JPH08327794A - Laser plasma light source - Google Patents

Abstract

PURPOSE: To provide a bright and small laser plasma light source capable of effectively using incident laser energy. CONSTITUTION: A laser plasma light source produces plasma by condensing laser light on a target 25 via a laser incident optical system 22 and generates X-ray from the plasma. An optical system 27 is provided to condense laser light scattered from focus position 26 of the laser light on a target 25 and the generated plasma light again on the focus position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser plasma light source suitable for use as a light source for, for example, an X-ray microscope or an X-ray exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, an X-ray tube or a synchrotron light source has been used as a light source in the X-ray region. However, the X-ray tube can use only specific X-rays, and the synchrotron light source requires a large-scale facility, which is not suitable as a light source on a laboratory scale.

Under these circumstances, a compact white X-ray light source has been developed in recent years. This white X
The linear light source is called a laser plasma light source and is shown in FIG.
As shown in the principle configuration thereof, a target 5 including a metal, which is placed in a vacuum container 4 in which the pulsed laser light 1 is kept at 0.1 Pa or less through a condenser lens 2 and an entrance window 3, is used. 10 ¹² W / cm at its condensing point 6
^The light is focused so as to have an energy of ² or more, whereby the target material is put into a plasma state and white X-rays having a wavelength of 0.5 nm or more are generated.

Here, as the target, a flat target, a tape-shaped target, or, for example, a cylindrical target is used as disclosed in JP-A-5-101797. These targets are moved by the target moving mechanism so that a new surface will come to the laser focus point one after another because the plasmatized material scatters at the laser focus point and leaves a trace. There is. In FIG. 8, by moving the cylindrical target 5 in a spiral shape, new surfaces are successively supplied to the laser focusing points.

Since the laser plasma light source is a white X-ray light source with high brightness, a soft X-ray diffractometer and a photoelectron spectrometer using the same have already been proposed.

However, the conventionally proposed laser plasma light source has the following problems. 1. The incident laser energy is not efficiently absorbed by the target and a considerable part is scattered on the target surface, so that the conversion efficiency into soft X-rays is low and the light source is dark. 2. The plasmatized substance scatters, and the scattered target substance adheres to the X-ray optical system, the detector, etc., resulting in attenuation of X-rays and deterioration of detection efficiency. In particular, as shown in FIG. 9, a Schwarzschild type optical element 13 in which a concave mirror 11 and a convex mirror 12 in which multilayer films are laminated respectively are combined.
Alternatively, as shown in FIG. 10, in the Fresnel zone plate optical element 14 that utilizes diffraction, the surface of the optical element and the scattering direction of the target material are substantially perpendicular to each other, so that the X-ray transmittance due to the adhesion of the target material The decrease is significant. Further, as shown in FIG. 11, an oblique-incidence total reflection type optical element 15 in which X-rays are incident on the reflecting surface at a large angle (in the case of FIG. 11, it is formed by connecting a rotating hyperboloid and a rotating ellipsoid). In the Wolter mirror), the decrease in the X-ray transmittance due to the adhesion of the target material is small, but the scattered target material is repelled by the mirror surface and affects the optical system in the subsequent stage.

As a method for solving such a problem, the following method has been conventionally proposed. (1) As a method of realizing a bright light source, (11) Enhancing the brightness by confining plasma with a strong magnetic field. (12) Proceedings of the 55th SPSJ Annual Meeting, 2nd
Incident lasers are decomposed into pulse trains to increase brightness, as disclosed in Volume 21a-ZN-1. (2) As a method of preventing the scattering and adhesion of the target material, (21) as disclosed in JP-A-56-116622, the plasma material is directed to the outside of the optical system by using a high frequency high voltage. (22) Japanese Patent Application Laid-Open No. 58-40757, Proceedings of 55th Academic Meeting of Applied Physics, 2nd Volume, 21a-ZN
As disclosed in -2, the scattering of the target substance is hindered by gas or the like. (23) As disclosed in JP-A-57-130350, a capture film of Be, Si, or the like inhibits scattering of the target material. (24) The shield plate with holes is rotated to shield only the target material that is scattered after the plasma light.

[0008]

However, in the method of (11) above, since a mechanism for generating a strong magnetic field is required, there is a problem that the light source is inevitably large in size. The method 12) has a problem in that the apparatus becomes large in size because a space is required to decompose the incident laser into a pulse train.

Further, in the conventional laser plasma light source, when the laser light is focused on the target, there is laser light scattered without participating in plasma generation. Further, of the generated plasma light, the light incident on the X-ray optical system is only a part of the plasma light diverging in all directions, and most of the rest is wasted. Energy is not considered in (11) and (12) above.

The above method (21) has a problem that the apparatus becomes large in size because a high frequency power source is required, and the method (22) causes gas or the like to enter the vacuum container. In addition to the need for a device for introducing, the exhaust volume of the vacuum pump for exhausting the introduced gas increases, and further, when using a detector that requires a high voltage such as a microchannel plate, discharge In order to prevent this, a differential pumping mechanism for maintaining a high vacuum in the vicinity of the detector is required, which also causes a problem that the device becomes large.

Further, in the above method (23), since the target material attached to the trapping film absorbs the soft X-rays, the transmittance of the soft X-rays decreases with time. Therefore, it is necessary to frequently replace the capture film, which causes a problem that maintenance is troublesome.

Further, in the above method (24),
Since the speed of the scattered target material has a speed of several km / s to several tens of km / s, there is a problem that the rotational speed of the disk becomes extremely large. For example, the velocity of the target material is 2 km / s to 50 km / s, the diameter of the optical path to be shielded is 10 mm, the distance from the light source to the shield plate is 500 mm, the hole diameter of the shield plate is 10 mm, the center of the hole to the center of the disc. At a distance of up to 50 mm, a rotation speed of 3172 rpm or more is required to shield the target particles that fly the fastest, and 3873 rotations per second to shield the target particles that fly the slowest. The following speeds are required. Therefore, in order to shield all the target particles, a rotation speed of 3172 rotations per second or more and 3873 rotations or less per second is required. Therefore, some kind of cooling means is required to rotate the vacuum motor.

Further, the method (24) has a problem that it is difficult to downsize the apparatus. For example, if the distance from the center of the hole of the shield plate to the center of the disc is 30 mm in order to miniaturize the device, the rotation speed of 5255 rpm or more is required to shield the target particles that fly the fastest. In order to shield even the target particles that are flying the slowest, a rotation speed of 3789 rpm or less is required per second. Therefore, in order to shield all the target particles, a rotation speed of 5255 rotations / second or more and 3789 rotations / second or less is required, which is an unrealizable system.

A first object of the present invention is to provide a laser plasma light source which is appropriately configured so that incident laser energy can be effectively used, and therefore can be made bright and can be made compact.

Further, the second object of the present invention is to effectively shield the scattered target material with a simple and compact mechanism, and therefore, in the case of using a laser plasma light source.
An object of the present invention is to provide a laser plasma light source appropriately configured so as to effectively prevent undesired adhesion of a target material to a linear optical system.

[0016]

In order to achieve the first object, the first invention is to collect a laser beam on a target through a laser incident optical system to generate a plasma, and to generate a plasma from the plasma. In a laser plasma light source adapted to generate X-rays, an optical system for converging the laser light scattered from the condensing position of the laser light on the target and the generated plasma light to the converging position again is provided. It is characterized by.

Further, in order to achieve the above second object,
A second aspect of the invention is a laser plasma light source configured to generate a plasma by focusing laser light on a target via a laser incident optical system, and to focus the plasma in a laser plasma light source configured to generate X-rays from the plasma. An oblique-incidence reflection-type condenser lens and a shielding member that is provided in the vicinity of the light-condensing position of the oblique-incidence reflection-type condenser lens and shields scattered target material and a shielding unit having a driving mechanism therefor are provided. It is a thing.

[0018]

In the first aspect of the invention, the laser light scattered from the condensing position of the laser light on the target and the generated plasma light are condensed again at the condensing position by the optical system. Thus, when the energy of the scattered laser light is reinjected into the plasma, the temperature of the plasma rises and brighter light is generated. Further, the generated plasma light contains light having a shorter wavelength than the laser light, and the laser plasma light source is more efficient as the wavelength of the light exciting the plasma is shorter. When the plasma light is injected into the plasma again, a brighter plasma light will be produced. Therefore, it is possible to obtain a bright light source that effectively utilizes the incident laser energy with a simple and compact structure in which an optical system is added.

Further, in the second invention, the plasma light generated from the target is condensed by the oblique incidence reflection type condenser lens which is less affected by the adhesion of the target material, and the scattered target material is obliquely incident and reflected. It will be shielded by a shielding member having a drive member and a shielding member arranged in the vicinity of the condensing position of the mold condenser lens. Therefore, the cross-sectional area of the optical path that shields the target material is reduced, so that the shielding member can be downsized and the load on the drive mechanism can be reduced accordingly.

Further, by providing the shielding means after the grazing incidence reflection type condenser lens, the optical path length from the condensing point of the target to the shielding means can be made large, so that the difference in the arrival time between the plasma light and the scattered material is large. Become. Therefore, since the moving speed of the shielding member can be reduced, the shielding means does not require an additional mechanism such as a cooling device together with the miniaturization of the shielding member and the reduction of the load on the drive mechanism. It is possible to make the device simple and small, and it is possible to downsize the entire device.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention. This laser plasma light source has a basic structure similar to that of the principle diagram shown in FIG. 8, and is, for example, Nd-YA.
Double harmonic of G pulse laser (wavelength 532nm) 21
Through a condenser lens 22 and an entrance window 23, and is focused on a target 25 arranged in a vacuum container 24, whereby plasma is generated on the focusing point 26. In addition, in FIG. 1, a flat plate made of copper is used as the target 25, and a new surface is formed at the condensing point 2 each time the laser is irradiated.
The target 25 is two-dimensionally moved so as to be located on the position 6.

In this embodiment, a spherical mirror 2 made of oxygen-free copper having a radius of 50 mm with the focusing point 26 substantially at the center on the focusing point 26 side of the laser beam and above the target 25.
7 is arranged, and the spherical mirror 27 is provided with a hole 28 for laser incidence.
And a hole 29 for X-ray emission is formed, the laser light 21 is guided to the target 25 through the hole 28, and the plasma light generated at the converging point 26 thereof is passed through the hole 29 to the X-ray optical system 30.
To lead.

In FIG. 1, when the laser light 21 is focused on the focusing point 26 on the target 25, plasma light is generated. At this time, the laser light scattered without contributing to plasma generation and the generated plasma light are generated. , Will be spread around the condensing point 26. However, among the spread light, the spherical mirror 2
The light reflected by the metal 7 is injected again into the plasma generated at the converging point 26, and the generated and scattered light spreads around the converging point 26 and is reflected by the spherical mirror 27 to be condensed. We will return to point 26. This process is repeated until the target material diffuses and the density decreases, and the life of the plasma is exhausted.

According to this embodiment, since the energy of scattered laser light is reflected by the spherical mirror 27 and injected again into the plasma with a simple and compact structure in which the spherical mirror 27 is added, the temperature of the plasma rises. It is possible to generate brighter light. Further, the scattered plasma light including light having a shorter wavelength than the laser light is reflected by the spherical mirror 27 and injected into the plasma again, so that the plasma can be efficiently excited and a brighter plasma light is generated. You can

In FIG. 1, the spherical mirror 27 is made of copper, which is the same material as the target 25, in order to prevent the reflectance from changing even if the target material adheres to the spherical mirror 27. Target material thickness is 27
Since the reflectance will no longer change when it adheres to a thickness of 00 nm or more, the target 25 and the spherical mirror 27 are not limited to the same material, and may be arbitrarily selected from substances that cause metal reflection such as metals such as iron, niobium, and nichrome, and alloys. You can
Further, the shape of the target is not limited to a flat surface, and the same effect can be obtained when the target has a cylindrical shape, a tape shape, a linear shape, or a liquid shape.

Further, in FIG. 1, the center of the spherical mirror 27 and the focal point 26 are substantially aligned with each other. However, since the center of the plasma is located slightly away from the surface of the target 25, the spherical mirror 27 is located. Strictly speaking, it is desirable that the center of is in the center of the generated plasma. However, the diameter of the generated plasma is around 100 μm, and if the center of the spherical mirror 27 and the converging point 26 are substantially aligned, the light is effectively condensed in the plasma generation region. The center and the center of the plasma do not have to be exactly the same.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, instead of the spherical mirror of the first embodiment,
A spheroidal mirror 31 is used so that the laser light and the plasma light once diverged can be condensed again. The mirror 31 has a laser beam 33 whose one end of the spheroid is focused on the target 32.
It is arranged so as to be located at the condensing point 34 of.

In this way, the laser light 33 is condensed on the target 32 through the condenser lens 37 and the hole 38 formed in the mirror 31, and the plasma light generated at the condensing point 34 is formed on the mirror 31. The laser light and plasma light diverged in a direction different from the direction of the X-ray optical system 36 are reflected by the mirror 31 while being guided to the X-ray optical system 36 through the hole 35, and the other focus 34 'of the spheroid is formed. After that, the light is reflected again by the mirror 31 and condensed on the condensing point 34.
Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained.

In the first and second embodiments, the light source is brightened by a principle different from the conventional methods (11) and (12). By using the method (11) and the method (12) together, it is possible to realize a light source with higher brightness.

FIG. 3 shows a third embodiment of the present invention. This embodiment is applied to an X-ray laser using a laser plasma, in which a tape-shaped target 82 made of aluminum is placed in a vacuum container 81, and a cylindrical condenser lens 83, 84 is placed on the target 82.
Then, through the entrance windows 85 and 86, for example, the laser beams 87 and 88 of the second harmonic (wavelength 532 nm) of the Nd-YAG pulse laser are linearly condensed, and their condensed lines 89 are formed.
Plasma is generated above, and thereby X-ray laser light is generated in the direction of the focusing line. It should be noted that the target 82 is moved within the target plane so that a new surface is located on the converging line 89 each time the laser is irradiated.

In the vacuum container 81, the target 8
A cylindrical mirror 90 made of aluminum and having a condensing line 89 on the axis of symmetry and having a radius of 100 mm, for example, is arranged so as to surround 2. The cylindrical mirror 90 has laser beams 87, 88
Holes 91 and 92 for incidence of are formed.

In this structure, the laser light 87, 88
The cylindrical condenser lenses 83, 84 and the entrance window 8
When the light is focused on the target 82 linearly through the holes 5, 86 and the holes 91, 92, plasma is generated on the focused line 89. At this time, the scattered laser light and the generated plasma light that do not contribute to plasma generation spread around the converging line 89, but the light that is metal-reflected by the cylindrical mirror 90 among the expanded light is the condensing line again. The light injected into the plasma generated in 89 and further generated and scattered spreads around the condensing line 89, is reflected by the cylindrical mirror 90, and returns to the condensing line 89. This process is repeated until the target material diffuses and the density decreases, and the life of the plasma is exhausted.

As described above, according to this embodiment, the energy of the scattered laser light is injected into the plasma again, so that the temperature of the plasma rises and the intensity of the generated X-ray laser light can be increased. In addition, the generated plasma light includes light having a shorter wavelength than the incident laser lights 87 and 88, and the laser plasma has higher efficiency as the wavelength of light for exciting the plasma is shorter. By being injected into the plasma again, the intensity of the X-ray laser can be further increased. Therefore, it is possible to obtain an X-ray laser having high intensity, which effectively utilizes the incident laser energy.

FIG. 4 shows a fourth embodiment of the present invention. This embodiment shows an image-forming laser soft X-ray microscope using a laser plasma light source, in which a laser plasma light source 42 arranged in a vacuum container 41 and a spheroidal oblique reflection type condenser made of oxygen-free copper. 43, shielding means 44, sample 45, Schwarzschild type objective lens 4
6 and a microchannel plate 47. A laser plasma light source 42 having the same configuration as that shown in FIG. 1 is used, and in this laser plasma light source 42, a laser beam 50 condensed through a condenser lens 48 and an entrance window 49 is used, so Soft X as explained
Generate a line.

Soft X generated from the laser plasma light source 42
The lines are the grazing incidence reflection type condenser 43 and the shielding means 44.
The light is focused on the sample 45 via the, and the soft X-rays transmitted and diffracted by the sample 45 are imaged on the microchannel plate 47 via the Schwarzschild type objective lens 46.
In this embodiment, the optical path length from the light emitting point of the laser plasma light source 42 to the sample 45 is 0.5 m. The flight speed of the target material generated and scattered from the laser plasma light source 42 is 2 km / s to 50 km.
/ S.

As shown in FIGS. 5A, 5B and 5C, the shielding means 44 includes a rotary plate 52 which constitutes the fixed plate 51 and the shielding member, and a vacuum motor (not shown) which constitutes a drive mechanism for the rotary plate 52. ) And. Openings 53 and 54 having a diameter of about 0.1 mm are formed in the fixed plate 51 and the rotary plate 52, respectively. In this embodiment, the rotary plate 5
The distance (radius) from the center of 2 to the center of the opening 54 is 3
It is set to 0 mm. A vacuum motor (not shown) is directly connected to the center of the rotary plate 52 to rotate the rotary plate 52 in synchronism with the oscillation of the laser incident on the laser plasma light source 42.

In this embodiment, the target material that reaches the light shielding means 44 fastest is 1 × after plasma emission.
It will be 10 ^-5 seconds. Therefore, as shown in FIG. 5A, in the rotary plate 52, the opening portion 54 has the opening portion 53 of the fixed plate 51.
As shown in FIG. 5B, the time until the opening 53 of the fixing plate 51 is completely covered is rotated so as to be shorter than the above time. That is, the rotary plate 52,
It is rotated at 53 revolutions per second or more in synchronization with the oscillation of the incident laser. In this way, the opening 54 of the rotary plate 52
However, the time until the next overlap with the opening 53 of the fixing plate 51 is about 1/53 seconds, so that it is possible to shield all the target substances of about 26 m / s or more.

As described above, according to this embodiment, since the same laser plasma light source 42 as that shown in FIG. 1 is used, the light source itself can be made bright and compact. Further, by rotating the rotary plate 52 at a low rotation speed that can be realized by a normal vacuum motor, the target material scattered from the laser plasma light source 42 can be effectively shielded, so that a complicated mechanism is not required.
The Schwarzschild type objective lens 46 in the subsequent stage can be effectively protected from the target substance, and the entire structure can be made compact.

FIG. 6 shows a fifth embodiment of the present invention. This embodiment shows a soft X-ray optical system capable of selecting a soft X-ray having a desired wavelength, and has a laser plasma light source 61, a condenser 62, a shielding means 63 and an oblique incidence type spectroscope 64. The laser plasma light source 61 is
In this laser plasma light source 61, a laser beam 66 condensed through a condenser lens 65 is used to generate soft X-rays as described in FIG. 1, using a structure similar to that shown in FIG. . The optical path through which the soft X-rays pass and the optical system are arranged in a vacuum container (not shown) in order to avoid absorption of the soft X-rays by air.

Soft X generated from laser plasma light source 61
The line is condensed by the condenser 62 and is oblique incidence type spectroscope 6
4. The capacitor 62 is, in this embodiment,
It is composed of a grazing incidence reflection type mirror in which a spheroidal aluminum substrate is coated with gold.

The grazing incidence type spectroscope 64 comprises an entrance slit 67 having a width of 10 μm and a platinum-coated lattice spacing 1200.
A book / mm concave diffraction grating 68 and a 10 μm wide exit slit 69 are provided, and these are arranged so as to be located on the Rowland circle 70. Here, the entrance slit 67 is fixedly arranged at the condensing position by the condenser 62, the concave diffraction grating 68 is fixedly arranged so that the center of the concave surface is located on the Rowland circle 70, and the exit slit 69 is It is movably arranged on the Roland circle 70.

In this way, the soft X-rays that have passed through the entrance slit 67 are separated by the concave diffraction grating 68 and condensed for each wavelength on the Rowland circle 70, and the soft X-rays of the desired wavelength are converted to Roland. By moving the exit slit 69 on the circle 70, it is selected and taken out. In this embodiment, the optical path length from the light emitting point of the laser plasma light source 61 to the entrance slit 67 is 1.0 m. The flight speed of the target material generated and scattered from the laser plasma light source 61 is 2 km / s to 50 km.
/ S.

The shielding means 63 is arranged on the incident side of the oblique incidence type spectroscope 64 and in the vicinity of the condensing position of the condenser 62. As shown in FIG. 7, the shielding means 63 includes a leaf spring 72 supported by a piezoelectric element (PZT) 71 and the leaf spring 7.
2 has a light-shielding plate 73 attached to the light-shielding plate 73, and the piezoelectric element 71 causes the light-shielding plate 73 to pass through the leaf spring 72. As described above, it is configured to vibrate in a sine wave shape. In this embodiment, the displacement of the piezoelectric element 71 is magnified ten times by the leaf spring 72. The piezoelectric element 71 is driven in synchronization with the light emission of the laser so that the laser emits immediately before the light blocking plate 73 starts to cover the entrance slit 67.

In this embodiment, the target material that reaches the shielding means 63 fastest is 2 × after plasma emission.
10 ^-5 seconds, the target material that arrives the slowest is
It becomes 50 × 10 ⁻⁵ seconds after plasma emission. The plasma light is generated immediately before the light blocking plate 73 starts to cover the entrance slit 67. Therefore, the shield plate 73 is completely shielded by the piezoelectric element 71 within 2 × 10 ⁻⁵ seconds after the plasma emission so that the entrance slit 67 is opened again after 50 × 10 ⁻⁵ seconds. The plate spring 72 vibrates in a sine wave shape. Therefore, in this example,
The piezoelectric element 71 is vibrated at an amplitude of ± 10 μm at 800 Hz, the amplitude is amplified ten times by the leaf spring 72, and the shield plate 73 is vibrated at an amplitude of ± 100 μm at 800 Hz. By doing so, the incident slit 67 is completely shielded by the shielding plate 73 within 2 × 10 ⁻⁵ seconds after the plasma light is generated, so that the target material does not reach the oblique incidence spectroscope 64. Absent.

As described above, according to this embodiment, since the same laser plasma light source 62 as that shown in FIG. 1 is used, the light source itself can be made bright and compact. Further, since the target material scattered from the laser plasma light source 61 can be effectively shielded by vibrating the shield plate 73, the latter oblique incidence spectroscope 64 can be effectively shielded from the target material without requiring a complicated mechanism. Can be protected, and the whole can be made compact.

Appendix 1. In a laser plasma light source configured to generate a plasma by condensing a laser beam on a target through a laser incident optical system and scatter from a condensing position of the laser beam on the target. A laser plasma light source, comprising an optical system for condensing the generated laser light and the generated plasma light to the condensing position again. 2. 2. The laser plasma light source according to appendix 1, wherein the shape of the condensing position is configured in a dot shape. 3. 2. The laser plasma light source according to appendix 1, wherein the light collecting position is configured to have a linear shape. 4. 4. The laser plasma light source according to appendices 1, 2 or 3, wherein the optical system is a reflection optical system. 5. 5. The laser plasma light source according to appendix 4, wherein the reflection optical system has a spherical mirror. 6. 5. The laser plasma light source according to appendix 4, wherein the reflective optical system has a spheroidal mirror. 7. 5. The laser plasma light source according to appendix 4, wherein the reflective optical system has a cylindrical mirror. 8. An X-ray laser in which laser light is linearly focused on a target via a laser incident optical system to generate plasma, and the laser is generated from the plasma. An X-ray laser provided with a cylindrical mirror for condensing the laser light scattered from and the generated plasma light again to the condensing position. 9. A laser plasma light source configured to collect a laser beam on a target through a laser incident optical system to generate a plasma and generate an X-ray from the plasma. A laser plasma light source, comprising: a lens; and a shielding member that is provided in the vicinity of a condensing position of the condenser lens and shields scattered target material, and a shielding unit having a driving mechanism thereof. 10. 10. The laser plasma light source according to appendix 9, wherein the drive mechanism is configured to rotate the shielding member by a rotary drive source. 11. 11. The laser plasma light source according to appendix 10, wherein the rotation drive source is constituted by a motor. 12. Note 9 is characterized in that the drive mechanism is configured to reciprocally drive the shielding member by a reciprocating drive source.
The laser plasma light source described. 13. 13. The laser plasma light source according to appendix 12, wherein the reciprocating drive source is composed of a piezoelectric element. 14. 10. The laser plasma light source according to appendix 9, wherein the condenser lens is a spheroidal mirror. 15. 10. The laser plasma light source according to note 9, wherein the condenser lens is a rotating parabolic mirror. 16. 10. The laser plasma light source according to appendix 9, wherein the condenser lens is a Walter mirror.

[0047]

As described above, according to the first aspect of the present invention, the optical system for converging the laser light scattered from the condensing position of the laser light on the target and the generated plasma light to the converging position again is provided. Since the incident laser energy can be effectively used with a simple and compact structure, a bright laser plasma light source can be obtained.

According to the second invention, the scattered target material can be effectively shielded by a simple and small mechanism, so that X in the case where the laser plasma light source is used.
It is possible to effectively prevent unwanted adhesion of the target material to the linear optical system and obtain a clean laser plasma light source.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is likewise a diagram showing a second embodiment.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is also a diagram showing a fourth embodiment.

FIG. 5 is a diagram for explaining the configuration of an example of the shielding unit shown in FIG.

FIG. 6 is a diagram showing a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of an example of a shielding unit shown in FIG.

FIG. 8 is a diagram showing a principle configuration of a laser plasma light source.

FIG. 9 is a diagram showing a Schwarzschild type optical element.

FIG. 10 is a diagram showing a Fresnel zone plate optical element.

FIG. 11 is a diagram showing an oblique-incidence total reflection type optical element.

[Explanation of symbols]

 21 laser light 22 condensing lens 23 entrance window 24 vacuum container 25 target 26 condensing point 27 spherical mirrors 28, 29 hole 30 X-ray optical system 31 spheroidal mirror 32 target 33 laser light 34 condensing point 34 'focus 35 , 38 holes 36 X-ray optical system 37 Condensing lens 41 Vacuum container 42 Laser plasma light source 43 Oblique incidence reflection type condenser 44 Shielding means 45 Sample 46 Schwarzschild type objective lens 47 Micro channel plate 48 Condensing lens 49 Incident window 50 Laser light 51 Fixed Plate 52 Rotating Plate 53, 54 Opening 61 Laser Plasma Light Source 62 Condenser 63 Shielding Device 64 Oblique Incident Spectrometer 65 Condenser Lens 66 Laser Light 67 Incident Slit 68 Concave Diffraction Grating 69 Emission Slit 70 Roland Circle 71 Piezoelectric Element ( PZT 72 the leaf spring 73 the light shielding plate 81 vacuum chamber 82 target 83, 84 cylindrical condenser lens 85 and 86 incident window 87, 88 laser light 89 Vol beam 90 cylindrical surface mirrors 91 and 92 holes

Claims (2)

[Claims] 1. A laser plasma light source configured to generate a plasma by condensing a laser beam on a target through a laser incidence optical system, and to generate an X-ray from the plasma. A laser plasma light source comprising an optical system for condensing laser light scattered from a condensing position and generated plasma light to the condensing position again. 2. A laser plasma light source configured to generate a plasma by converging a laser beam on a target through a laser incident optical system and generate X-rays from the plasma. A laser provided with an incident reflection type condenser lens and a shielding member which is installed in the vicinity of a condensing position by the oblique incidence reflection type condenser lens and shields scattered target material and a shielding means having a driving mechanism thereof. Plasma light source.