JPS5838845A - Concave crystal type x ray spectroscope - Google Patents

Abstract

PURPOSE:To elevate the accuracy by computer-control of a positional relation- ship between an X-ray incidence slit, a spectroscopic crystal and an X-rays detection slit with the driving of the spectroscopic crystal and the X-rays detection slit along a mutually independent and linear guide. CONSTITUTION:A crystal base 5 is provided to slide on a guide 4 extended parallel to the X axis and a spectroscopic concave crystal 2 mounted on the base 5 in such a manner as to be rotatable on the axis (passing the X axis) set vertical to the plane of the drawing. A Rowland circule R runs through an X- rays slit 1, a spectroscopic crystal 2, and an X-rays detection slit 10. As the spectroscopic crystal 2 is moved on the X axis along the guide 4, the Rowland circle R shifts in the position and hence, the coordinate (x, y) of the position of the X-rays detection slit can be obtained by calculation by determining the radius of the Rowland circle. Therefore, a higher accuracy can be achieved by performing this calculation with a microcomputer in a control circuit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a straight X-ray spectrometer using a curved crystal.

Conventionally, a curved crystal type X-ray spectrometer mechanically connects an X-ray entrance slit, a spectroscopic crystal, and an X-ray detection slit to each other so that they are located on the circumference of a Rowland circle, and drives them in conjunction with each other. The structure was such that

With this structure, the precision of the positional relationship between the X-ray entrance slit, the spectroscopic crystal, and the X-ray detection slit is determined due to the inevitable play in the mechanism and the rigidity of the mechanical elements, making it difficult to obtain sufficient wavelength measurement accuracy and wavelength resolution. Ta. In particular, increasing the diameter of the Rowland circle improves the theoretical resolution, so X-ray spectrometers with large Rowland circles have been built, but increasing the Rowland circle increases the dimensions of the mechanical elements and increases the rigidity. This actually made stable measurement difficult, and there was a limit to the direction in which the Rowland circle could be made larger.

The present invention eliminates the mechanical connection between the X-ray entrance slit, the spectroscopic crystal, and the X-ray detection slit, and drives the spectroscopic crystal and the X-ray detection slit independently of each other along a linear guide. By providing an X-ray spectrometer that controls the positional relationship of the above-mentioned champion so that it is located on the circumference of a Roland circle with a radius given by a computer, high-precision, high-resolution X-ray spectroscopy can be achieved. It attempts to make it possible. In other words, by eliminating the mechanism that connects the X-ray entrance slit, spectroscopic crystal, and X-ray detection slit, it overcomes the limit of measurement accuracy of 1 resolution due to play between the elements of the mechanism and lack of rigidity of the mechanism elements. Since there are no problems with the rigidity of the elements, it is possible to obtain an X-ray spectrometer with a Rowland circle 5 of arbitrarily large diameter. The present invention will be explained below with reference to Examples.

The drawing shows an embodiment of the invention. Reference numeral 1 denotes an X-ray entrance slit whose position is fixed to a spectrometer frame (not shown). Assume that the X-axis and y-axis pass through X-ray input pair slit) 1. The X-axis is the incident direction of X#, and the spectroscopic crystal 2 is designed to move along this X-axis. That is, reference numeral 4 denotes a guide extending parallel to the X-axis motion, on which the crystal table 5 slides. A curved spectroscopic crystal 2 is attached so as to be rotatable around the center (through which it passes). Reference numeral 7 denotes a feed screw for moving the table 5, which is rotated by a pulse motor 8 to move the table 5 and hence the spectroscopic crystal 2 along the X axis. 9 is spectroscopic crystal 2
A pulse motor rotates the spectral crystal 2 around an axis perpendicular to the plane of the figure, so that the spectroscopic crystal 2 takes the direction corresponding to the current position on the X-axis, that is, the direction toward the center of the Rowland circle at that time. Control the crystal orientation. 10 is X-Y
An X-ray detection slit 11 and an X-ray detector 12 are installed on a moving stage. 13 is a linear guide extending parallel to the X axis, and the y axis slides on this guide.
There is a linear guide 14 extending in a direction parallel to the axis, and
The moving stage 10 slides on this linear guide 14.

15.16 are feed screws in the X-axis direction and y-axis direction, respectively; 17
, 18 are pulse motors that rotate these screws.

The X-ray detection slit 11 and the X-ray detector 12 must always face the spectroscopic crystal 2. For this purpose, a stand 10' is mounted on the X-Y moving stage 10 so as to be rotatable around an axis perpendicular to the paper plane of the figure, a direction rod 19 is passed through this stand, and one end of this rod is attached to the stand 5 for the spectroscopic crystal. It is pivotally attached to the rotation shaft of No. 2.

The X-ray detection slit 11 and the detector 12 are arranged and fixed on the table 10+ in the penetrating direction of the direction rod 19.
Wherever the moving stage 10 is located, the X-ray detection slit and detector 12 are facing toward the spectroscopic crystal 2.

In the figure, R is the assumed Rowland circle, and X-ray entrance pair slit 12 spectroscopic crystal 2. X-ray detection slits 10 are arranged in series. When the spectroscopic crystal 2 is moved along the guide 4 on the X axis, the Rowland circle R changes its position, and the X
The position where the line detection slit 10 should be also changed, and the spectroscopic crystal 2
The coordinates (x, 7) of the position of the X-ray detection slit with respect to the position on the X-axis of is a function of the position of the spectroscopic crystal 2 on the X-axis,
Once the radius of the Rowland circle is determined, it can be calculated. Similarly, the azimuth angle ψ of the spectroscopic crystal can be calculated by determining the radius of the Rowland circle as a function of the position of the spectroscopic crystal 2.

The control circuit 20 performs the above calculations using a microcomputer, and controls the pulse motor 8. 9. The required number of pulses are sent to the laser beam 18 to control the position and direction of the spectroscopic crystal and the position of the X-ray detection slit.

In the above embodiment, the X-ray detection slit 11 and the X-ray detector 1
The direction of the spectroscopic crystal 2 is controlled mechanically, but this also uses a motor to control the direction of the spectroscopic crystal 2.
Since it is preferable to control at 0, a mechanical method as shown in the above embodiment is sufficient. On the contrary, it is also possible to mechanically control the direction of the spectroscopic crystal 2. Furthermore, the movement trajectory of the X-ray detection slit passes through the X-ray entrance slit.
, is long in the direction of the direction line at 45° with respect to the straight direction of the spectroscopic crystal, and is symmetrical with respect to the same direction line, so X-Y
If the X-direction guide of the moving stage is fixed in this direction, and the Y-direction guide perpendicular to the X-direction guide is immersed in the X-direction guide and slides, the span of the Y-direction guide is relatively short. It has the advantage of being flexible, and is particularly suitable for narrowing the Roland radius.

The curved crystal X-ray spectrometer of the present invention has the above-mentioned configuration,
Since no mechanical method is used to interlock the spectroscopic crystal and the X-ray detection slit, the accuracy limit due to the play of the mechanism and the rigidity of the mechanical elements is overcome, and for the same reason, the X-ray spectrometer with a large Rowland circle is It is easy to manufacture, provides a lightweight, highly accurate, and high-resolution X-ray spectrometer, and is unique because the radius of the Rowland circle can be changed simply by changing the coefficient set when calculating the position data of the X-ray detection slit. It has the characteristic that even if a spectroscopic crystal with a radius of curvature is used, it can be immediately used as an X-ray spectrometer.

[Brief explanation of the drawing]

The drawing is a plan view of an X-ray spectrometer according to an embodiment of the present invention. 1...X-ray entrance slit, 2...curved spectroscopic crystal, 1
1... X-ray detection slit, 12... X-ray detector, 1
0...X-Y moving stage, 8, 9, 1f, 1B,...
, pulse motor. Agent: Patent attorney Kosuke Hayashi.

Claims (1)

[Claims] A linear guide that guides the spectroscopic crystal along a straight line passing through the X-ray entrance slit, a motor that is connected to this guide and drives the spectroscopic crystal, and an X-ray detection slit and X-rays placed on an X-Y moving stage. A detector, a motor that drives the stage in the X direction, a motor that drives the stage in the Y direction, a spectroscopic crystal, an X-ray detection slit, and the circumference of a Rowland circle of a given radius that passes through the X-ray entrance slit. A curved crystal type X-ray spectrometer consisting of a control circuit that controls the spectrometer crystal drive motor, a motor that drives the X-Y moving stage in the X direction, and a motor that drives the X-Y movement stage in the Y direction, so that it is always located above. vessel.