JP3704582B2 - Ion beam collimator for particle induced X-ray analyzer - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an analyzer that introduces an ion beam from a cyclotron through a transfer duct into an analysis chamber and irradiates a sample to perform particle-induced X-ray analysis. Therefore, it is easy to switch between two types of ion beam passage holes of different sizes, and the position and angle of the passage hole are adjusted to adjust the axis of the ion beam. The present invention relates to a collimator that can be accurately matched.
[0002]
[Prior art]
There are two types of ion-excited PIXE analysis performed using a particle-induced X-ray analyzer: wavelength dispersion X-ray analysis and energy dispersion X-ray analysis. The wavelength dispersive X-ray analysis method is suitable for analyzing light elements, and the energy dispersive X-ray analysis method is suitable for analyzing elements having an atomic number of 13 or more. In the energy dispersive X-ray analysis method, an ion beam having an accurate contour and a cross section of a few millimeters in diameter is irradiated on the analysis sample, whereas in the wavelength dispersive X-ray analysis method, the diameter has as sharp a contour as possible. Irradiate an ion beam with a cross section of about several tenths of a millimeter. Practically, the same analyzer is often used to test by changing the analysis method sequentially or alternately using the characteristics of both analysis methods. Therefore, it is necessary to switch the diameter of the irradiation ion beam between a large diameter and a small diameter as needed. This switching is performed by exchanging a collimator that mechanically shapes the cross-sectional shape of the ion beam, but this exchanging operation is not easy.
The collimator is usually composed of a carbon plate with a thickness of about 1 to 3 mm, and is fixed in the middle of the ion beam transfer duct, but the direction of travel of the ion beam and the center of the transfer duct do not exactly match. Therefore, for example, in order to obtain an ion beam with a small diameter of 0.1 mm or less, if the beam passage hole of the collimator is made the same diameter, the ion beam collides with the inner wall surface of the hole, and the ratio of lost ions increases. At the same time, there is a difficulty that the ion beam is deflected by the influence of the edge of the hole.
[0003]
[Problems to be solved by the invention]
Therefore, according to the present invention, it is easy to switch between two types of ion beam passage holes having different diameters, and the position and direction of the ion beam passage hole are precisely matched with the position and traveling direction of the ion beam. It is an object to provide an ion beam collimator for a particle-induced X-ray analyzer that can be adjusted.
[0004]
[Means for Solving the Problems]
In the present invention, in order to solve the above problems, the ion beam collimator 1 is configured by the case 2, the slit body 3 and the slit shaft 4 provided in the case 2. The case 2 is fitted with the first passage hole 6 for the ion beam, the fitting hole 7 in the direction orthogonal to the axis ZZ of the first passage hole 6, and the first passage hole 6. A through-hole 8 is provided in a direction orthogonal to both axes ZZ and XX of the hole 7 so that the axis ZZ of the first passage hole 6 is aligned with the line center of the transfer duct and fixed. did. The slit body 3 is fitted in the fitting hole 7 of the case 2 in an airtight manner so as to be movable in the direction of the axis Y-Y and rotatable about the axis, and the second passage hole for the ion beam communicating with the first passage hole 6. 9 and a bearing hole 10 that is orthogonal to the axis ZZ of the second passage hole 9 and communicates with the through hole 8 of the case 2. The slit shaft 4 is fitted in the bearing hole 10 of the slit body 3 in an airtight manner so as to be movable in the axis Y-Y direction and to be rotatable about the axis, with one end side freely passing through the through hole 8 of the case 2 and outside the case 2. The ion beam third passage hole 12 and the third passage hole 12 of the ion beam orthogonal to each other in the direction orthogonal to the axis so that they can be selectively communicated with the second passage hole 9 of the slit body 3 at a predetermined rotational angle position. A fourth passage hole 13 was formed. Further, a small hole plate 14 having a fifth passage hole 15 for an ion beam having a smaller diameter than that of the fourth passage hole 13 is attached to the ion beam incident side of the fourth passage hole 13 of the slit shaft 4.
[0005]
In the ion beam collimator 1 of the present invention, the third passage hole 12 and the fourth passage hole 13 are selectively communicated with the second passage hole 9 of the slit body 3 by rotating around the axis of the slit shaft 4. By passing the ion beam, the diameter of the cross section of the ion beam is switched between large and small, and it corresponds to the wavelength dispersive X-ray analysis method and the energy dispersive X-ray analysis method. Further, by rotating around the axis of the slit body 3, the ion beam passage holes 9, 12, 13 are deflected so as to be adapted to the irradiation angle of the ion beam running in the transfer duct 52. Further, by moving the slit shaft 4 and the slit body 3 in the directions of the axes YY and XX, the ion beam passage holes 9, 12, and 13 are displaced in the direction orthogonal to the axis ZZ, and the inside of the transfer duct 52 is moved. Adapt to the irradiation position of the running ion beam. Therefore, even if the ion beam passage hole has a small diameter, the ratio of the ions lost by colliding with the inner wall surface of the hole is small, and the ion beam is not deflected by the influence of the edge of the hole.
[0006]
Embodiment
An embodiment of the present invention will be described with reference to the drawings. 1 is a front view of a particle-induced X-ray analysis apparatus to which an ion beam collimator according to the present invention is applied, FIG. 2 is a sectional view of the ion beam collimator according to the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. 4 is an enlarged view taken along the line IV-IV in FIG. 2, and FIG. 5 is an exploded perspective view of the ion beam collimator according to the present invention.
[0007]
1 and 2, an analyzer 51 introduces an ion beam as shown by an arrow A from an ion accelerator (not shown) into an analysis chamber 53 through a duct 52 and irradiates the sample M to induce particle-induced X-rays. Analyze. It is assumed that the ion beam irradiation direction is slightly shifted from the axis Z of the duct 52. The analysis chamber 53 is kept in a vacuum. Reference numeral 54 denotes a focusing electromagnet, which is attached so as to surround the duct 52, and is used to focus the ion beam with the magnetic field. The ion beam collimator 1 according to the present invention is for mechanically shaping the cross section of the ion beam, and is attached in the middle of the duct 52.
[0008]
As shown in FIGS. 2 and 3, the ion beam collimator 1 includes a case 2, a slit body 3 and a slit shaft 4 provided in the case 2.
[0009]
The case 2 has a cylindrical shape and includes flanges 5 for connection to the duct 52 at both ends in the axial direction. The case 2 includes a first passage hole 6 of an ion beam penetrating horizontally in the drawing along the axis, a horizontal fitting hole 7 in the drawing orthogonal to the axis of the first passage hole 6, 1 has a through-hole 8 in the vertical direction in the figure perpendicular to the axes of both the passage hole 6 and the fitting hole 7. The passage hole 6 and the fitting hole 7 are circular in cross section, and the through hole 8 is rectangular in cross section. The fitting hole 7 has a small diameter portion 7b whose diameter is reduced via a step portion 7a on one end side. The outer surfaces of the case 2 in which the fitting hole 7 and the through hole 8 are respectively opened are flat surfaces. The case 2 is fixed so that the axis ZZ of the first passage hole 6 substantially coincides with the axis of the transfer duct.
[0010]
The slit body 3 has a cylindrical shape and is fitted in the fitting hole 7 of the case 2 in an airtight manner so as to be movable in the direction of the axis XX and rotatable about the axis. A small-diameter projection 3a that fits into the small-diameter portion is provided, and a small-diameter cylindrical portion 3b is provided on the other end side. The slit body 3 communicates with the second passage hole 9 for the horizontal ion beam in the figure communicating with the first passage hole 6 and the axis of the second passage hole 9 and communicates with the through hole 8 of the case 2. In the figure, it has a vertical bearing hole 10. The second passage hole 9 and the bearing hole 10 are both circular in cross section. The bearing hole 10 has an annular protrusion 10a on the inner periphery of one upper end side in the drawing. The upper and lower outer surfaces of the slit body 3 are flat in the periphery where the bearing hole 10 is opened.
[0011]
The slit shaft 4 is cylindrical, and is fitted into the bearing hole 10 of the slit body 3 in an airtight manner so as to be movable in the axis Y-Y direction and to be rotatable about the axis. And protrudes out of the case 2. That is, the slit shaft 4 has a large-diameter portion 4a at the other end located in the lower portion in the drawing and is slidably inserted into the bearing hole 10 in an airtight manner, and a small-diameter portion at the upper end side is located above the bearing hole 10. Projecting through the through hole 8 and projecting out of the case 2. A handle 11 for rotating the slit shaft 4 around the axis is fixed to the upper end of the slit shaft 4 located outside the case 2. The slit shaft 4 has a third passage hole 12 (for example, a diameter of 5 mm) and a fourth passage hole 13 (for example, a diameter of 1 mm) for ion beams formed in the large diameter portion 4a in a direction orthogonal to the axis. Have The third passage hole 12 and the fourth passage hole 13 can communicate with the second passage hole 9 of the slit body 3 at a predetermined rotational angle position of the slit shaft 4. Further, the periphery of the opening on the ion beam incident side of the fourth passage hole 13 of the slit shaft 4 is cut into a flat surface, and a small hole plate 14 is attached thereto. The small hole plate 14 is formed with a fifth passage hole 15 for an ion beam having a smaller diameter (for example, 0.1 mm) located at the center of the fourth passage hole 13.
[0012]
Thus, the nut member 16 is attached to the opening on the one end side of the fitting hole 7 of the case 2, and the first adjustment screw 17 is screwed to the nut member 16. The distal end of the first adjustment screw 17 is in contact with the end surface of the small diameter protrusion on one end side of the slit body 3. A spring receiving plate 18 is attached to the opening on the other end side of the fitting hole 7 of the case 2, and between this and the other end surface of the slit body 3, the slit body 3 is always on one end side in the axis XX direction. A spring 19 for biasing is provided. Accordingly, the movement of the slit body 3 in the direction of the axis XX can be adjusted by the advancement and retraction of the first adjustment screw 17.
[0013]
Further, a spring receiving tube 20 is attached to an opening on one end side of the bearing hole 10 of the slit body 3, and the slit shaft 4 is always arranged between the upper end surface of the large-diameter portion 4 a of the slit shaft 4. A spring 21 is disposed to urge the lower end in the Y-Y direction. And the nut member 22 is attached to the other end side opening part of the bearing hole 10 of the slit body 3, and the 2nd adjustment screw 23 is screwed together by this. The tip of the second adjustment screw 23 is in contact with the other end surface of the slit shaft 4. Accordingly, the movement of the slit shaft 4 in the axis Y-Y direction can be adjusted by the advance / retreat of the second adjustment screw 23.
[0014]
A base 24 as a nut member to which the third adjustment screw 25 is screwed is attached to the opening on one end side of the through hole 8 of the case 2. The base 24 is formed with a rectangular opening 24a penetrating vertically in the figure, and the small-diameter portion 4b of the slit shaft 4 penetrates the base 24 with a margin so as to be movable in four directions. The base 24 is formed with screw holes 24b facing each other on both sides of the opening 24a along the axis ZZ in the horizontal direction in the drawing. A third adjusting screw 25 is screwed into each of the screw holes 24 b, and the tips thereof are in contact with the opposite side surfaces of the small diameter portion 4 b of the slit shaft 4. Accordingly, the inclination angle of the slit shaft 4, that is, the rotation angle around the axis of the slit body 3 is adjusted by pressing the third adjusting screw 25 and is fixed at a desired angle.
[0015]
In the ion beam collimator 1 of this embodiment, the slit body 4 is selectively rotated 90 ° around the axis by the handle 11 to selectively rotate the third passage hole 12 and the fourth passage hole 13 to the slit body 3. The second passage hole 9 is communicated with. Thereby, the diameter of the cross section of the ion beam passing through the collimator 1 is switched between large and small, and it corresponds to the wavelength dispersion type X-ray analysis method and the energy dispersion type X-ray analysis method. Further, by rotating around the axis of the slit body 3, the ion beam passage holes 9, 12, and 13 are deflected with respect to the axis ZZ so as to be adapted to the irradiation angle of the ion beam running in the transfer duct 52. This adjustment and fixing of the deflection angle is performed by advancing and retracting the third adjusting screw 25. Further, by moving the slit shaft 4 and the slit body 3 in the directions of the axes YY and XX, the ion beam passage holes 9, 12, and 13 are displaced in the direction orthogonal to the axis ZZ, and the inside of the transfer duct 52 is moved. Adapt to the irradiation position of the running ion beam. The movement of the slit shaft 4 in the direction of the axis YY is performed by the advancement and retraction of the second adjusting screw 23 against the biasing force of the spring 21, and the movement of the slit body 3 in the direction of the axis XX is the biasing force of the spring 19. This is done by advancing and retracting the first adjusting screw 17 that resists this. Therefore, since the passage hole can be accurately matched to the ion beam irradiation angle and position, even if the passage hole has a small diameter, the ratio of ions lost by colliding with the inner wall surface of the hole is small, and the influence of the edge of the hole is affected. In response, the ion beam is not deflected.
[0016]
【The invention's effect】
As described above, in the present invention, the ion beam collimator 1 is configured by the case 2, the slit body 3 and the slit shaft 4 provided in the case 2. The case 2 is fitted with the first passage hole 6 for the ion beam, the fitting hole 7 in the direction orthogonal to the axis ZZ of the first passage hole 6, and the first passage hole 6. A through-hole 8 is provided in a direction orthogonal to both axes ZZ and XX of the hole 7 so that the axis ZZ of the first passage hole 6 is aligned with the line center of the transfer duct and fixed. did. The slit body 3 is fitted in the fitting hole 7 of the case 2 in an airtight manner so as to be movable in the direction of the axis Y-Y and rotatable about the axis, and the second passage hole for the ion beam communicating with the first passage hole 6. 9 and a bearing hole 10 that is orthogonal to the axis ZZ of the second passage hole 9 and communicates with the through hole 8 of the case 2. The slit shaft 4 is fitted in the bearing hole 10 of the slit body 3 in an airtight manner so as to be movable in the axis Y-Y direction and to be rotatable about the axis, with one end side freely passing through the through hole 8 of the case 2 and outside the case 2. The ion beam third passage hole 12 and the third passage hole 12 of the ion beam orthogonal to each other in the direction orthogonal to the axis so that they can be selectively communicated with the second passage hole 9 of the slit body 3 at a predetermined rotational angle position. A fourth passage hole 13 was formed. Further, since the small hole plate 14 having the fifth passage hole 15 of the ion beam having a smaller diameter than the fourth passage hole 13 is attached to the ion beam incident side of the fourth passage hole 13 of the slit shaft 4, the diameter is reduced. It is possible to easily switch between two types of ion beam passage holes of different sizes, and in order to make the direction and position of the ion beam passage hole exactly coincide with the traveling direction and position of the ion beam, the position and angle thereof are changed. There is an effect that fine adjustment can be easily performed.
[Brief description of the drawings]
FIG. 1 is a front view of a particle induced X-ray analyzer to which an ion beam collimator according to the present invention is applied.
FIG. 2 is a cross-sectional view of an ion beam collimator according to the present invention.
3 is a cross-sectional view taken along line III-III in FIG.
4 is an enlarged view taken along the line IV-IV in FIG. 2. FIG.
FIG. 5 is an exploded perspective view of an ion beam collimator according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ion beam collimator 2 Case 3 Slit body 4 Slit shaft 6 Ion beam first passage hole 7 Fitting hole 8 Through hole 9 Ion beam second passage hole 10 Bearing hole 12 Ion beam third passage hole 13 Ion beam fourth passage hole 14 Small hole plate 15 Ion beam fifth passage hole

Claims (6)

An ion beam cross section is provided in the middle of a transfer duct in a particle-induced X-ray analyzer that conducts an analysis by directing an ion beam from a cyclotron through a transfer duct into an analysis chamber and irradiating the sample with the ion beam in the analysis chamber. A collimator for shaping the shape,
A first passage hole for the ion beam, a fitting hole in a direction perpendicular to the axis of the first passage hole, and a through hole in a direction perpendicular to the axes of both the first passage hole and the fitting hole A case that is fixed so that the axis of the first passage hole coincides with the axis of the transfer duct;
A second passage hole of an ion beam that is fitted in the fitting hole in an airtight manner so as to be movable in the axial direction and rotatable about the axis, and communicates with the first passage hole, and an axis of the second passage hole. A slit body that is orthogonal and has a bearing hole that communicates with the through hole of the case;
The slit body is fitted into the bearing hole of the slit body in an airtight manner so as to move in the axial direction and freely rotate around the axis, and one end side freely passes through the through hole of the case and protrudes out of the case. A slit shaft having third and fourth passage holes for ion beams formed orthogonally to each other in a direction orthogonal to the axis so as to selectively communicate with the second passage holes of the body;
A small hole plate attached to the ion beam incident side of the fourth passage hole of the slit shaft and having a fifth passage hole of an ion beam having a smaller diameter than the fourth passage hole;
By rotating around the slit axis, the third and fourth passage holes are switched to pass the ion beam, and by rotating around the slit body axis, the ion beam passage hole is deflected, and the slit An ion beam collimator for a particle-induced X-ray analyzer characterized in that an ion beam passage hole is displaced in the direction orthogonal to the axis by movement of the shaft and the slit body in the axial direction. The axial movement of the slit body is adjusted by pressing a first adjusting screw that is positioned on one end side of the slit body and screwed into a nut member attached to the case. An ion beam collimator for a particle-induced X-ray analyzer described in 1. The particle-induced X according to claim 2, wherein a spring is provided between the other end side of the slit body and the case to constantly bias the slit body in the axial direction toward the one end side. Ion beam collimator for line analyzer. The movement of the slit shaft in the axial direction is adjusted by pressing a second adjustment screw that is positioned on the other end side of the slit shaft and screwed into a nut member attached to the slit body. Item 12. An ion beam collimator for a particle-induced X-ray analyzer according to Item 1. The particle-induced X according to claim 4, wherein a spring that constantly urges the slit shaft toward one end in the axial direction is interposed between one end of the slit shaft and the slit body. Ion beam collimator for line analyzer. The rotation angle around the axis of the slit body is adjusted by pressing a third adjustment screw that is positioned on one end side of the slit shaft and screwed into a nut member attached to the case. 2. An ion beam collimator for a particle-induced X-ray analyzer according to 1.

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