JP3593552B2 - Scattered light reduction device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an X-ray spectrometer, and more particularly, to a scattered light reducing device that reduces scattered light of a light beam to collide an ion beam and a light beam.
[0002]
[Prior art]
The double storage ring (DSR) is a double storage ring that intersects at two locations, as schematically shown in FIG. 4, where the radioisotope (RI) and the electrons are accelerated within this ring and the location of the intersection To allow a frontal collision or a side impact collision.
FIG. 5 is a schematic diagram of the planned X-ray spectrometer. In this apparatus, short-lived nuclei are detected and measured by causing an X-ray generated from an electron beam stored in a DSR by using an undulator to collide with an RI beam head-on.
[0003]
[Problems to be solved by the invention]
In the above-mentioned X-ray spectrometer, it is necessary to precisely measure the number of photons (photons) generated at the time of a frontal collision between an X-ray (light beam) and an RI beam (ion beam). However, at this time, unless the scattered light of the light beam before the collision is almost completely removed, there is a problem that the disturbance at the time of photon measurement becomes too large to make the measurement impossible.
[0004]
In other words, precise measurement of the number of photons requires measurement of several orders from the scattered energy at the time of collision, so the light beam before the collision is as narrow as the ion beam, and the scattered light that passes through diffraction is also small. In addition, it is necessary to set the level to a level that does not adversely affect the precise measurement of the number of photons (for example, a scattering rate of 10 ⁻⁹ or less).
Further, the passing position of the ion beam is not exactly at the same position, but is displaced within a plane orthogonal to the beam by a maximum of several millimeters depending on the operation state. Therefore, it is necessary to accurately position the passage position of the light beam before the collision in correspondence with the passage position of the ion beam.
[0005]
The present invention has been made to satisfy the various needs described above. In other words, an object of the present invention is to narrow the light beam before collision, finely position the passing position in a plane orthogonal to the plane, and reduce the passing scattered light to a level that does not adversely affect the precision measurement of photons. An object of the present invention is to provide a scattered light reduction device capable of greatly reducing the amount of scattered light.
[0006]
[Means for Solving the Problems]
The inventors of the present invention set the distance between two anti-scattering devices (aperture devices) at 100 mm, set the transmittance of the upstream light beam to 78%, and set the downstream side to 100%. As a result, it was confirmed that about 0.425% of the first scattered light can be reduced to 0.00013%. This means that the addition of the second aperture device reduces to approximately 1/3270, and the addition of a 100% transmittance aperture device reduces it to at least 10 ^-3 or less per sheet. I have. The present invention is based on such a new finding.
[0007]
That is, according to the present invention, in order to accurately measure the number of photons (photons) generated at the time of a head-on collision between a light beam and an ion beam, scattering to remove almost completely the scattered light of the light beam before the collision is performed. A light reduction device,
A vacuum chamber through which the light beam passes, at least four anti-scattering devices arranged at intervals along the light beam, and a position detection device for detecting a passage position of the light beam,
The anti-scattering device includes a diaphragm device capable of continuously changing the aperture diameter, a traverse device for moving the diaphragm device in a plane orthogonal to the light beam, and a center hole that covers a moving range of the aperture position of the diaphragm device. Consisting of a shielding plate having
The position detecting device has a position detecting plate movably provided between a blocking position for blocking the light beam and a retracted position retracted therefrom,
Each anti-scattering device is separated from each other by at least 100 mm or more ,
The scattering prevention device located on the most upstream side has an aperture diameter and an opening position positioned so as to narrow the light beam narrowly, and the second and subsequent scattering prevention devices pass through the scattering prevention device located on the most upstream side. The scattered light reduction device is characterized in that the aperture diameter and the aperture position are positioned so as to pass almost 100% of the transmitted light beam and almost completely cut off the edge scattered light .
[0008]
According to the configuration of the present invention described above, comprising at least four anti-scatter device, since each anti-scatter device separating at least 100mm or more intervals, at least 10 ^-9 scattered light from the test results described above ( = 10 ⁻³ × 10 ⁻³ × 10 ⁻³ ) or less.
Further, the aperture device of each scattering prevention device can continuously change the aperture diameter, so that the light beam before collision can be arbitrarily narrowed. Further, the diaphragm device can be moved in a plane orthogonal to the light beam by a traverse device, and the position of the light beam can be detected by a position detection plate, so that the passing position can be accurately positioned in the plane orthogonal to the light beam. it can.
[0009]
According to a preferred embodiment of the present invention, the diaphragm device includes a spring-return type lever that continuously changes an opening diameter, a diaphragm opening / closing mechanism that air-tightly operates the lever from outside the vacuum chamber, and a diaphragm device that is orthogonal to the diaphragm device. The traverse device has an elastic guide member for elastically guiding the guide groove and an airtight seal penetrating the vacuum chamber from the opposite side of the elastic guide member. It has an X-direction mechanism and a Y-direction mechanism for moving the aperture device in the X and Y directions.
[0010]
With this configuration, the lever can be operated from the outside of the vacuum chamber by the aperture opening / closing mechanism to adjust the aperture diameter and narrow the light beam. Further, the guide device is moved in the X and Y directions by a guide groove for guiding the diaphragm device in the X and Y directions orthogonal to each other, and the X direction mechanism and the Y direction mechanism for moving the diaphragm device in the X and Y directions. Can be positioned.
[0011]
Preferably, the position detection plate is a fluorescent plate, and an observation window for observing the fluorescent plate is provided in a vacuum chamber. With this configuration, the position of the light beam on the fluorescent plate can be visually confirmed through an observation window or by a CCD camera or the like, and the passing position can be accurately positioned in a plane orthogonal to the fluorescent plate.
[0012]
Preferably, the position detection plate is a CCD, and the position of the anti-scattering device is controlled in accordance with the detection position of the CCD. With this configuration, the positioning of the light beam can be easily automated.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. In addition, the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted.
FIG. 1 is an overall configuration diagram of the scattered light reducing device of the present invention. In this figure, a scattered light reducing device 10 of the present invention includes a vacuum chamber 12 through which a light beam 1 passes, at least four anti-scattering devices 14 arranged at intervals along the light beam 1, a light beam 1 is provided with a position detecting device 16 for detecting the passing position. The anti-scattering devices 14 are separated from each other by at least 100 mm or more.
[0014]
In this drawing, reference numeral 2 denotes an ion beam, 3 denotes a vacuum pump, and 4 denotes a photon detector. The light beam 1 collides with the ion beam 2 in the vacuum chamber 12, and photons generated and scattered at that time are separated by photons. The detector 4 detects it. The light beam 1 is preferably a light beam such as an X-ray or a laser, and the ion beam 2 is preferably an RI beam.
[0015]
The position detecting device 16 has a position detecting plate (not shown) movably provided between a blocking position for blocking the light beam 1 and a retracted position retracted therefrom. In the embodiment shown in FIG. 1, the position detection plate is a fluorescent plate. Further, five observation windows 13 for observing the fluorescent plate are provided in the vacuum chamber 12. The observation window 13 has a transparent glass that is hermetically attached. Through this transparent glass, the position of the light beam 1 on the fluorescent plate (position detection plate) can be confirmed visually or by a CCD camera. With this configuration, the position of the light beam 1 on the fluorescent plate can be visually confirmed through an observation window or by a CCD camera or the like, and the passing position can be accurately positioned in a plane orthogonal to the plane.
[0016]
The present invention is not limited to this configuration. For example, the position detection plate may be a CCD, and the position of the scattering prevention device 12 may be controlled according to the detection position of the CCD. With this configuration, the positioning of the light beam 1 can be easily automated.
[0017]
FIG. 2A is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 2B is a side cross-sectional view of FIG. As shown in this figure, the scattering prevention device 14 includes a stop device 18 that can continuously change the diameter (opening diameter) of the opening 11, and a traverse device 20 that moves the stop device 18 in a plane orthogonal to the light beam 1. And a shielding plate 22 having a center hole 22a covering the moving range of the position of the opening 11 of the diaphragm device 18.
[0018]
The diaphragm device 18 has a spring-return type lever 18a for continuously changing the opening diameter, a diaphragm opening / closing mechanism 19 for operating the lever 18a airtightly from outside the vacuum chamber 12, and a diaphragm device 18 orthogonal to the light beam 1. And a guide groove 18b for guiding in the X and Y directions.
The aperture opening / closing mechanism 19 moves the seal rod 19b in the axial direction, a wire 19a having an inner end connected to the lever 18a, a seal rod 19b having an outer end fixed and hermetically sealed by an O-ring. The moving means 19c (in this example, a male screw and a nut). The seal rod 19b is provided with a groove extending in the axial direction, and is prevented from rotating by a guide bolt 19d fitted in the groove.
[0019]
With the above-described configuration, by moving the seal rod 19b in the axial direction by the moving means 19c (male screw and nut), the opening diameter 11 is adjusted from the outside of the vacuum chamber via the wire 19a and the lever 18a, and the light beam 1 Can be narrowed down.
[0020]
Further, in FIG. 2, the traverse device 20 includes an elastic guide member 24 for elastically guiding the guide groove 18b of the expansion device 18 and an airtight passage through the vacuum chamber 12 from the opposite side of the elastic guide member 24 to the traverse device 20. It has an X-direction mechanism 25 and a Y-direction mechanism 26 for moving in the X and Y directions. The elastic guide member 24 has a built-in compression coil spring 24a therein, and is a pair of hollow tubes 24b formed telescopically with each other, and is urged by the compression coil spring 24a in a direction in which the entire length is extended. The X-direction mechanism 25 and the Y-direction mechanism 26 each have a screw rod sealed with an O-ring, and the inner ends thereof are in contact with the opposite side of the elastic guide member 24 so that the diaphragm device 18 is moved in the X and Y directions. It has become. According to this configuration, the screw rod is rotated, and the diaphragm device 18 is moved in the X and Y directions by the screw rod and the elastic guide member 24, thereby enabling accurate positioning.
[0021]
The center hole 22a of the shielding plate 22 is set to a size that covers the moving range of the position of the opening 11 of the diaphragm device 18. With this configuration, it is possible to prevent the scattered light and the reflected light in the vacuum chamber from passing around the diaphragm device 18 and enhance the effect of reducing the scattered light.
[0022]
With the above-described configuration, it is preferable to set the transmittance of the light beam 1 to an arbitrary value (for example, about 78%) for the scattering prevention device 14 located on the most upstream side, and to set the other scattering prevention devices 14 to approximately 100%. . That is, the transmittance of the first anti-scattering device 14 is not essential, and it is rather important that the transmittance from the second anti-scattering device 14 be almost 100%. This is because most components of the scattered light are edge scattered light generated when the shape of the light is shaped by the first baffle (scatter prevention device). The purpose is to cut off the edge scattered light generated in the above.
[0023]
FIG. 3 shows a test result of the scattered light reducing device according to the present invention. In this figure, the horizontal axis is the scattering angle (deg), the vertical axis is the ratio of scattered photons, and the black circles (black circles) in the figure indicate the case where there is one anti-scattering device 14 (One Buffle), and the white circles (Open circles) show the case where there are two scattering prevention devices 14 (2 Buffles). The interval between the two scattering prevention devices 14 was set to 100 mm, and the transmittance of the light beam 1 was set to 78% on the upstream side and 100% on the downstream side.
[0024]
From the results in FIG. 3, it can be seen that at a scattering angle of about 20 ° or more, the order is approximately 101 for One Buffle and 10 ⁻² for 2 Buffles. More precisely, the first scattered light passing through the upstream anti-scattering device 14 was about 0.425%, and the scattered light then passing through the downstream anti-scattering device 14 was about 0.00013%. . This can be reduced to about 1/3270 by adding a second diaphragm (ie, anti-scattering device 14), and at least 10 ^-3 per sheet by adding a diaphragm with almost 100% transmittance. It turns out that it becomes.
[0025]
According to the configuration of the present invention described above, comprising at least four anti-scatter device 14, by the respective anti-scatter device 14 separates at least 100mm or more intervals, at least 10 ^-9 scattered light from the test results (= 10 ⁻³ × 10 ⁻³ × 10 ⁻³ ) or less.
In addition, the aperture device of each scattering prevention device 14 can continuously change the aperture diameter, so that the light beam before collision can be arbitrarily narrowed. Further, the diaphragm device can be moved in a plane orthogonal to the light beam by a traverse device, and the position of the light beam can be detected by a position detection plate, so that the passing position can be accurately positioned in the plane orthogonal to the light beam. it can.
[0026]
It should be noted that the present invention is not limited to the above-described embodiments and examples, and it is needless to say that various changes can be made without departing from the gist of the present invention.
[0027]
【The invention's effect】
As described above, the scattered light reduction device of the present invention narrows the light beam before the collision, accurately positions the passing position in a plane orthogonal to the light beam, and adversely affects the scattered light passing therethrough to the precise measurement of photons. And has an excellent effect that it can be greatly reduced to a level not exceeding
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a scattered light reduction device of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG. 1 and a side sectional view thereof.
FIG. 3 is a test result of the scattered light reducing device according to the present invention.
FIG. 4 is a schematic view of a double storage ring (DSR).
FIG. 5 is a schematic diagram of an X-ray spectrometer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light beam 2 Ion beam 3 Vacuum pump 4 Photon detector 10 Scattered light reducing device 11 Opening 12 Vacuum chamber 14 Anti-scattering device 16 Position detecting device 18 Aperture device 18a Lever 18b Guide groove 19 Aperture opening / closing mechanism 19a Wire 19b Seal rod 19c Move Means (male screw and nut)
Reference Signs List 20 traverse device 22 shielding plate 22a center hole 24 elastic guide member 25 X-direction mechanism 26 Y-direction mechanism

Claims (4)

A scattered light reducing device for almost completely removing scattered light of a light beam before collision in order to accurately measure the number of photons (photons) generated at the time of head-on collision of a light beam and an ion beam,
A vacuum chamber through which the light beam passes, at least four anti-scattering devices arranged at intervals along the light beam, and a position detection device for detecting a passage position of the light beam,
The anti-scattering device includes a diaphragm device capable of continuously changing the aperture diameter, a traverse device for moving the diaphragm device in a plane orthogonal to the light beam, and a center hole that covers a moving range of the aperture position of the diaphragm device. Consisting of a shielding plate having
The position detecting device has a position detecting plate movably provided between a blocking position for blocking the light beam and a retracted position retracted therefrom,
Each anti-scattering device is separated from each other by at least 100 mm or more ,
The scattering prevention device located on the most upstream side has an aperture diameter and an opening position positioned so as to narrow the light beam narrowly, and the second and subsequent scattering prevention devices pass through the scattering prevention device located on the most upstream side. An aperture diameter and an aperture position are determined so as to allow almost 100% of the transmitted light beam to pass therethrough and almost completely cut off edge scattered light thereof . The diaphragm device includes a spring-return type lever that continuously changes an opening diameter, a diaphragm opening / closing mechanism that air-tightly operates the lever from outside the vacuum chamber, and a guide groove that guides the diaphragm device in orthogonal X and Y directions. And having
The traverse device includes an elastic guide member for elastically guiding the guide groove, an X-direction mechanism for moving the expansion device in the X and Y directions through the vacuum chamber from the opposite side of the elastic guide member in an airtight manner, and a Y-direction mechanism. The scattered light reduction device according to claim 1, further comprising a direction mechanism. The scattered light reduction device according to claim 1, wherein the position detection plate is a fluorescent plate, and an observation window for observing the fluorescent plate is provided in a vacuum chamber. 2. The scattered light reduction device according to claim 1, wherein the position detection plate is a CCD, and the position of the scattering prevention device is controlled according to a detection position of the CCD.

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