JP2014022109A - X-ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray generator capable of adjusting a collision position of electrons emitted from a cathode to an anode.
A cathode 3 that emits electrons 4, an anode 6 that generates X-rays when the electrons 4 emitted from the cathode 3 collide, and an electromagnet 13 are provided. The cathode 3 and the anode 6 are provided in the vacuum chamber, and the electromagnet 13 is provided outside the vacuum chamber. By causing the magnetic field generated by the electromagnet 13 to act on the electrons 4 from the outside of the vacuum chamber, the collision position of the electrons 4 with respect to the anode 6 can be adjusted.
[Selection] Figure 4

Description

  The present invention relates to an X-ray generator having a cathode that emits electrons and an anode that generates X-rays when electrons emitted from the cathode collide in a vacuum chamber.

  FIG. 7 illustrates the configuration of a general rotating anti-cathode X-ray generator. An X-ray generator 30 shown in FIG. 7 has a columnar shape that generates X-rays 34 when a cathode (filament) 33 that emits electrons 32 and an electron 32 emitted from the cathode 33 collide in a vacuum chamber 31. Alternatively, a disc-shaped anode 35 is provided. The outer peripheral surface of the anode 35 forms a target surface 35 a on which the electrons 32 emitted from the cathode 33 collide. A rotation mechanism (not shown) for rotating the anode 35 about the shaft 35b is provided outside the vacuum chamber 31. The X-ray generator 30 generates X-rays 34 by causing electrons 32 emitted from the anode 35 to collide with a target surface 35a of the anode 35 rotating at high speed. The generated X-ray 34 is emitted from the window 36 of the vacuum chamber 31.

  This X-ray generator 30 is used as an X-ray source of an X-ray diffractometer. The X-ray diffractometer is an apparatus for examining the crystal structure of a sample by utilizing an X-ray diffraction phenomenon. An X-ray diffractometer 40 illustrated in FIG. 8 includes an X-ray generator 30 that is an X-ray source, a mirror 42 that reflects X-rays 34 emitted from the X-ray generator 30 toward a sample 41, and a mirror 42. A mirror table 43 to be held, a sample table 44 to hold the sample 41, and an X-ray detector 46 that detects diffracted X-rays 45 b from the sample 41 are provided. The sample stage 44 and the X-ray detector 46 are mounted on a goniometer 47. The goniometer 47 is a device for changing the relative positional relationship among the mirror table 43, the sample table 44, and the X-ray detector 46. The X-ray generator 30, the mirror base 43, and the goniometer 47 are accurately positioned and fixed on the same base 48. The sample 41 is accurately positioned and held on the rotation center axis of the goniometer 47.

  According to the X-ray diffraction apparatus 40 illustrated in FIG. 8, the goniometer 47 is rotated to change the relative positional relationship among the mirror table 43, the sample table 41, and the X-ray detector 46. The intensity of the diffracted X-ray 45b from the sample 41 is detected while changing the angle formed by the incident X-ray 45a directed from 30 to the sample 41 via the mirror 42 and the diffracted X-ray 45b directed from the sample 41 to the X-ray detector 46. can do.

  In the X-ray diffractometer 40 illustrated in FIG. 8, the X-ray diffraction measurement is performed after the relative positions of the X-ray generator 30, the mirror 42, the sample 41, and the X-ray detector 46 are accurately adjusted on the base 48. Is made.

  However, since the temperature inside the X-ray generator 30, particularly the cathode 33 and the vicinity thereof, becomes high, the position of the cathode 33 with respect to the anode 35 may change due to the influence of heat or replacement of components for maintenance. When the relative position between the anode 35 and the cathode 33 changes, the collision position of the electrons 32 against the anode 35 changes, so that the angle of the X-ray 34 from the X-ray generator 30 toward the mirror 42 changes.

  For this reason, no matter how accurate the relative position adjustment between the X-ray generator 30 and the mirror 42 is performed, the angle of the X-ray 34 from the X-ray generator 30 toward the mirror 42 changes after the position adjustment. As a result, the incident angle and the incident position of the X-ray 34 on the mirror 42 change, and the X-ray 45a may not be accurately irradiated onto the sample 41 in some cases. In such a case, in the conventional X-ray diffractometer 40, the relative position between the X-ray generator 30 and the mirror 42 has to be readjusted.

  The problem to be solved by the present invention is to provide an X-ray generator capable of adjusting the collision position of electrons emitted from the cathode to the anode to an appropriate position from the outside of the vacuum chamber, and an X-ray diffractometer provided with the same. There is.

  In order to solve the above problems, the present invention employs the following means.

[X-ray generator]
An X-ray generator according to a first aspect of the present invention is an X-ray generator including a cathode that emits electrons and an anode that generates X-rays when electrons emitted from the cathode collide in a vacuum chamber. And an electron collision position adjusting means capable of adjusting an electron collision position with respect to the anode by applying a magnetic field to the electrons emitted from the cathode from the outside of the vacuum chamber.

  In the X-ray generator of the first invention configured as described above, when the collision position of the electrons emitted from the cathode with respect to the anode is displaced from an appropriate position for some reason, the electron emitted from the cathode is subjected to a vacuum chamber. By applying a magnetic field from the outside, it is possible to adjust the collision position of electrons to the anode to an appropriate position.

The X-ray generator of the second invention is provided with a rotation mechanism for rotating the anode around the axis on the premise of the X-ray generator of the first invention,
The anode has a cylindrical target surface provided coaxially with the axis,
The electron collision position adjusting means is configured to be capable of adjusting an electron collision position with respect to the anode in a circumferential direction or an axial direction of the target surface.

  In the X-ray generator of the second invention configured as described above, when the collision position of the electrons emitted from the cathode with respect to the anode is displaced from an appropriate position for some reason, the electron emitted from the cathode is subjected to a vacuum chamber. By applying a magnetic field from the outside, it is possible to adjust the collision position of the electrons to the anode to an appropriate position by moving in the circumferential direction or the axial direction of the target surface.

  In the X-ray generator of the third invention, on the premise of the X-ray generator of the first or second invention, the electron collision position adjusting means includes an electromagnet or a permanent magnet as the magnetic field generation source. It is a feature.

  In the X-ray generator of the third invention configured as described above, when the collision position of the electrons emitted from the cathode with respect to the anode is displaced from an appropriate position for some reason, the electrons emitted from the cathode are electromagnetized. Alternatively, the collision position of electrons with respect to the anode can be adjusted to an appropriate position by applying a magnetic field generated from a permanent magnet from the outside of the vacuum chamber.

[X-ray diffractometer]
An X-ray diffractometer of the present invention includes an X-ray generator according to any one of claims 1 to 3, a mirror that reflects X-rays emitted from the X-ray generator toward a sample, and a mirror that holds the mirror A table, a sample table for holding the sample, and an X-ray detector for detecting diffracted X-rays from the sample.

  In the X-ray diffractometer configured as described above, the collision position of the electrons emitted from the cathode with respect to the anode is displaced from an appropriate position for some reason, so that the X-ray is not accurately irradiated to the sample. In this case, a magnetic field is applied to the electrons emitted from the cathode from the outside of the vacuum chamber so that the collision position of the electrons with respect to the anode is adjusted to an appropriate position so that the X-ray is accurately irradiated to the sample. Therefore, it is not necessary to readjust the relative position between the X-ray generator and the mirror.

  According to the present invention, by applying a magnetic field to the electrons emitted from the cathode from the outside of the vacuum chamber, the collision position of the electrons with the anode can be adjusted to an appropriate position.

Sectional drawing which shows an example of embodiment of the X-ray generator of this invention The perspective view which shows an example of the X-ray generator of this invention The perspective view which visualized the internal structure of the electronic collision position adjustment apparatus in FIG. The perspective view which illustrates the positional relationship of the cathode and anode provided in the vacuum chamber, and the electromagnet provided in the exterior of the vacuum chamber Sectional drawing of the X-ray generator which shows the relationship between the change of the collision position of the electron with respect to an anode, and the change of the outgoing axis of the X-ray generated from an anode Explanatory diagram of electron irradiation area on target surface of anode Sectional view illustrating the configuration of a known X-ray generator A plan view illustrating the configuration of a known X-ray diffractometer

Embodiments of the present invention will be described below with reference to the drawings.
[X-ray generator]
An X-ray generator 1 shown in FIG. 1 includes a cathode 3 that emits electrons in a vacuum chamber 2, and a cylindrical anode 6 that generates X-rays 5 by collision of electrons 4 emitted from the cathode 3. It has. The outer peripheral surface of the anode 6 forms a target surface 7 on which the electrons 4 emitted from the cathode 3 collide. A rotating mechanism 8 that rotates the anode 6 about the axis 6a is provided outside the vacuum chamber 2. The X-ray generator 1 generates X-rays 5 by causing electrons emitted from the cathode 3 to collide perpendicularly with the target surface 7 of the anode 6 that rotates at high speed. The generated X-ray 5 is emitted from the window 9 of the vacuum chamber 2. The radiation angle θ of the X-rays 5 radiated from the target surface 7 is about 6 °. For this reason, the aspect ratio of the irradiation region 10 of the electrons 4 on the target surface 7, that is, the circle of the target surface 7, so that the cross-sectional shape of the X-ray 5 (the shape of the cross section orthogonal to the emission direction) is substantially circular. The ratio of the length L1 in the circumferential (tangential) direction to the length L2 in the axis 6a direction is controlled to 1:10 (see FIG. 6).
The basic configuration described above is almost the same as that of a conventional X-ray generator.

  In addition to the above basic configuration, the X-ray generator 1 of the present invention can adjust the collision position of the electrons 4 against the anode 6 by applying a magnetic field to the electrons 4 emitted from the cathode 3 from the outside of the vacuum chamber 2. An electronic collision position adjusting device 11 is provided.

  As shown in FIG. 2, the electron collision position adjusting device 11 is provided adjacent to the rotation mechanism 8. The electron collision position adjusting device 11 has a rectangular parallelepiped vertical casing 12 and, as shown in FIG. 3, an electromagnet 13 that is a magnetic field generation source in the casing 12. The electromagnet 13 is connected to a magnetic field control circuit (not shown). The magnetic field control circuit is a control circuit for controlling the intensity and polarity of the magnetic field by adjusting the intensity and direction of the current flowing through the coil of the electromagnet 13. The entire rear surface of the housing 12 is open, and the open portion is joined to the vacuum chamber 2.

  The casing 12 is provided with an electromagnet moving device 14 for moving the electromagnet 13 in the left-right direction (X-axis direction) and the up-down direction (Y-axis method). The electromagnet moving device 14 includes an electromagnet holding body 15 holding the electromagnet 13, an X-axis fine adjustment mechanism 16 for finely adjusting the position of the electromagnet holding body 15 in the X-axis direction, and the position of the electromagnet holding body 15. And a Y-axis fine adjustment mechanism 17 for fine adjustment in the Y-axis direction. The X-axis fine adjustment mechanism 16 includes an X-axis direction fine adjustment screw 18 and an X-axis direction elastic support mechanism 21. The Y-axis fine adjustment mechanism 17 includes a Y-axis direction fine adjustment screw 19 and a Y-axis direction elastic support mechanism 22. The X-axis direction fine adjustment screw 18 and the Y-axis method fine adjustment screw 19 are feed screw type fine adjustment screws that are manually operated to rotate. Move forward and backward in the direction and the Y-axis direction. The electromagnet holder 15 is supported by the X-axis elastic support mechanism 21 so as to be displaceable in the X-axis direction, and is supported by the Y-axis elastic support mechanism 22 so as to be displaceable in the Y-axis direction. The electromagnet holder 15 is pressed against the tip end 18 a of the X-axis direction fine adjustment screw 18 by the X-axis direction elastic support mechanism 21, and at the tip 19 a of the Y-axis direction fine adjustment screw 19 by the Y-axis direction elastic support mechanism 22. It is pressed. The tips 18a and 19a of the fine adjustment screws 18 and 19 and the electromagnet holder 15 are slidable with respect to each other. When the X-axis direction fine adjustment screw 18 is turned, the tip 18a moves forward and backward, so that the electromagnet holding body 15 moves with a slight movement amount in the X-axis direction. When the Y-axis direction fine adjustment screw 19 is turned, the tip 19a moves forward and backward, so that the electromagnet holder 15 moves with a slight movement amount in the Y-axis direction. Therefore, by operating both fine adjustment screws 18 and 19, the relative position of the electromagnet 14 with respect to the cathode 3 and the anode 6 can be finely adjusted in the X-axis direction and the Y-axis direction.

  Since the X-ray generator 1 configured as described above includes the electromagnet 13 outside the vacuum chamber 2, a magnetic field is applied to the electrons 4 emitted from the cathode 3 from the outside of the vacuum chamber 2, so that the anode The trajectory of the electrons 4 reaching 6 can be changed. Then, the intensity and polarity of the magnetic field generated by the electromagnet 13 are adjusted, and the position of the electromagnet 14 with respect to the cathode 3 and the anode 6 is adjusted in the X-axis direction and the Y-axis direction as shown in FIG. The direction and magnitude of the trajectory change can be adjusted.

  Therefore, according to this X-ray generator 1, when the collision position of the electrons 4 emitted from the cathode 3 to the anode 6 is displaced from an appropriate position for some reason, a magnetic field is applied from the outside of the vacuum chamber 2, By adjusting the direction and magnitude of the change in the trajectory of the electrons 4 in the X-axis direction and the Y-axis direction, the collision position of the electrons 4 with respect to the anode 6 can be moved in the circumferential direction or the axial direction of the target surface 7 so as to be appropriate. Can be adjusted to the position.

[X-ray diffractometer]
The X-ray diffractometer of the present invention can be realized by using the X-ray generator 1 of the present invention instead of the X-ray generator 30 in the X-ray diffractometer 40 illustrated in FIG. That is, the X-ray diffractometer of the present invention includes the X-ray generator 1, the mirror 42 that reflects the X-ray 34 (5) emitted from the X-ray generator 1 toward the sample 41, and the mirror that holds the mirror 42. A stage 43, a sample stage 44 that holds the sample 41, and an X-ray detector 46 that detects diffracted X-rays 45 b from the sample 41 are provided. The X-ray generator 1, the mirror base 43, and the goniometer 47 are accurately positioned and fixed on the same base 48. The sample 41 is accurately positioned and held on the rotation center axis of the goniometer 47.

  In the X-ray generator 1, when the collision position of the electrons 4 emitted from the cathode 3 to the anode 6 is displaced from an appropriate position for some reason, the X-ray 34 (5) emitted from the X-ray generator 1 is emitted. The axis is displaced. As a result, the incident angle of the X-ray 34 (5) to the mirror 42 changes, and the X-ray 45a (5) reflected by the mirror 42 is not accurately irradiated to the sample 41. Even in such a case, the X-ray diffractometer of the present invention causes the electron 4 emitted from the cathode 3 to act on the magnetic field of the electromagnet 13 from the outside of the vacuum chamber 2 so that the collision position of the electron 4 with the anode 6 is appropriate. By adjusting the position, it is possible to accurately irradiate the sample 41 with the X-ray 45a (5).

  As shown in FIG. 5, due to the curvature of the target surface 7, when the collision position of the electrons 4 is displaced in the circumferential direction of the target surface 7, as shown by a solid line arrow and broken arrows above and below it in FIG. 5 is also displaced vertically (in the X-axis direction). Further, as shown in FIG. 6, the irradiation region 10 of the electrons 4 on the target surface 7 is formed long in the direction of the axis 6 a of the anode 6 and short in the circumferential direction, so that the collision position of the electrons 4 is the axis 6 a of the anode 6. The displacement in the circumferential direction has a greater effect on the displacement of the emission axis of the X-ray 34 (5) than in the displacement in the direction. For this reason, the trajectory of the electrons 4 from the cathode 3 to the anode 6 is adjusted in the Y-axis direction (see FIG. 4) by the magnetic field of the electromagnet 13 to displace the collision position of the electrons 4 in the circumferential direction of the target surface 7. Thus, the X-ray 34 (5) is incident on the mirror 42 so that the X-ray 34a (5) is most effectively adjusted to accurately irradiate the X-ray 45a (5) sample 41. Can do. Since the emission axis of the X-ray 34 (5) can be adjusted in the X-ray generator 1, there is no need to readjust the relative position between the X-ray generator 1 and the mirror 42 or the like.

  In the above-described embodiment, an electromagnet is used as a magnetic field generation source. However, a permanent magnet can be used as a magnetic field generation source. By using a permanent magnet, the magnetic field control circuit can be omitted.

DESCRIPTION OF SYMBOLS 1 X-ray generator 2 Vacuum chamber 3 Cathode 4 Electron 5 X-ray 6 Anode 6a Axis 7 Target surface 8 Rotating mechanism 9 Window 41 Sample 42 Mirror 43 Mirror stand 44 Sample stand 46 X-ray detector 47 Goniometer 48 Base

Claims (4)

In an X-ray generator comprising: a cathode that emits electrons in a vacuum chamber; and an anode that generates X-rays when electrons emitted from the cathode collide with each other.
An X-ray generating apparatus comprising: an electron collision position adjusting means capable of adjusting an electron collision position with respect to the anode by applying a magnetic field to the electrons emitted from the cathode from the outside of the vacuum chamber. A rotation mechanism for rotating the anode around an axis;
The anode has a cylindrical target surface provided coaxially with the axis,
The X-ray generator according to claim 1, wherein the electron collision position adjusting means is capable of adjusting an electron collision position with respect to the anode in a circumferential direction or an axial direction of the target surface.   The X-ray generation apparatus according to claim 1, wherein the electron collision position adjusting means includes a permanent magnet or an electromagnet as a generation source of the magnetic field.   The X-ray generator according to any one of claims 1 to 3, a mirror that reflects X-rays emitted from the X-ray generator toward a sample, a mirror table that holds the mirror, and a sample table that holds a sample And an X-ray detector for detecting diffracted X-rays from the sample.

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