JPH07104297B2 - X-ray analyzer - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray analysis apparatus equipped with a mechanism capable of exchanging a plurality of analyzing crystals.

B. 2. Description of the Related Art In a fluorescent X-ray analyzer equipped with a plurality of (6 to 8) analyzing crystals, a rotating drum type crystal exchanging mechanism is usually used. As shown in FIG. 2, this mechanism mounts 6 to 8 analyzing crystals 2 on a rotating drum type analyzing crystal stage 3.
The dispersive crystal stage 3 is rotated to position one arbitrary dispersive crystal at the use position. And the analyzing crystal stage 3
And the entire switching drive (not shown) that rotates it,
It is possible to rotate along the surface of the dispersive crystal in the use position about the center line of the disperser passing through the center of the surface, and this rotation causes the dispersive crystal in the use position to perform wavelength scanning of the disperser. At this time, it is necessary to rotate the X-ray detector 4 about the spectroscope center 0 by a double angle 2θ with respect to the rotation angle θ of the dispersive crystal. Conventionally, the rotation of the dispersive crystal and the rotation of the detector are It has been designed to be connected by a double angle transmission mechanism, to be driven by one wavelength scanning drive motor, and to detect the wavelength by the rotation amount of this motor.

C. Problems to be Solved by the Invention In order to maintain the spectral accuracy, it is necessary to keep the accuracy of the machining of the drum, the accuracy of the rotational position of the drum, and the accuracy of mounting the dispersive crystal on the base within 1/100 degrees. Therefore, a lot of labor was required for processing, adjustment and inspection. By providing the rotation axis of the drum parallel to the plane including the optical axis of the spectroscope, the influence of the rotation stop position accuracy of the drum on the X-ray spectroscopy accuracy can be significantly reduced. However, regarding the machining accuracy of the drum and the accuracy of mounting the dispersive crystal on the base, there is no simple method for removing the influence on the spectroscopic accuracy. In any case, since it is necessary to adjust the position when the deviation of the setting position of the dispersive crystal is found by dispersing the X-ray of the known wavelength, the fine adjustment is made between the dispersive crystal base and the dispersive crystal stage. A large amount of time and labor is required because a mechanism has to be provided for adjustment, and it is extremely difficult to completely adjust the device. Therefore, a crystal exchange type X-ray analysis device is required. Spectral accuracy was not good.

INDUSTRIAL APPLICABILITY The present invention uses a device in which the processing accuracy of the drum, the accuracy of the rotation stop position of the crystal exchange mechanism, the accuracy of attaching the dispersive crystal to the base, etc. are not particularly high, and the labor time for adjustment is greatly reduced and high. The purpose is to obtain X-ray spectral accuracy.

D. Means for Solving Problems In an X-ray analyzer, a crystal exchange mechanism for alternately installing a plurality of dispersive crystals at the center position of the X-ray spectroscope is provided, and the dispersive crystal located at the center of the spectroscope is the center of the X-ray spectroscope. And a mechanism for rotating the X-ray detector about the center of the X-ray spectroscope independently of each other, and
A position for detecting the rotation angle of the dispersive crystal and the rotational position of the X-ray detector is provided, and the position of the dispersive crystal and the X-ray detector that maximizes the detection output of the characteristic X-ray of the known element, and the dispersive crystal and the X-ray A means for storing the difference from the position corresponding to the X-ray wavelength on the mechanism of the detector is provided, and the offset of the above difference is given to the dispersive crystal at the time of wavelength scanning to drive the dispersive crystal.

E. Effect According to the present invention, since the dispersive crystal and the detector can be independently controlled to rotate in wavelength scanning, the predetermined wavelength position on the mechanism of each dispersive crystal and the X-ray detector and the X-ray detected intensity have the maximum values in the calibration measurement. If the difference from the optimum position is measured, this deviation angle represents the error in the position of the dispersive crystal that integrates the mounting accuracy of the dispersive crystal, the accuracy of the crystal replacement mechanism, etc. Therefore, the deviation angle is taken into consideration by the CPU. By driving the dispersive crystal in this way, fine adjustment of mounting of the dispersive crystal is not required, and even if the processing accuracy of the disperser for the dispersive crystal or the detector driving device is not particularly high,
It has become possible to perform a spectroscopic crystal and an accurate X-ray spectroscopic measurement at the optimum setting position.

F. Embodiment FIG. 1 and FIG. 2 show an embodiment of the present invention. In FIG. 2, S is a sample, E is an X-ray, K is a fluorescent X-ray excited by the X-ray E and emitted from the sample S, 1 is an X-ray tube, 2
Is a dispersive crystal for dispersing the fluorescent X-rays K, 3 is a rotatable dispersive crystal stage on which a plurality of dispersive crystals 2 are installed, and 4 is a detector for detecting the characteristic X-ray T dispersed by the dispersive crystal 2. It is equipped with a mechanism that can rotate around the center 0 of the X-ray spectrometer. The dispersive crystal stage 3 is rotated by a drive device (not shown) so that an arbitrary dispersive crystal can be positioned at a use position.
The whole of the dispersive crystal stage 3 and its driving device can be rotated about the center 0 of the X-ray spectroscope as shown by an arrow, and by this rotation, it is positioned at the use position, that is, the center of the X-ray spectroscope. Wavelength scanning by the dispersive crystal is performed.
In FIG. 1, reference numeral 5 denotes the dispersive crystal rotation driving device for wavelength scanning described above. Reference numeral 6 denotes a detector driving device which rotates the detector 4 around the zero point. A CPU 7 controls the crystal driving device 5 and the detector driving device 6 by using the driving signal generated by the driving signal generator 9 and reads their rotation angles. Reference numeral 8 denotes an angle display device for displaying the rotation angles of the spectroscopic crystal and the detector 4 read by the CPU 7, and the X-ray wavelength converted from these rotation angles.

With the above configuration, the analyzing crystal 2 installed on the analyzing crystal stage 3 such as the LiF (200) plane is positioned at the use position, and its angular position θ is set to the position of θ = 22.515 ° -0.3 ° by the CPU. The characteristic X-ray spectrum of Cu, which is almost in the middle of the usable wavelength range of the crystal, of 2θ = 45.03 ° is detected by driving the detector driving device 6 within the angle range of 2θ ± 0.3 °.
The angular position of the detector 6 having the maximum line intensity is stored in the CPU 7. Next, the analyzing crystal 2 is tilted by 0.05 ° from the above position and the same measurement as above is performed. Similarly, the inclination θ of the analyzing crystal 2 is θ =
Repeat the measurement until it reaches 22.515 ° + 0.3 °. Based on the measurement result, a curve connecting the maximum values of the detection output in each measurement is made as shown in FIG. From this curve, the angular position of the dispersive crystal and the angular position of the detector that maximize the X-ray detection output are determined. This may be done by humans by drawing, but it may be done by setting an appropriate algorithm to the CPU. In this way, the set angle of the dispersive crystal and the set angle of the detector 4 are obtained, and the theoretical positions (θ = 22.515) on the mechanism are calculated.
(2, θ = 45.03 °) is calculated and the CPU7
To memorize. This deviation represents an error in the position of the dispersive crystal. Therefore, when setting the dispersive crystal 2, a position corrected by the deviation from the wavelength position on the mechanism is set as a correct position. Similarly, the calibration measurement is performed on the other analyzing crystal 2.

G. Effect According to the present invention, the rotation of the dispersive crystal and the rotation of the X-ray detector are independently performed, and the structural error is not corrected by the structural adjustment, but the error amount is stored and calculated. Since the correction is performed, even if a dispersive crystal installation stand or a detector driving device whose processing accuracy is not particularly high is used, accurate X-ray spectroscopic measurement can be performed without spending a large amount of time for adjustment. X
It is possible to reduce the cost of line analyzers and improve spectral accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a configuration diagram of this embodiment, and FIG. 3 is a graph showing the result of calibration measurement. 1 ... X-ray tube, 2 ... Spectroscopic crystal, 3 ... Spectroscopic crystal stage, 4
...... Detector, 5 ...... Spectroscopic crystal drive device, 6 ...... Detector drive device, 7 ...... CPU, 8 ...... Angle display device, 9 ...... Drive signal generator, E ...... X-ray, S ...... Sample, K ... Fluorescent X
Line, T ... Characteristic X-ray.

Claims (1)

[Claims] 1. A crystal exchanging mechanism for alternately installing a plurality of dispersive crystals at a center position of an X-ray spectroscope, and means for rotating the dispersive crystal positioned at the center of the spectroscope about the center of the X-ray spectroscope. A mechanism for rotating the X-ray detector about the center of the X-ray spectrometer is provided independently of each other, and means for detecting the rotation angle of the dispersive crystal and the rotation position of the X-ray detector is provided.
A means for storing the difference between the position of the dispersive crystal and the X-ray detector that maximizes the characteristic X-ray detection output of the known element and the position corresponding to the X-ray wavelength on the mechanism of the dispersive crystal and the X-ray detector is provided. ,
X is characterized in that the analyzing crystal is driven by giving an offset corresponding to the above difference to the analyzing crystal during wavelength scanning.
Line analyzer.