing work and the slit position adjusting work relating to these slits can be performed easily without releasing the vacuum state of the vacuum chamber. Can be done.

By dividing the vacuum chamber into two, attenuation of X-rays by the separated air and X-ray transmission window of the vacuum chamber and parasitic scattering generated at the X-ray passage window of the vacuum chamber. There is concern about X-rays, but there is no practical problem with these as follows.

First, the parasitic slit X-rays generated in the X-ray passing window of the vacuum chamber located in front of the second slit are blocked by the second slit. The parasitic slit X-rays generated in the X-ray passing window of the vacuum chamber located behind the second slit are blocked by the third slit. Therefore, when the vacuum chamber is divided, the measurement accuracy does not deteriorate due to the parasitic scattered X-rays generated at the divided position.

Further, the attenuation of X-rays caused by the X-ray passage window of the air and the vacuum chamber can be considered as follows. For example, considering that an X-ray passage window is formed by stacking two 12.7 μm-thick polyimide films and an air path with a length of 1 cm is formed at the dividing position of the vacuum chamber, the X-ray passage window is formed. X-ray transmission rate at window = 97.8% X-ray transmission rate of air = I / I ₀ = exp ^{(−u · t)} = 98.8
However, u: linear absorption coefficient = 0.01195 cm ^-1 t: air path length = 1 cm, therefore the total of X-ray transmittance by air and window is
96.63%, so the attenuation of X-rays by air and windows is 3.37%. It is considered that this value does not matter in practical use.

In the above X-ray small angle scattering device, it is desirable that the X-ray detector is a linear X-ray detector or a planar X-ray detector. The linear X-ray detector is an X-ray detector of a type capable of detecting X-rays within a linear range. For example, PSPC (Position Sensitive Proportional Co
unter: position sensitive X-ray detector) is considered.

Since this PSPC is well known in itself, a detailed description thereof will be omitted, but if an example thereof is briefly explained, as shown in FIG. 3, the anode line 31, the cathode line 32 and the delay line 33 are internally provided. Have. When X-rays enter the PSPC 35 through the X-ray capturing window 34, charges are induced in the cathode line 32, and electric signals corresponding to the charges appear at both ends of the delay line 33. Then, the X-ray is detected by measuring the signal. The signals appearing at both ends of the delay line 33 have a time difference proportional to the distance in the length direction x. Therefore, the X-ray incident position in the length direction x can be known by measuring the time difference between the signals generated at both ends of the delay line 33. That is, the PSPC 35 has the PSP at each position in the length direction x, that is, the scattering angle direction 2θ within the range in which the anode wire 31 and the like are stretched.
The intensity and angular position of each X-ray incident on C35 are detected almost simultaneously.

The flat X-ray detector is an X-ray detector of a type capable of detecting X-rays within a planar range, and examples thereof include an X-ray film and a stimulable phosphor. X
As is well known, a line film is a film capable of being exposed to X-rays to form a latent image on that portion, and developing the latent image into a visible image.

On the other hand, the stimulable phosphor is a sensitizer for X-rays, which is also called a stimulable phosphor, and can store radiation such as X-rays in the form of energy, and further, for example, laser light. It is an object that has the property of being able to emit its energy as light when irradiated with stimulated excitation light.
That is, when the stimulable phosphor is irradiated with radiation such as X-rays, energy is accumulated as a latent image in the stimulable phosphor corresponding to the irradiated portion, and the stimulable phosphor is further stimulated by laser light. When the excitation light is irradiated, the latent image energy becomes light and is emitted to the outside. By detecting the emitted light with a photoelectric tube or the like, it is possible to measure the diffraction angle and the intensity of the X-ray that contributed to the formation of the latent image.

As the X-ray detector, in addition to the linear X-ray detector or the planar X-ray detector described above, a dot-shaped detector such as a scintillation counter which detects X-rays within a narrow dot-shaped range. X-ray detectors are also known. When the point X-ray detector is used, the point X-ray detector is moved within the X-ray diffraction angle range to be measured.

In the present invention, the X-ray passing window of the second vacuum chamber is located at the rear of the second slit with respect to the X-ray source. The parasitic scattered X-rays generated in the X-ray passing window are blocked by the third slit. In this case, the smaller the distance between the X-ray passing window and the third slit, the wider the range of parasitic scattered X-rays that reach the X-ray detector. Therefore, the distance between the X-ray passing window and the third slit is as large as possible, in other words, the X-ray passing window is arranged at a position as close as possible to the second slit, that is, in contact with or close to it. It is desirable to provide it.

In the present invention, since the first slit and the second slit are arranged outside the first vacuum chamber and the second vacuum chamber, adjustments relating to those slits can be easily performed without releasing the vacuum. it can. In many cases, adjusting these slits provides the desired measurement conditions. However, in some cases, it may be preferable to change the slit width for the third slit as well. In consideration of such a case, it is desirable to provide slit width adjusting means capable of adjusting the slit width of the third slit from the outside of the second vacuum chamber.

In a general small-angle X-ray scattering apparatus, the arrangement positions of the first slit and the second slit and the distance between the first slit and the second slit may be changed. In order to deal with such a case, it is desirable to provide slit position adjusting means for changing the installation positions of the first slit, the second slit and the first vacuum chamber on the X-ray optical axis.

[0021]

1 shows an embodiment of an X-ray small angle scattering device according to the present invention. This X-ray small-angle scattering device includes an X-ray source F that generates X-rays, and a slit unit 9 that includes a first slit 1 and a second slit 2.
And a third slit 3 arranged on the downstream side (right side in the drawing) of the slit unit 9, and an X-ray detector 4 arranged on the downstream side of the third slit 3.

The sample S to be measured is the third slit 3
And the X-ray detector 4 are arranged. Further, in the present embodiment, as the X-ray detector 4, a planar X-ray detector capable of capturing X-rays in a plane, for example, a stimulable phosphor is used. The slit shapes of the first slit 1, the second slit 2, and the third slit 3 are round holes or rectangles depending on the measurement conditions.

In FIG. 1, the first slit 1 is supported by a dedicated slit support member 5a, and the second slit 2
Are supported by a dedicated slit support member 5b. Each of the slits 1 and 2 is attachable to and detachable from each of the slit support members 5a and 5b. As the measurement conditions change, the slits with appropriate dimensions are replaced and used.

A first vacuum chamber 11a is arranged between the first slit 1 and the second slit 2, and the second slit 2
The second vacuum chamber 11b is arranged between the X-ray detector 4 and the X-ray detector 4. The interior of each chamber is airtightly isolated from the outside, and an exhaust device 12 such as a vacuum pump is provided.
The inside is kept in a vacuum state by. An X-ray passing window 13 is provided on the X-ray optical axis R of each chamber 11a and 11b. These windows 13 are formed by forming openings in each chamber and airtightly shielding the openings with an X-ray transmitting member.

The X-ray transmitting member can be formed of beryllium (Be) film, polyimide film or the like. As the polyimide film, for example, a film provided by Toray DuPont Co., Ltd. under the trade name “Kapton” can be used. X of the second vacuum chamber 11b
The X-ray passage window 13x adjacent to the X-ray detector 4 has a large area for guiding scattered X-rays from the sample S to the X-ray detector 4 in a wide range. At the front position of the X-ray detector 4, a direct beam stopper 1 for preventing the direct beam from the X-ray source F from reaching the X-ray detector 4.
4 are provided.

As shown in FIG. 2, the third slit 3 is defined by a vertical slit piece 15a and a horizontal slit piece 15b. An adjustment knob 17 having a screw shaft 16 is provided on the side wall of the second vacuum chamber 11b, and these screw shafts 16 serve as the vertical slit pieces 15a and the horizontal slit pieces 15 respectively.
Screw with b. By appropriately turning one or both of the two adjusting knobs 17, the vertical slit pieces 15a and / or
Alternatively, the horizontal slit piece 15b can be moved in parallel,
Thereby, the slit width of the third slit 3 can be adjusted to a desired dimension. That is, the slit width adjusting device 20 for adjusting the slit width is configured by the adjusting knob 17 that is screw-fitted to the slit pieces 15a and 15b.

Returning to FIG. 1, a slit position adjusting device 18 is provided outside the first vacuum chamber 11a. The slit position adjusting device 18 includes a rail 19 provided in parallel with the X-ray optical axis R, and three moving bodies 21 that are guided and moved by the rail. Each moving body 21 includes a slit support member 5a that supports the first slit 1, a first vacuum chamber 11a, and a second vacuum chamber 11a.
It is connected to a slit support member 5b that supports the slit 2. If each moving body 21 is moved along the rail 19 by an appropriate distance, the first slit 1 and the second slit 2 can be placed at desired desired positions on the X-ray optical axis R. The spacing between the slits can be varied.

Since the X-ray small angle scattering device of the present embodiment is constructed as described above, the exhaust device 12 is shown in FIG.
Thus, the insides of the first vacuum chamber 11a and the second vacuum chamber 11b are evacuated and kept in a vacuum state. In this state, the X-rays emitted from the X-ray source F and diverging are
The slit unit 9 including the slit 1 and the second slit 2 forms a parallel X-ray beam, and the parallel X-ray beam is incident on the sample S. Then, scattered X-rays are generated from the sample S according to the property of the sample S, the scattered X-rays reach the X-ray detector 4 and are exposed to the light, and a latent image is formed on the exposed portion. In the present embodiment, since the X-ray detector 4 is composed of a stimulable phosphor, an energy latent image is formed inside the X-ray detector 4 at the portion where the scattered X-rays hit.

Scattering X from the sample S on the X-ray detector 4
After the radiation irradiation work is completed, the X-ray detector 4 is carried to a predetermined reading stage, and stimulated excitation light such as laser light is emitted to the X-ray detector 4. Then, the X-ray detector 4
The energy latent image accumulated inside the unit emits light to the outside, and the emitted light is read by a photoelectric converter or the like to measure the scattering angle and the X-ray intensity of the scattered X-rays. The scattering angle is the angle 2θ with reference to the X-ray optical axis R in FIG.

In the above measurement, the X-ray optical path from the first slit 1 to the X-ray detector 4 is kept in a vacuum state by the first vacuum chamber 11a and the second vacuum chamber 11b, so that the X-ray optical path is kept on the X-ray optical path. Air scattered X-rays are not generated around the advancing X-rays, and therefore scattered X-rays generated from the sample S can be detected with high accuracy. When it is necessary to change the slit width of the first slit 1 and / or the second slit 2 in order to change the measurement condition, the slit having the desired slit width is replaced with the slit support member 5a and / or the slit support member 5b. . Further, when it is necessary to change the inter-slit distance between the first slit 1 and the second slit 2, the moving body 21 corresponding to each slit is moved along the rail 19. These operations are the first
Since the operation can be performed without releasing the vacuum state in the vacuum chamber 11a and the second vacuum chamber 11b, the work can be easily performed in a short time.

When it is necessary to change the slit width of the third slit 3, either one of the two adjusting knobs 17 is selected in FIG. 2 or both of them are set at an appropriate angle. The slit pieces 15a and 15b are rotated to move in parallel, whereby the slit width of the third slit 3 is adjusted. Also in this case, the second vacuum chamber 11b
There is no need to release the vacuum inside.

In FIG. 1, the X-ray passage window 13Y on the side closer to the second slit 2 of the second vacuum chamber 11b generates parasitic scattered X-rays when the X-rays strike it. The progress of this parasitic scattered ray is blocked by the third slit 3, but the parasitic scattered X-ray that reaches the central portion indicated by the symbol E with respect to the X-ray detector 4 cannot be blocked. That is, the range of the X-ray image that can be the target of determination without including the noise component due to the parasitic scattered X-ray is the range outside the central portion E.

Unmeasurable range E including this parasitic scattered X-ray
Becomes wider as the arrangement position of the X-ray passing window 13Y gets closer to the third slit 3. Therefore, the X-ray passing window 1
3Y is a position as far away from the third slit 3 as possible,
In the case of this embodiment, it is desirable to dispose the second slit 2 at a position as close as possible. In the present embodiment, since the second slit 2 is attached to the slit support member 5b, X
It may not be possible to directly contact the line passing window 13Y with the second slit 2, and it may be that the line supporting window 13Y is brought into contact with the slit supporting member 5b at a position closest to the second slit 2.

The present invention has been described above based on the preferred embodiments, but the present invention is not limited to the embodiments and can be variously modified within the scope of the invention described in the claims. For example, the X-ray detector is not limited to a flat X-ray detector such as a stimulable phosphor, but a point X-ray detector such as a scintillation counter or a linear X-ray detector such as PSPC.
A line detector can also be used.

A slit width adjusting device 2 for adjusting the slit width of the third slit from the outside of the vacuum chamber.
0 and the slit position adjusting device 18 for adjusting the arrangement positions of the first slit 1 and the second slit 2 do not necessarily have to be provided. Further, their specific structure is not limited to the structure shown in FIG.

[0036]

According to the X-ray small angle scattering device of the first aspect, since the first slit and the second slit are arranged outside the vacuum chamber, the work of changing the slit width and the slit position of those slits are performed. The adjustment operation can be easily performed without breaking the vacuum state in the vacuum chamber.

According to the X-ray small-angle scattering apparatus of the second aspect, the measurement is performed with the X-ray detector fixed.
The second vacuum chamber can also be fixedly installed. On the other hand, when the point X-ray detector is used, since it is necessary to move the X-ray detector in the X-ray diffraction angle direction, it may be necessary to move the vacuum chamber correspondingly. Therefore, if a linear X-ray detector or a planar X-ray detector is used,
The structure related to the vacuum chamber can be simplified.

According to the X-ray small-angle scattering apparatus of the third aspect, in the range where the X-ray can be detected by the X-ray detector,
It is possible to widen the range that can be the target of determination without being disturbed by the parasitic scattered X-rays.

According to the X-ray small angle scattering device of the fourth aspect, the slit width of the third slit can be adjusted without releasing the vacuum in the vacuum chamber.

According to the X-ray small-angle scattering device of the fifth aspect, regarding the first slit and the second slit, the gap between slits is changed in addition to the change of the slit width without releasing the vacuum state in the vacuum chamber. It is also possible to adjust

[0041]

[Brief description of drawings]

FIG. 1 is a side sectional view schematically showing an embodiment of an X-ray small-angle scattering device according to the present invention.

FIG. 2 is a front sectional view showing a main part of the apparatus shown in FIG.

FIG. 3 is a perspective view showing another example of an X-ray detector.

FIG. 4 is a side sectional view showing an example of a conventional small-angle X-ray scattering device.

[Explanation of symbols]

1st slit 2 second slit 3rd slit 4 X-ray detector 5a, 5b Slit support member 9 slit unit 11a, 11b vacuum chamber 13 X-ray passing window 14 Direct beam stopper 15a, 15b slit pieces 16 screw shaft 17 Adjustment knob 18 Slit position adjustment device 19 rails 20 Slit width adjustment device 21 moving body 34 X-ray acquisition window 35 PSPC F X-ray source S sample R X-ray optical axis

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-130002 (JP, A) Actual Kaihei 5-81699 (JP, U) Actual public Sho 35-30595 (JP, Y1) Actual public 35- 30596 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 23 / 00-23 / 227

Claims (5)

(57) [Claims] 1. A first slit and a second slit for shaping an X-ray emitted from an X-ray source into a parallel X-ray beam, and a second slit.
Small-angle X-ray scattering having a third slit that guides a parallel X-ray beam to a sample while blocking the progress of parasitic scattered X-rays generated at the slit, and an X-ray detector that detects the scattered X-rays to be measured generated from the sample In the apparatus, a first vacuum chamber provided between the first slit and the second slit, and a second vacuum chamber provided between the second slit and the X-ray detector and surrounding the third slit and the sample. A small-angle X-ray scattering device having a vacuum chamber. 2. The X-ray small-angle scattering device according to claim 1, wherein the X-ray detector is a linear X-ray detector or a planar X-ray detector. 3. The X-ray small-angle scattering device according to claim 1, wherein the second vacuum chamber is in contact with or close to the second slit. 4. The X-ray small-angle scattering device according to claim 1, further comprising slit width adjusting means for adjusting the slit width of the third slit from the outside of the second vacuum chamber. An X-ray small-angle scattering device characterized by being provided. 5. The X-ray small angle scattering device according to claim 1, wherein the installation positions of the first slit, the second slit and the first vacuum chamber are on the X-ray optical axis. An X-ray small-angle scattering device having slit position adjusting means for changing the angle.