JPH10319196A - Device for adjusting optical axis of x rays - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to identify detailed intensity profiles of X-ray beams and positions of beam paths with a precision of 1 mm or less. SOLUTION: By varying the intensity of an X-ray beam 1 of an X-ray domain while shielding it little by little against soft X rays with board 2 with a sharp knife edge and a wire, the distribution of beam intensity is measured, the central position of the beam is accurately measured and the position of the X-ray beam 1 is marked with the same accuracy in a space with the position of the edge. This makes it possible to measure an actual path of an X-ray beam accurately and easily and adjust each optical component of a beam line device quickly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam line apparatus for an X-ray beam in the range from soft X-rays to X-rays, and relates to a technique for adjusting the optical axis of an optical element constituting a beam line.

[0002]

2. Description of the Related Art Emission light from an electron or positron storage ring and light in a soft X-ray to X-ray region (hereinafter abbreviated as X-ray) from a laser plasma X-ray source are used to efficiently place X-rays on a sample. Beamline devices installed to guide the lines use many optical components, such as reflectors, diffraction grating spectrographs, double crystal spectrometers, slits, pinholes, and filters of various shapes. These optical components must be placed in a designed arrangement in order to efficiently guide X-rays with physical properties suitable for measurement. For the installation of optical components, the spatial distribution of the intensity distribution of the X-rays from the light source or the X-rays that have passed through one or more optical components actually pass through It is essential to know what you have.

[0003] Since X-rays cannot be visually observed, a method different from ordinary optical experiments using visible light is required. In addition, since the emitted light from the bending electromagnet has a visible light component, it is possible to perform rough optical axis alignment using this visible light on a soft X-ray beam line that is vacuum-connected to the storage ring. However, it cannot be measured because the true X-ray intensity distribution is different from the visible light intensity distribution. In the case of a hard X-ray beam line where a Be filter or the like is installed to block visible light, or a laser plasma X-ray source where a filter is installed to prevent scattered particles from entering the analysis chamber, the visible light from the light source is used. No ingredients are available. For this reason, it is necessary to measure the path through which the X-rays pass in order to align the optical axis of the beamline optical component. Also, in a beam line that can use the emitted light visible light component,
Accurately grasping the path of a line is important for optimizing the installation of optical components, particularly for installing a spectroscope or the like. Up to now, optical component alignment for using X-rays has been performed by installing a fluorescent plate or the like on an optical path and visualizing the X-rays. Alternatively, a surveying instrument such as an automatic level is used to install a reflector or the like, relying on the approximate position of the X-ray path found by this method and the optical path in the design.

[0004]

In the case where the X-ray source has high brightness or the beam shape is reduced to a sub-mm size or less by shaping the beam shape with a slit or the like, the method of visualizing the X-ray by the fluorescent plate is not used. It was difficult to know the detailed intensity profile and the position of the beam path with an accuracy of 1 mm or less. From the viewpoint of radiation protection, observation of the fluorescent screen during X-ray generation is performed through a camera or the like, and it is difficult to determine the peak position of the intensity distribution in more detail. Further, the designed beam path may not coincide with the actual beam path due to the manufacturing accuracy of the optical element or the like, and it takes enormous effort and time to perform the optimal installation.

[0005]

SUMMARY OF THE INVENTION In the range from soft X-rays to X-rays,
X-ray beam intensity distribution with better accuracy than mm by changing the X-ray beam intensity while gradually shielding the X-ray beam with an X-ray shield such as a plate or wire with a sharp knife edge After measuring the position of the highest intensity, that is, the center position of the beam with an accuracy of better than mm, the position of the X-ray beam is marked in space with the position of the edge.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

<Example 1> An example of an apparatus for measuring an intensity profile of an X-ray beam in the range from soft X-rays to X-rays (hereinafter abbreviated as X-ray beam), which is a main component of the present invention, is an example of measuring a vertical profile of an X-ray beam. It will be described as. FIG. 1 is a diagram showing a state in which an X-ray beam 1 generated from a light source passes from left to right in the figure as viewed from a horizontal direction. Although the X-ray beam actually passes through the vacuum pipe, it is omitted in this drawing. Shielding materials for radiation protection are also omitted. In order to measure the vertical intensity profile of the X-ray beam, for example, an edge plate 2 having a sharp knife edge is arranged so as to block the X-ray beam from above or below the X-ray beam along the vertical axis. Move. The edge plate 2 is made of a conductive material (for example, SUS304 or aluminum), and is installed on a support member 4 via an insulator 3. On the light source side of the edge plate 2, a film 5 of a material having a large cross-sectional area of photoionization with respect to X-rays such as Au, Pt, Ag, etc. is formed so that photoelectron generation by irradiation of a radiated light beam occurs more effectively. May be formed by a method such as vapor deposition. In a preferred embodiment, Au may be formed to a thickness of about 1000 to 2000 mm by a vacuum evaporation method. When the edge plate 2 blocks the X-ray beam 1, photoelectrons 6 are generated. Since the edge plate 2 is attached insulated, a current flows through the signal line 7, and this current is measured by the ammeter 8.

When the current flowing through the edge plate 2 is measured while moving the edge plate 2 in the direction of the arrow in the figure, and the amount of movement of the edge plate 2 and the measured value of the ammeter 8 are plotted, a curve as shown in FIG. can get. When the knife edge of the edge plate 2 is not initially exposed to the X-ray beam 1, the current amount hardly changes except for noise components. This is the area shaded with area 1 in FIG. When the knife edge of the edge plate 2 begins to block the X-ray beam 1, the amount of current increases according to the amount and intensity of the blockage of the X-ray beam 1. This is shown in FIG.
This is an area shaded with the area 2. When the edge plate 2 completely blocks the X-ray beam 1, a current corresponding to the total intensity of the X-ray beam 1 continues to flow regardless of the amount of movement of the edge plate 2. This is the area shaded with the area 3 in FIG.

[0008] This curve is obtained by installing a motor-driven straight introducer 9 as a moving mechanism of the edge plate 2, controlling a controller 11 for controlling a driver 10 of the motor-directed straight introducer 9 by a computer 12, and controlling the current. The total 8 can also be obtained very simply and quickly by being controlled by the computer 12.
In addition, since there is no hindrance to remote control, radiation protection,
Even when a person cannot enter, a detailed intensity profile of the X-ray beam 1 can be obtained. When this curve is numerically differentiated by the computer 12 with the movement amount of the edge plate 2, the intensity profile of the X-ray beam 1 shown in FIG. 3 can be obtained. The peak position of this intensity profile is the center position of this X-ray beam 1 path.
The accuracy of the intensity profile obtained in this way is determined by the accuracy of the movement amount of the edge plate movement, and can be determined with a micron-order accuracy by moving the edge plate using a stepping motor or the like. Furthermore, by using the piezo element in combination, the accuracy of the order of nanometer is not impossible.

If data on the movement amount of the edge plate 2 is stored in the computer 12, the position through which the X-ray beam 1 passes can be known any number of times later. If the knife edge of the edge plate 2 is moved again to the center position of the X-ray beam 1 stored in the computer 12, the position of the X-ray beam 1 can be marked in space.
The data of the position measurement of the X-ray beam 1 can be easily used for adjustment using visible light, such as introduction of a laser beam or observation using an automatic level. The knife edge system for measuring the position and intensity profile of the X-ray beam 1 and the knife edge system for beam position marking may be configured as independent knife edge systems.

According to the present invention, the path of the X-ray beam can be measured accurately and easily, and the adjustment of each optical component of the beam line device can be performed quickly and accurately.

<Embodiment 2> This embodiment is an example using a wire instead of an edge plate as an X-ray shield. FIG. 4 is a view similar to FIG. In order to measure the vertical intensity profile of the X-ray beam, the wire 13 is moved from above or below the X-ray beam along the vertical axis so as to block the X-ray beam 1. The wire 13 is made of a conductive wire and is installed on a support member 15 via an insulator 14. Also, the wires 13 are made of Au, so that photoelectrons are more effectively generated by irradiation of the X-ray beam.
It is preferable to use a material such as Pt or Ag, which has a large cross section for photoionization with respect to light in the soft X-ray to X-ray region. Alternatively, a coating of these materials may be formed on the wire 13.
When the wire 13 blocks the X-ray beam 1, photoelectrons 5 are generated. Since the wire 13 is insulated, a current flows through the signal line 7, and this current is measured by the ammeter 8. Other configurations are the same as in the first embodiment.

First, when the diameter of the wire 13 is sufficiently larger than the width of the X-ray beam, the beam position and the profile can be obtained by the same operation as in the first embodiment. When the diameter of the wire 13 is sufficiently smaller than the width of the X-ray beam 1, the current flowing through the wire 13 is measured while the wire 13 is advanced in the direction of the arrow in FIG.
By plotting the movement amount of No. 3 and the measured value of the ammeter 7, the same curve as the curve of FIG. 3 can be directly obtained. In that case, the position accuracy of the intensity profile is determined by the thickness of the wire 13.

According to the present invention, the path of an X-ray beam can be measured accurately and easily without taking the differentiation or difference of a signal, and the adjustment of each optical component of the beam line device can be performed quickly and accurately. it can.

<Embodiment 3> In Embodiment 1, the X-ray beam 1
Vertical position and intensity distribution of
The horizontal position and intensity distribution could not be measured. The embodiment shown in FIG. 5 uses the knife edge system of the first embodiment in two axes, and
This is a configuration for obtaining the position and intensity profile in both the vertical and horizontal directions. When the direction in which the X-ray beam 1 travels is the y-axis, the vertical direction is the z-axis, and the horizontal direction is the x-axis, the edge plate 2 of the first embodiment is set so as to move along the x-axis and the z-axis. . Other current measurement systems and edge plate drive systems are described in Example 1.
It is omitted because it is the same as. When the wire 13 is used in place of the edge plate 2, the structure can be exactly the same.

According to this embodiment, the position and intensity profile of the X-ray beam in both the vertical and horizontal directions can be measured.

<Embodiment 4> In Embodiment 3, two X-ray shields such as an edge plate and a wire are used and introduced from two directions. In this case, two introduction ports to the vacuum chamber are required. However, when sharing with other vacuum components, such as a vacuum gauge port, is required, it is necessary to occupy as few ports as possible. Therefore, as shown in FIG. 6 (a), if an edge plate in which both vertical and horizontal edges 17 are formed on one plate 16 is used, it is introduced from above vertically through one vacuum port, By moving two-dimensionally in the x-axis and z-axis directions in the figure, the position and intensity distribution of the X-ray beam can be measured both vertically and horizontally.

In the case of a wire, the same effect as in the case of the edge plate 16 can be obtained by using a wire in which two wires are stretched perpendicular to the frame 18 as shown in FIG.

According to this embodiment, the position and intensity distribution of the X-ray beam can be measured in both the vertical and horizontal directions by using only one vacuum port.

<Embodiment 5> When light having a wide range of energy, such as light emitted from a bending electromagnet, is generated, in measuring the position and intensity distribution of an X-ray beam, a beam due to the mixing of low energy light is used. It is necessary to avoid misalignment and broadening of the intensity profile.
In particular, in the case of a soft X-ray beam line device in the case of a synchrotron radiation light source, there is often nothing that blocks light on the low energy side from the light source, and shielding such low energy side light is important. is there. In the embodiment shown in FIG. 7, the filter 19 is inserted on the light source side of the X-ray optical axis adjusting device, and the purpose is to measure the beam position and the intensity profile only with the high energy component. As the filter 19,
A foil of Be, Al, Ti, Ni, BN, Fe, Cu, C, Si, or the like can be used. The filter 19 is attached to a support member 20 installed in the straight introduction device, and can be manually or automatically inserted into and removed from the X-ray beam path as needed.

According to this embodiment, mixing of low-energy light can be prevented, and the X-ray beam position and intensity profile of only necessary soft X-ray components can be measured. In this figure, X
Only the case of the knife edge described in Example 1 as a line beam profile measuring device is shown. The same effect can be obtained with the configuration described in the second embodiment using a wire. <Embodiment 6> The embodiments described so far mainly relate to an apparatus for measuring an X-ray beam position and an intensity profile. In the present embodiment, an apparatus for adjusting a beamline optical component such as a reflecting mirror using the position of the X-ray beam determined as described above will be described. FIG. 8 shows a schematic diagram of this system.

The knife edge systems 21 and 22 as shown in the first embodiment are installed at two places on the optical path 23 of the X-ray beam. The X-ray intensity profile is measured at each position by both knife edge systems, and the X-ray beam path is determined from the position of the knife edge where the maximum differential current value (see FIG. 3) is obtained, for example. Next, on the light source side of the knife edge system 21, a reflecting mirror 24 is provided at 45 ° to the vertical axis.
The X-ray beam can be introduced from outside the axis of the X-ray beam, and the X-ray beam path 23 can be introduced.
The laser light can pass along.

First, the edge position of the knife edge system 21 is set to the center position of the X-ray beam. next,
The difference between the position of a certain dark line in the diffraction pattern formed by the edge of the knife edge system 21 and the position of the geometric shadow is calculated in advance, and the position of the edge of the rear edge plate system 22 is determined. Is moved so as to be at the position of the dark line of the diffraction pattern. In order for the laser light from the laser 25 to follow the path 23 of the X-ray beam, the direction of the laser 25 is adjusted so that exactly half of the spot of the laser light is projected on the surface of the edge plate of the knife edge system 21. , So that the dark line of the diffraction pattern generated thereby is located at the edge position of the knife edge system 22. This will cause the laser 2 to move vertically
This means that the laser beam from No. 5 and the X-ray optical path 23 coincide.

The horizontal direction may be adjusted by adding a knife edge system for measuring the position of the X-ray beam in the horizontal direction, as in the case of adjusting the vertical direction. If it is known, the laser 25 may be rotated in the horizontal plane by the automatic level and aligned. If the laser beam is displaced in parallel in the horizontal plane, the edge plate may be retracted from the optical path, and the laser 25 may be moved horizontally while confirming the position of the laser beam by the reflecting mirror 26 provided behind. The reflecting mirror 26 may be replaced with a simple screen.

After aligning the laser beam with the optical path of the X-ray beam as described above, the edge plate, the reflecting mirror, and the like are removed from the optical path, and the laser beam is passed and made incident on the optical component to be adjusted. The adjustment of the optical component may be performed by observing the behavior of the laser light introduced as described above after passing through the optical component.

According to this embodiment, a visible light beam such as a laser beam can be made to follow an X-ray beam path which is accurately obtained, and the optical axis of a beam line optical component can be easily adjusted. In the present embodiment, the knife edge system described in Embodiment 1 was used as an X-ray beam profile measuring device. The same effect can be obtained with the configuration described in the second embodiment using a wire.

<Embodiment 7> In the above embodiments, the current flowing through the X-ray shield such as an edge plate or a wire was measured for measuring the intensity profile of the X-ray beam. In the embodiment shown in FIG. 9, an X-ray detector 27 is provided behind the edge plate to measure the X-ray intensity. The X-ray detector 27 is mounted on the support member 28 and is movable in the direction of the arrow in the figure, and can be manually or automatically removed from the X-ray beam path when not needed. If an energy dispersive semiconductor detector or the like is used as the X-ray detector 27, the position and profile of an X-ray beam having desired energy can be measured. According to this embodiment, a signal from the X-ray detector 27 is input to the computer 12 through a signal processing system 29 controlled by the computer 12. According to this embodiment, more accurate X-ray beam position and intensity measurement can be performed. it can. In this embodiment, a knife edge system as described in Embodiment 1 was used as an X-ray beam profile measuring device. The same effect can be obtained with a configuration as described in the second embodiment using a wire.

[0027]

According to the present invention, the position and intensity profile of the X-ray beam from the soft X-ray to the X-ray region in the beam line device can be accurately measured, and the position where the X-ray beam passes has a sharp edge. Since marking can be made in the space by the edge position of the X-ray shield such as a plate or a wire, the optical components of the beam line device can be adjusted quickly and precisely.

[Brief description of the drawings]

FIG. 1 shows an X-ray beam profile measuring apparatus using a knife edge.

FIG. 2 is a diagram showing a current measurement result.

FIG. 3 is an intensity profile diagram.

FIG. 4 is an X-ray beam profile measurement device using a wire.

FIG. 5 shows a configuration of two-dimensional measurement of an X-ray beam intensity profile.

FIG. 6 is an example of an X-ray shield for X-ray beam intensity profile two-dimensional measurement.

FIG. 7 is an embodiment diagram provided with a filter for removing low energy components.

FIG. 8 is a diagram of a laser beam introduction system for adjusting an optical component.

FIG. 9 is a diagram in which an X-ray detector is arranged behind the X-ray beam profile measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... X-ray beam, 2 ... edge plate, 3 ... insulator, 4 ... support member, 5 ... film, 6 ... photoelectron, 7 ... signal line, 8 ... ammeter,
9 ... Straight introducer with motor, 10 ... Driver, 11 ...
Controller, 12 computer, 13 wire, 14 insulator, 15 support member, 16 plate, 17
Edges, 18 frames, 19 filters, 20 support members, 21 knife edge systems, 22 knife edge systems, 23 X-ray beam paths, 24 mirrors, 2
5 laser, 26 reflector, 27 X-ray detector, 28
... Support member, 29 ... Signal processing system.

Claims (14)

[Claims] An X-ray beam from a soft X-ray to a hard X-ray region radiated from a deflecting magnet of an electron storage ring, an insertion light source, a laser plasma X-ray source, or the like, is transmitted to a sample via a beam line device. X-rays that automatically or manually move an X-ray shield for measuring a passing position or a cross-sectional shape of the X-ray beam so as to irradiate the X-ray beam at a desired position. Optical axis adjustment device. 2. The X-ray term axis adjusting device according to claim 1, wherein the X-ray shield is a plate having one or more sides of a knife edge. 3. The X-ray term axis adjusting device according to claim 1, wherein the X-ray shield is a wire. 4. One or more Xs according to claim 1
An optical axis adjusting device, wherein a moving direction of the line shield is two directions crossing the X-ray beam and orthogonal to each other. 5. The X-ray shield according to claim 1, wherein said X-ray shield is installed at a plurality of positions on an optical axis for measuring an optical axis position of said X-ray beam, and said X-ray beam has a sectional shape. An X-ray optical axis adjusting device, which is installed at a plurality of positions on an optical axis for measurement. 6. A filter for removing radiation of unnecessary energy is disposed on the light source side of the X-ray shield according to claim 1, and the position or type of the filter can be adjusted automatically or manually. An X-ray optical axis adjustment device, characterized in that: 7. An X-ray optical axis adjusting device according to claim 6, wherein the filter transmits only high energy X-ray components. 8. The filter according to claim 7, wherein the filter is Be, Al,
An X-ray optical axis adjustment device that is a foil of Ti, Ni, BN, Fe, Cu, C, Si, etc. 9. The X-ray detector according to claim 1, wherein an X-ray detector is arranged on a side opposite to the light source with respect to the X-ray shield.
Line optical axis adjustment device. 10. The method according to claim 1, wherein a conductive X-ray shield is insulated and attached to the support rod, and a current flowing through the X-ray shield by X-ray irradiation is detected by an ammeter or the like. 8. The X-ray optical axis adjusting device according to 8. 11. An X-ray optical axis adjusting device according to claim 10, wherein a substance having a high photoelectron generation efficiency, such as gold, platinum or silver, is deposited on the X-ray shield. 12. A mirror capable of introducing a laser beam along an optical axis of an X-ray beam is disposed on a light source side of an X-ray shield position, and on a side opposite to the light source with respect to the X-ray shield position, 12. The X-ray optical axis adjusting device according to claim 1, wherein an apparatus for observing the introduced laser light is provided, and the passage of the X-ray beam can be simulated by the laser light. 13. An X-ray optical axis adjusting device according to claim 12, wherein the device for observing the introduced laser beam is a mirror for deflecting the laser beam outside the optical axis of the X-ray beam. Optical axis adjustment device. 14. An X-ray optical axis adjusting apparatus according to claim 13, wherein the apparatus for observing the introduced laser beam is a screen whose laser spot can be observed from outside the optical axis of the X-ray beam. Line optical axis adjustment device.