JPH03152449A - X-ray spectroscope - Google Patents

Abstract

PURPOSE:To enable highly sensitive and highly accurate measurement in overall wavelength by performing a control in a mechanism for wavelength scanning of a curved crystal so that it is turned finely on an axis vertical to a face of a Rowland circle running through the center of the surface thereof. CONSTITUTION:A wavelength drive shaft 3 is so arranged that a spectroscopic crystal holding base 10 for holding a spectroscopic crystal 2 is moved in a direction thereof with the rotation of a stepping motor 4 to perform a wavelength drive. The crystal 2 is held rotatably on the base 10 centered on a rotating shaft O' (center of surface of crystal 2). An arm 10A integrated with the crystal 2 is connected to a correction base 8 on the base 10 with a spring 9 and the crystal 2 turns with the rotation of a correction screw 7 screwed down on the base 8. The screw 7 is turned with the rotation of the stepping motor 14. In adjustment of a spectroscope, optimal directions of the crystal 2 are detected at wavelength positions by actual measurement to determine a correction value from the directions on the mechanism and the results are stored into a control section 12. Motors 4 and 14 are rotated through drivers 11 and 16 by an output signal of the control section 12 to always position the crystal 2 at the optimum angle.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an X-ray spectrometer.

[Conventional technology]

BACKGROUND ART A concentrated wavelength scanning X-ray spectrometer (hereinafter referred to as a scanner) using a curved crystal as a spectroscopic element is used in an X-ray microanalyzer, a fluorescent X-ray analyzer, and the like. In this scanner, the X-ray scanner incidence point P, the cylindrical curved spectroscopic crystal 2, and the position Q of the X-ray receiving slit are set so that the radius of curvature of the spectroscopic crystal is the diameter, as shown in the second UA. The center O is on the center normal line, and it is symmetrical about the normal line 00' of the spectroscopic crystal on a circle (Roland circle) passing through the surface center 0'' of the spectroscopic crystal, that is, the wavelength drive axis (X-ray irradiation point). While positioning the spectroscopic crystal so that the central plane of the spectroscopic crystal is at an angle θ with respect to the line connecting the center of the surface of the spectroscopic crystal and the line connecting the center point of the spectroscopic crystal and the exit slit is an angle 2θ with respect to the wavelength drive axis, 2 and the position Q of the exit slit.However, when performing wavelength scanning with a scanner with the above structure, it is difficult to match the focusing conditions at all wavelengths due to aberrations. If adjustment is made to obtain high sensitivity on the wavelength side, the sensitivity will deteriorate on the short wavelength side.Additionally, there is a problem in that the peak position deviates from the theoretical wavelength position.

[Invention tries to solve! [11M] An object of the present invention is to provide a scanner that can obtain spectral characteristics with high sensitivity and high aperture at all wavelengths.

[Means to solve the problem]

In a wavelength-scanning X-ray spectrometer in which three points, the center of the spectroscopic crystal, the analysis point on the sample, and the light-receiving slit of the detector, always move on a Rowland circle while maintaining a θ-2θ relationship, the curved crystal is scanned at the wavelength. On the mechanism that performs
A means for moving Dj and a means for controlling the fine rotation means are provided.

[For use]

The present invention provides a micro-rotation means for slightly rotating the spectroscopic crystal attached to the scanner on a wavelength scanning drive mechanism independently of the machine tank, and sets the optimal direction of the spectroscopic crystal for each wavelength in advance and wavelength scanning drive. The deviation from the direction of the spectroscopic crystal determined by the mechanism is measured and stored in the control unit, and based on the direction deviation data stored in the control unit, the control unit adjusts the above-mentioned fine points corresponding to each wavelength position of the wavelength scanning drive mechanism. By driving the rotation means and positioning the spectroscopic crystal at the optimal angle, it is now possible to always position the scanner under optimal spectroscopic conditions and obtain the highest sensitivity at all wavelengths.

【Example】

FIG. 1 shows an embodiment of the present invention. In FIG.
1 is a sample, and 1 is an electron gun that irradiates the sample with an electron beam. 2
is a spectroscopic crystal that separates the X-rays emitted from the sample S, 6 is a light-receiving slit that transmits only the X-rays separated by the spectrometer crystal 2 and focused on the Roland circumference; This is an X-ray detector that detects transmitted X-rays. The spectroscopic crystal 2, the light-receiving slit 6, and the X-ray detector 5 are attached to one link RJR (not shown), and the link fi4tll constantly connects the analysis point P on the sample plane. The center 0° of the spectroscopic crystal surface and the aperture Q of the light receiving slit 6 are located on the circumference of the Rowland circle R, and the light receiving slit 6 spectra While maintaining the angle between the direction to the crystal center point and the axial direction of the wavelength drive axis at 2θ, the angle θ changes in conjunction with the wavelength drive, and the center normal of the spectroscopic crystal always points toward the center of the Rowland circle. It has become. Reference numeral 10 denotes a spectroscopic crystal stand that holds the spectroscopic crystal 2, and is moved by the link mechanism described above to define the position and direction of the spectroscopic crystal. Reference numeral 3 denotes a wavelength drive axis, which performs wavelength drive by moving the spectroscopic crystal holder 10 in the direction of the drive axis by the rotation of the stepping motor 4, and the movement of the link mechanism is interlocked with this wavelength drive. is held on a spectroscopy crystal holder 10 so as to be rotatable about a rotation axis O' that passes through the center of the surface of the spectrometer crystal and is perpendicular to the plane of the drawing.
A is connected to the correction table 8 on the spectroscopic crystal holding table by a spring 9,
The tip of the correction screw 7 screwed into the correction table 8 is the arm 10A.
Since it is in pressure contact with the spectral crystal 2, the rotation of the correction screw 7 causes the spectroscopic crystal 2 to rotate. 5 is an X-ray detector, and a light receiving slit 6
The correction screw 7 located at the rear of the joint 15
The correction screw 7 is rotated by the rotation of the stepping motor 14, and the appropriate direction of the spectroscopic crystal at each wavelength position is detected by actual measurement during scanner adjustment. The amount of correction from above is determined and stored in the control unit 12. Reference numeral 11.16 is a driver that drives the stepping motors 4 and 14 using an output signal from the control unit 12. 1
3 is the control information of the control unit 12, which is the wavelength position of the pIl class 1 element of the spectroscopic crystal 2. This is an input section for inputting the spectroscopic crystal correction angle and the like corresponding to each element.

【effect】

According to the present invention, the direction angle of the scanner's spectroscopic crystal can be adjusted independently of the wavelength scanning drive, so the sensitivity and accuracy of the scanner are further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the arrangement of a scanner. S...Sample, 0...Roland circle center, 0゛...
Rotation axis (center of spectroscopic crystal surface), P...analysis point, Q...
・Light receiving slit hole, 1... Electron gun, 2... Spectroscopic crystal, 3... Wavelength drive axis, 4... Stepping motor,
5... X-ray detector, 6... Light receiving slit, 7...
Correction screw, 8... Correction stand, 9... Spring, 10...
Holding stand, IOA...arm, 11...driver 12
...Control section, 13...Input section, 14...Stepping motor, 15...Joint, 16...Driver

Claims (1)

[Claims] In a wavelength-scanning X-ray spectrometer in which three points, the center of the spectroscopic crystal, the analysis point on the sample, and the light-receiving slit of the detector, always move on a Rowland circle while maintaining a θ-2θ relationship, the curved crystal is scanned at the wavelength. An X-ray device characterized in that the mechanism for performing the X-ray is provided with means for slightly rotating the crystal by an axis passing through the center of the surface of the crystal and perpendicular to the plane of the Rowland circle, and means for controlling the finely rotating means. Spectroscopic device.