JPH095499A - Soft x-ray micrscope - Google Patents

Abstract

PURPOSE: To provide a soft X-ray microscope capable of observing the internal structure of a material as it is without evaporating the moisture contained in the material to be measured. CONSTITUTION: This soft X-ray microscope 1 is provided with a laser generating means 2 and a vacuum container 3 having a target 4 for generating soft X-rays 40 and a soft X-ray detecting means for detecting the soft X-rays 40 passing a measured material. The vacuum container 3 is provided with a target storage space 3a strong the target 4 and a storage space for material to be measured 3b strong the material to be measured, and the degree of vacuum of the material storage space 3b is made lower than the degree of vacuum of the target storage space 3a.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a soft X-ray microscope.

[0002]

2. Description of the Related Art A laser irradiation type soft X-ray microscope, which has been developed in recent years, is a soft X-ray microscope that transmits a laser generating means, a target for generating soft X-rays, and a material to be measured.
And a vacuum container having a soft X-ray detecting means for detecting the X-ray. This soft X-ray microscope obtains a laser plasma soft X-ray light source by focusing laser light from a laser generating means on a target in a state where the inside of a vacuum container is depressurized to a predetermined degree of vacuum.

The soft X-ray generated from this light source is
By irradiating the material to be measured and detecting the difference in the soft X-ray transmittance due to the difference in the internal composition of the material to be measured by the soft X-ray detecting means, the internal tissue can be observed.

[0004]

However, since the soft X-ray microscope generates soft X-rays when the vacuum container is depressurized when it is used, the soft X-ray microscope can be used as an observation target such as water and other substances. Liquid (hereinafter referred to as water)
In the case of using a material to be measured that contains, if the degree of vacuum due to the reduced pressure is high, water or the like evaporates and it is not possible to observe accurately.

An object of the present invention is to provide a soft X-ray microscope capable of observing the internal structure as it is without evaporating the water content contained in the material to be measured.

[0006]

Therefore, the inventor of the present invention can efficiently convert the laser light on the way from the laser generating means to the target into the soft X-ray in the vacuum container without attenuating the laser light. At the same time, the inventors have completed the invention by discovering a configuration that allows observation without evaporating water even when a material to be measured containing water is used.

A soft X-ray microscope of the first invention is a vacuum having a laser generating means, a target for generating soft X-rays, and a soft X-ray detecting means for detecting soft X-rays transmitted through a material to be measured. A soft X-ray microscope having a container, wherein the vacuum container has a target accommodation space for accommodating the target and a measured material accommodation space for accommodating the measured material, and the measured material accommodation space The degree of vacuum of is lower than the degree of vacuum of the target accommodation space.

The soft X-ray microscope of the second invention is provided with a condensing optical device for accommodating a condensing optical system between the target accommodating space and the measured material accommodating space in the soft X-ray microscope of the first invention. Is characterized by. The target accommodating space and the measured material accommodating space are two spaces formed by dividing the interior of the vacuum container into two by a partition wall having small holes, or two containers arranged inside the vacuum container and independent from each other. It is possible to use a structure in which the small holes are communicated with each other.

The small hole has a function as a passage through which the soft X-rays generated in the target can be radiated from the target accommodation space to the measurement target material installed in the measurement target material accommodation space and the target accommodation space decompressed by the vacuum pump. A function as a diaphragm that limits the amount of atmospheric gas introduced into the measured material accommodation space and maintains a predetermined degree of vacuum, and that maintains the measured material accommodation space at a degree of vacuum lower than that of the target accommodation space. With. The shape and size of this small hole can be variously set. As the shape of the small holes, for example, soft X
A cone, a pyramid, etc., whose diameter increases in the direction of travel of the line, or a circular shape when viewed from the side of the space under measurement,
It may be rectangular, oval, or the like. The size of the small holes is 0.1 mm (about 100 cm ³ ) to 1
What is set in the range of 00 mm (about 100 m ³ ) can be used. The thickness of the partition wall forming the small holes may be 0.1 to 100 mm.

The degree of vacuum in the target accommodating space is such that the laser beam focused on the target by the laser generating means is not absorbed or attenuated during the process, or the absorption or attenuation can be reduced, and the softness required by the focusing is required. X-rays should be generated. For example, the degree of vacuum in the target housing space may be a pressure smaller than 20000 Pa using helium gas. This degree of vacuum is obtained by exhausting the atmospheric gas in the target housing space by a vacuum pump (rotary pump or the like) to reduce the pressure and controlling the exhaust amount while measuring with a vacuum gauge (Pirani vacuum gauge or the like).

The degree of vacuum in the space for containing the material to be measured is lower than the degree of vacuum in the space for containing the target, and there is no evaporation of water or the like in the material to be measured, or the evaporation can be reduced, and the material does not contain water. The material to be measured can be observed. When a living thing is used as the material to be measured, air for observing while maintaining its living state is required, and a pressure of at least 50,000 Pa is required. This low degree of vacuum is an atmosphere that communicates with the measured material storage space while exhausting the measured material storage space through a small hole that communicates with the target storage space and measuring with a vacuum gauge (Pirani vacuum gauge, etc.). The amount of the atmospheric gas introduced from the gas introduction passage can be obtained by controlling the leak valve and the opening / closing valve. The atmosphere gas is
Atmosphere, helium gas, hydrogen, etc. can be used.

The target accommodating space has laser light incidence means for introducing the laser light generated by the laser generation means therein. Laser light incidence means
A vacuum window and a condenser lens are used, which are attached to the peripheral wall that constitutes the target housing space and face perpendicularly to the central axis of the laser light. The laser generation means is installed outside the vacuum container, and the laser light incidence means (vacuum window,
Laser light can be applied to the target in the target housing space via a condenser lens () and the target is 10 ⁹ W / cm ²
There is no particular limitation as long as it is a laser generator capable of obtaining a soft X-ray light source with the ability to collect light at the above energy density, and examples thereof include a YAG laser, a gas laser,
An excimer laser, a carbon dioxide laser, etc. can be used.

The soft X-rays have a wavelength range of about 0.1 to several tens of nm. Any target can be used as long as it can generate a soft X-ray having a wavelength that can be transmitted through the material to be measured and can be detected as a difference in transmittance due to a difference in internal composition when the laser light is irradiated and focused. For example, wavelength 4n
iron, silicon, graphite, magnesium, aluminum, titanium, manganese, which generates soft X-rays of m or more,
Nickel, cobalt, copper, zinc, germanium or the like can be used.

The target is held by a holding device such as a chuck provided in the target accommodation space. As the holding device, one having a mechanism capable of rotating the target is used, and one capable of displacing a portion (spot) region where the laser light from the laser generating means is focused on the target is preferably used. As the material to be measured, a material containing or adhering water or a liquid other than water, for example, a living organism containing water, human DNA, uncured polymer (including water or an organic solvent in a film-forming process) A coating film at the curing stage) or the like can be used.

The thickness of the material to be measured is from sub μm to several 1
It is preferable to use one having a thickness of 0 μm. The reason for this is that if the thickness of the material to be measured is less than sub-μm, it is difficult to obtain contrast due to the difference in structure (type of element or density), and conversely, if it exceeds several tens of μm, the transmission amount of soft X-rays is generally low. This is because the tissue becomes less visible and the tissue becomes difficult to see. Soft X
The line detection means is not particularly limited as long as it is a member or device having a spatial resolution necessary for analyzing the material to be measured and having sensitivity to soft X-rays having a wavelength of 1 to 80 nm, for example, a resist, Soft X-ray dry plate, soft X-ray film or solid X-ray detector (MC with X-ray photocathode
P, CCD, zooming tube, etc.) can be used.

The soft X-ray detecting means may be installed together with the measured material in the measured material accommodation space, or may be installed in a soft X-ray detecting means accommodation space provided separately behind the measured material accommodation space.
The condensing optical device is provided between the measured material accommodation space and the target accommodation space and has a condensing optical system. As the condensing optical system, for example, a Fresnel zone plate, a spheroid mirror, or the like can be used. By using the condensing optical system, the light can be efficiently focused on the soft X-ray detection means (the area for analyzing the soft X-rays that have passed through the material to be measured), and therefore the soft X-ray detection power can be increased. Soft X that collects X-rays
The distance between the line detecting means and the soft X-ray light source (point) on the target can be set large. In this case, the material to be measured and the soft X due to the blast (the blast is a phenomenon in which the substance forming the target becomes fine particles that evaporate and the fine particles damage the material to be measured) caused by laser irradiation to the target. There are advantages such as preventing damage to the line detection means.

[0017]

According to the soft X-ray microscope of the first invention,
The target and the measured material are separately accommodated in the measured material accommodation space and the target accommodation space of the vacuum container. Moreover,
The vacuum degree of the measured material accommodation space that accommodates the measured material is set to be lower than the vacuum degree of the target accommodation space that accommodates the target. Therefore, for example, the material to be measured containing water or the like does not have to be affected by the reduced pressure, so that the water or the like is not evaporated.

On the other hand, the target accommodating space does not accommodate the material to be measured containing the moisture and the like, so that the degree of vacuum can be set high. Therefore, the atmosphere gas in the target accommodation space can be made lean, and the laser light on the way to the target from the laser generating means is hardly absorbed and attenuated by the atmosphere gas, so that it can be sufficiently collected on the focused portion on the target. Various energy can be applied, and the required laser plasma soft X-ray light source can be obtained.

At the same time, the soft X-ray generated from the soft X-ray light source
The line is applied to the material to be measured. This soft X-ray passes through the material to be measured, and the difference in transmittance due to the difference in the internal composition of the material to be measured is detected by the soft X-ray detecting means. Therefore, according to the soft X-ray microscope of the first aspect of the present invention, even when the material to be measured containing water or the like is used, the vacuum degree of the material to be measured accommodating space for accommodating the material to be measured is equal to that of the target accommodating space. Since it is set lower than the vacuum degree, it is possible to accurately observe the internal tissue as it is without evaporating water and the like.

By using the soft X-ray microscope according to the first aspect of the present invention, it is possible to observe, for example, organisms and the process of forming a coating film before drying. Further, since the laser plasma soft X-ray light source that generates the soft X-rays is a pulse light source of several nsec, by utilizing this time resolution, for example, in a state in which the high-speed rotation of the flagella of the dynamic bacteria is stopped. It is also possible to observe.

That is, the flagella of the bacterium rotates at a high speed (about 200 rotations / second), but since it is a pulsed light source of several nsec, it is a sufficiently short time (about 10 ⁻⁸ seconds) as compared with the rotational movement of the flagella. ), And can be observed with the movement almost stopped. According to the soft X-ray microscope of the second aspect of the invention, since the condensing optical device that accommodates the condensing optical system is provided between the target accommodation space and the measured material accommodation space, the target accommodation space and the measured material accommodation space. Even if the difference in the degree of vacuum between and is large, the respective degrees of vacuum can be stably maintained.

In addition, the condensing optical system housed in the condensing optical device transmits the material to be measured by the soft X-ray detecting means in order to increase the irradiation intensity of soft X-rays on the way from the target to the material to be measured. The soft X-ray detection time can be shortened. Further, the distance between the soft X-ray detecting means for condensing the soft X-rays and the soft X-ray light source on the target can be set large, so that the material to be measured and the soft X-ray detecting means by the blast generated by the laser irradiation to the target. Can prevent damage.

In order to confirm the action and effect of the invention, the inventor seeks the possibility of observing the internal structure as it is without evaporating the water content contained in the material to be measured. A comparative experiment was conducted in which an appropriate amount of atmospheric gas was introduced into the vacuum container to raise the pressure and reduce the degree of vacuum. That is, the atmosphere is used as the atmospheric gas, carbon is used as the target, the distance between the target and the soft X-ray detecting means is set to 0.91 m, and the soft X-ray reaching the soft X-ray detecting means is photographed with 1024 shots. And analyzed.

As a result, as shown in FIG.
Although the spectrum intensity decreased as the pressure was increased to 00 Pa and 1000 Pa, the spectrum could be observed up to 1000 Pa. However, at 4000 Pa (not shown), the intensity of the spectrum was further reduced to be below the display range of FIG. 9, and the spectrum could not be observed. Further, soft X-rays were photographed in 1024 shots and analyzed under the same conditions as described above except that helium gas was used as the atmosphere gas.

As a result, as shown in FIG. 10, 40 Pa,
Although the spectrum intensity decreased as the pressure was increased to 4000 Pa and 20000 Pa, the spectrum could be observed up to 20000 Pa. However, 1 atm
When it was (1.01325 × 10 ⁵ Pa (not shown)), the intensity of the spectrum was further lowered to fall below the display range of FIG. 10, and the spectrum could not be observed.

From these results, the atmospheric gas in the vacuum container absorbs and attenuates the laser light on its way to the target from the laser generating means, so that a plasma state cannot be obtained at the laser light condensing portion on the target. It turned out that the required soft X-rays cannot be generated. The reason why the soft X-ray spectrum obtained by the above experiment cannot be observed is as follows.
Assuming that the soft X-rays are absorbed by the atmospheric gas, the calculated value of the transmittance of the soft X-rays in the atmospheric gas (40 Pa, 400 P in the atmospheric atmosphere shown in FIG. 11).
a, soft X-ray transmittance of 1000 Pa, 4000 Pa) (40 Pa, 40 under helium gas atmosphere shown in FIG. 12)
00Pa, 20000Pa, 1atm soft X-ray transmittance)
It is thought that this is because the attenuation is greater than

In FIG. 11, soft X-rays in the wavelength range of 3.1 to 4 nm are compared with FIG. 9 of Experimental Example 1. FIG. 12 compares soft X-rays in the wavelength region of 2.5 to 4 nm with FIG. 10 of Experimental Example 2. The respective wavelength regions used for the comparison are affected by higher-order light by a diffraction grating such as second-order light and third-order light (when dispersed by the diffraction grating, for example, 5 nm at a position of 5 nm).
It is a wavelength region in which higher-order lights such as / 2 nm and 5/3 nm do not overlap little by little).

The difference due to the comparison is that the soft X
Not because the soft X-rays are attenuated on the way to the line detection means, but the laser light on the way to the target from the laser generation means is absorbed and attenuated by the atmospheric gas, and carbon plasma is not sufficiently generated on the target. It is thought to be because. Further, even if the soft X-ray has a low intensity, it can be put to practical use by increasing the number of shots.
For example, when using soft X-rays with a wavelength of 4.4 nm and observing at 1000 Pa in a helium gas atmosphere with a distance between the target and the soft X-ray detecting means set to 0.91 m, the number of shots of laser light is 400 Pa more than that in the case of 400 Pa. It can be put to practical use by increasing it by about 10 times.

Further, the number of shots can be kept less than the above case by shortening the distance between the target and the soft X-ray detecting means to less than 0.91 m. However, when it is set to 4000 Pa in the air atmosphere, it cannot be used because soft X-rays are not generated. On the other hand, the diameter of the irradiation mark (focusing point) by the laser beam on the target is 400 μm with almost no change when the pressure is changed from 40 Pa to 20000 Pa in the helium gas atmosphere, and the atmospheric pressure (about 100,000 Pa)
In that case, the irradiation mark was very small, about 100 μm.

Therefore, when the atmospheric pressure is set in the helium gas atmosphere, the helium gas absorbs and attenuates the laser light on the way from the laser generating means to the target, so that a plasma state cannot be obtained on the target, which is necessary. Soft X
Cannot generate lines. The absorption of soft X-rays (on the way from the target to the soft X-ray detection means) does not pose a practical problem.

[0031]

【Example】

(Embodiment 1) As a first embodiment of a soft X-ray microscope of the present invention, a case of application to a contact type soft X-ray microscope will be described with reference to FIGS. The soft X-ray microscope 1 shown in FIG. 1 is a YA as a laser generating means.
It comprises a G laser device 2 and a vacuum container 3.

The YAG laser device 2 is installed outside the vacuum container 3 and can irradiate the inside of the vacuum container 3 with a laser beam 20 having an energy of 0.4 joule (J) and a pulse width of 8 nanoseconds (ns). Has performance. The vacuum container 3 is
A substantially rectangular box-shaped body, which is formed by partitioning the peripheral wall portion 30, a partition wall portion 32 provided with small holes 31, and the interior surrounded by the partition wall portion 32 into two parts. The storage space 3a and the measured material storage space 3b are provided.

The shape and size of the small hole 31 provided in the partition wall 32 is set to a circular shape of 0.5 mm. The target accommodation space 3a is attached to the peripheral wall portion 30,
A vacuum window 33 and a condenser lens 34 for transmitting the laser beam 20 emitted from the G laser device 2, and a soft X-ray 40.
And a rotation device 5 for fixing and holding the target 4 at a predetermined position in a rotatable manner.
And a vacuum pump 6 and a first Pirani vacuum gauge (not shown).

In the target housing space 3a, the target 4 can be installed and taken out and can be airtightly maintained by opening and closing a first opening / closing lid member (not shown) provided on the peripheral wall portion 30. The condensing lens 34 condenses the laser light 20 and can irradiate the condensing diameter (diameter) on the target 4 with a value of 40 to 80 μm or less, and the irradiation intensity of the laser light 20 on the target 4 is 10 ^{11-10 13}
W / cm ² (a value that takes into consideration the surface reflection by the vacuum window 33 and the condenser lens 34) is obtained.

The target 4 is an iron φ8 mm round bar and is attached to the rotary holding shaft 50 of the rotating device 5 by the chuck 51. When the laser beam 20 is focused, soft X-rays having a wavelength of 4 to 40 nm are used. Can occur. The target 4 is able to rotate and change the position of the portion corresponding to the focusing position of the laser light 20 together with the rotation holding shaft portion 50 at a predetermined time interval, and always focus on a new surface portion.

A rotary pump is used as the vacuum pump 6. The vacuum pump 6 has a performance of reducing the pressure of the target housing space 3a to a predetermined degree of vacuum, and specifically,
The maximum flow rate can be set to 1000 Pa in consideration of the flow rate of the helium gas introduced from the measured material accommodation space 3b through the small hole 31 of the holding partition wall portion 32. The first Pirani vacuum gauge can measure the degree of vacuum in the target housing space 3a when the vacuum pump 6 depressurizes the target housing space 3a.

In the material storage space 3b to be measured, a soft X-ray camera 7 equipped with a soft X-ray dry plate (not shown, the same applies hereinafter) as a soft X-ray detecting means, and a control valve 80 for introducing helium gas. And a second Pirani vacuum gauge (not shown). Further, the measured material accommodation space 3b is formed by the peripheral wall portion 3
By opening and closing a second opening / closing lid member (not shown) provided on the No. 0, the camera 7 can be installed and taken out and can be kept airtight.

When the camera 7 is used, a material to be measured (not shown) and a dry X-ray dry plate in which the material to be measured are brought into close contact are loaded inside the camera 7, and then the holding member 70 is used to store the material to be measured 3b. It is fixedly held in place. The gas introduction passage 8 is
One end is connected to a helium gas supply source 81 (not shown), and the other end is connected to the measured material accommodation space 3b. The gas introduction passage 8 is
It can be opened and closed by operating the control valve 80, and helium gas can be introduced from the helium gas supply source 81 into the measured material accommodation space 3 according to the opening degree when the control valve 80 is opened. Second
The Pirani vacuum gauge has a gas introduction passage 8 by a control valve 80.
The vacuum degree of the operation target material accommodation space 3b can be measured at the time of the opening operation.

In the case of using the soft X-ray microscope 1 of Example 1 configured as described above, first, for the soft X-rays, a wing of a dovetail containing water is used as the material to be measured, and the material is adhered to the material to be measured. A camera 7 equipped with a dry plate was prepared. This camera 7
The holding member 70 fixes and holds the measured material accommodation space 3b at a predetermined position, so that the measured material accommodation space 3b is hermetically held.

Then, the control valve 80 is opened to a predetermined opening degree, the helium gas of the supply source 81 is introduced into the measured material accommodating space 3b from the gas introduction passage 8, and at the same time, the vacuum pump 6 is operated to set the target. The storage space 3a is sucked and the pressure is reduced. At this time, the degree of vacuum in the target accommodation space 3a and the material-to-be-measured accommodation space 3b is not shown in the drawings.
The balance between the suction amount by the vacuum pump 6 and the introduction amount of helium gas by the control valve 80 is controlled while measuring with the Pirani vacuum gauge.

That is, the degree of vacuum of the material-receiving space 3b is determined by the amount of helium gas introduced through the gas introduction passage 8,
From the small hole 31 of the partition wall portion 32 to the target accommodation space 3a
The balance with the amount of helium gas that is sucked in and discharged to the outside is controlled by the size of the opening of the control valve 80. Further, the degree of vacuum of the target accommodation space 3a is determined by the amount of helium gas introduced through the small holes 31 of the partition wall portion 32,
The balance with the amount of helium gas sucked and discharged by the vacuum pump 6 is controlled by the magnitude of the suction force of the vacuum pump 6.

The degree of vacuum in the target accommodation space 3a is 10
It is fixed at 000Pa. This vacuum is 2 laser light
The absorption and the attenuation of 0 are almost suppressed, and for the target 4,
It is a value that can be irradiated with the laser light 20 required to generate the target soft X-ray (see FIG. 10). In addition, the material-to-be-measured accommodation space 3b is maintained at 1 atm. In this state, laser light 20 having an energy of 0.4 joule (J) and a pulse width of 8 nanoseconds (ns) is emitted from the YAG laser device 2.
Is irradiated. The laser light 20 enters through the vacuum window 33 and is condensed on the target 4 by the condenser lens 34.
Then, laser plasma soft X-rays (hereinafter referred to as soft X-rays) are generated on the target 4.

This soft X-ray is emitted from the target accommodation space 3a to the soft X-ray camera 7 in the measured material accommodation space 3b through the small hole 31 of the partition wall portion 32. Then camera 7
Image of the wing of a winged ant containing water (see Fig. 4)
Is recorded and recorded on the soft X-ray dry plate with 128 shots.
After that, the camera 7 is taken out from the measured material accommodation space 3b to the outside, and is subjected to observation by developing the photographed dry X-ray dry plate.

Therefore, according to the soft X-ray microscope 1 of Example 1, even when a wing of a dove containing water is used as the material to be measured, the water does not evaporate and the interior is not dried. The difference in soft X-ray transmittance due to the difference in composition could be photographed and recorded on the dry X-ray dry plate, and the internal structure could be observed. (Embodiment 2) The soft X-ray microscope 1A of the second embodiment shown in FIG. 5 is a vacuum container 3 of the soft X-ray microscope 1 of the first embodiment.
Instead of, a vacuum container 3A having a condensing optical device 3c accommodating the spheroid mirror 9 as a condensing optical system is used between the target accommodating space 3a and the measured material accommodating space 3b. Is. Therefore, the description of the same configuration as that of the first embodiment is omitted.

The vacuum container 3A is a box-shaped body having a substantially rectangular shape, and has a peripheral wall portion 30 and a first partition wall 32a provided with a small hole 31a.
And the second partition wall 32b provided with the small holes 31b, the target housing space 3a formed by dividing the interior surrounded by the peripheral wall portion 30 into three, and the condensing optical device 3c.
And the measured material accommodation space 3b. Condensing optical device 3
c communicates with the target accommodation space 3a through the small hole 31a of the first partition wall 32a, and communicates with the measured material accommodation space 3b through the small hole 31b of the second partition wall 32b.
The size and shape of the small holes 31a and 31b are
It is set to 0.5 mm and 1 mm, respectively. The degree of vacuum can be set to a maximum of 100 Pa in consideration of the flow rate of helium gas.

The condensing optical device 3c houses a spheroidal mirror 9 as a condensing optical system. Spheroid mirror 9
Is a spheroid (the major axis is 653.23 mm, the minor axis is 40.00 mm, and the focus is 32) held by the condensing optical device 3c.
6mm) with a curved surface consisting of a part of 60mm × 82mm
It is a combination of two × 20 mm mirrors. The surface of each mirror is vapor-deposited with gold having a thickness of 5000Å.

When using the soft X-ray microscope 1A of Example 2, first, an aqueous coating film (carbon,
Nitrogen, oxygen, and silicon are used as the composition), and a camera 7 for soft X-ray is prepared, which is loaded with a dry plate for soft X-ray that is brought into close contact with the material to be measured. This camera 7 is fixedly held at a predetermined position in the measured material accommodation space 3b by a holding member 70, and the measured material accommodation space 3b is kept airtight.

Next, the control valve 80 is opened to a predetermined opening degree, and while introducing the helium gas from the supply source 81 into the measured material accommodation space 3b through the gas introduction passage 8, at the same time, the vacuum pump 6 is operated to set the target. The storage space 3a is sucked and the pressure is reduced. At this time, the vacuum degree of the target accommodation space 3a and the measured material accommodation space 3b is adjusted by a Pirani vacuum gauge (not shown) while checking the balance between the suction amount by the vacuum pump 6 and the introduction amount of helium gas by the control valve 80. Controlled.

That is, the degree of vacuum in the material receiving space 3b is determined by the amount of helium gas introduced from the gas introduction passage 8 and
The balance between the small hole 31b of the second partition wall 32b and the amount of helium gas that is sucked out of the small hole 31a of the first partition wall 32a through the light collection optical device 3c and is discharged to the target housing space 3a is controlled by the control valve 80. It is controlled by the size of the opening. The degree of vacuum of the target housing space 3a is a balance between the amount of helium gas introduced through the small holes 31a of the first partition wall 32a and the amount of helium gas sucked out by the vacuum pump 6 and discharged. It is controlled by the magnitude of the suction force.

Thus, the degree of vacuum in the target accommodation space 3a is fixed at 1000 Pa. This degree of vacuum substantially suppresses the absorption and attenuation of the laser light 20, and the target 4
On the other hand, it is a value that can be irradiated with the laser light 20 required to generate the target soft X-ray (see FIG. 10).
In addition, the material-to-be-measured accommodation space 3b is maintained at 1 atm. In this state, the YAG laser device 2 emits the laser light 20 having the same output as that in the first embodiment. The laser light 20 enters through the vacuum window 33 and is condensed on the target 4 by the condenser lens 34. Then, on the target 4,
Laser plasma soft X-rays (hereinafter referred to as soft X-rays) are generated.

This soft X-ray enters the surface of the spheroidal mirror 9 of the condensing optical device 3c at an incident angle of 8 ° from the target accommodation space 3a through the small hole 31a of the first partition wall 32a. Then, 12% of the incident amount of the soft X-ray is reflected from the surface of the spheroidal mirror 9 (wavelength 4.4 nm), and the measured material accommodating space 3b is passed through the small hole 31b of the second partition wall 32b.
Irradiating the soft X-ray camera 7 of
The light is condensed in a region of about 4.5 mm with an intensity of 4.5 times (compared with the case of Example 1).

Then, the difference in the soft X-ray transmittance due to the difference in the composition of the material to be measured loaded into the camera 7 is photographed and recorded on the soft X-ray dry plate in 5000 shots. After that, the camera 7 is taken out from the measured material accommodation space 3b to the outside, and is subjected to observation by developing the photographed dry X-ray dry plate. Therefore, the soft X-ray microscope 1A of Example 2
It was possible to obtain an image of the film formation process of the aqueous coating film.

6 to 8 show images of the film-forming process of the aqueous coating film, which were recorded by photographing with a soft X-ray microscope. The image shown in FIG. 6 is the image that was treated at 80 ° C. for 4 minutes after the coating material was applied. The image shown in Fig. 7 is 1
It was processed for 0 minutes. The image shown in FIG. 8 is obtained by applying the coating material, followed by treatment at 80 ° C. for 10 minutes and then at 150 ° C. for 1 hour.

By observing FIG. 6 to FIG. 8, the water-based coating film showed an increase in the transmittance of soft X-rays as the heat treatment time increased, the recorded image turned black, and the texture changed. You can see the process.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a soft X-ray microscope used in Example 1.

FIG. 2 is an enlarged cross-sectional view showing a vacuum window and a condenser lens formed on a peripheral wall (target accommodation space position) of a vacuum container of the soft X-ray microscope in FIG.

FIG. 3 shows a soft X-ray as a target of the soft X-ray microscope in FIG.
It is a figure which visually recognizes the state where the line was generated and the small hole of the partition wall from the measured material accommodation space side.

FIG. 4 is a diagram showing an image of a termite taken and recorded by a soft X-ray microscope of Example 1.

5 is a diagram showing a schematic configuration of a soft X-ray microscope used in Example 2. FIG.

FIG. 6 is a diagram showing an image of a film-forming process of an aqueous coating film, which is photographed and recorded by a soft X-ray microscope in Example 2.

FIG. 7 is a diagram showing an image of a film-forming process of an aqueous coating film, which is photographed and recorded by a soft X-ray microscope in Example 2.

FIG. 8 is a diagram showing an image of a film-forming process of an aqueous coating film, which is photographed and recorded by a soft X-ray microscope in Example 2.

FIG. 9 is a diagram showing a soft X-ray spectrum from a target (carbon) in an air atmosphere. (Gap between target and soft X-ray detection means: 0.91 m)

FIG. 10 is a diagram showing a soft X-ray spectrum from a target (carbon) in a helium gas atmosphere. (Gap between target and soft X-ray detection means: 0.91 m)

FIG. 11 is a diagram showing a transmission characteristic of soft X-rays in an air atmosphere.

FIG. 12 is a diagram showing transmission characteristics of soft X-rays in a helium gas atmosphere.

[Explanation of symbols]

1.1A: Soft X-ray microscope 2: YAG laser device
20: Laser light 3: Vacuum container 3a: Target accommodation space 3b: Material to be measured accommodation space 3c: Condensing optical device 4: Target 40: Soft X-ray 5: Target rotation device 6: Vacuum pump (rotary pump) 7: Soft X-ray camera 8: Gas introduction passage 9: Spherical mirror

Claims (2)

[Claims] 1. A soft X-ray comprising a laser generating means and a vacuum container having a target for generating soft X-rays and a soft X-ray detecting means for detecting soft X-rays transmitted through a material to be measured. A line microscope, wherein the vacuum container has a target accommodation space for accommodating the target and a measured material accommodation space for accommodating the measured material, wherein the degree of vacuum of the measured material accommodation space is the target accommodation A soft X-ray microscope characterized by having a vacuum degree lower than that of space. 2. The soft X-ray microscope according to claim 1, wherein a condensing optical device for accommodating a condensing optical system is provided between the target accommodating space and the measured material accommodating space.