JPS61159182A - X-ray analysis instrument - Google Patents

Abstract

PURPOSE:To eliminate the waste of time and to improve the reliability on the result of the measurement by detecting the oscillation of the output of an X-ray detector with the oscillation of the liquid surface of a refrigerant and starting measurement at the point of the time when the oscillation attenuates down to a prescribed level or below. CONSTITUTION:The X-ray detector D is so constituted as to be cooled by liquid nitrogen. A measuring circuit M which measures the count rate of the X-ray detection pulses and a control circuit Com which detects the oscillation of the output owing to the oscillation of the liquid nitrogen from the output of the circuit M are provided. The reference level l of the oscillation and the time T slightly longer than the period of the oscillation are set at prescribed values. The % of the time when the output of the circuit M exceeds the reference level l with respect to the time T is measured and the measurement is started by discriminating that the oscillation ceases upon attainment of the time when the output of the circuit M exceeds the level l at the prescribed % or below during the time T. The wasteful waiting time is thereby eliminated and the excessively fast start of the measurement is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an X-ray analyzer using a liquid nitrogen-cooled semiconductor detector for X-ray detection.

- Conventional technology When measuring with an X-ray analyzer by moving the X-ray detector to a predetermined position on a goniometer that satisfies Bragg's conditions, it is necessary to use a semiconductor detector cooled with liquid nitrogen, etc. as the X-ray detector. When the detector is used, the cooling medium is also moved together with the detector, so when the detector is moved to a predetermined position, the liquid level of the refrigerant fluctuates, and the sensitivity and noise level of the detector fluctuate accordingly. Measurements cannot be taken until the shaking has subsided. Conventionally, the time required for the shaking of the refrigerant liquid level to subside was estimated empirically, a waiting time was set using a timer after the detector was moved, and measurements were taken after the waiting time had elapsed. However, with this method, the waiting time is inevitably set to a long time in favor of reliability, and in reality, the waiting time is often wasted even though the fluctuations in the refrigerant liquid level have subsided. . On the other hand, in an attempt to save time, some people made the mistake of setting the waiting time too short and starting measurements before the shaking had subsided, resulting in uncertain measurements.

No. Problems to be Solved by the Invention The present invention eliminates the waste of time caused by setting the waiting time based on estimates as described above, and also eliminates the need for uncertain measurements that are affected by fluctuations in the refrigerant liquid level. This is what you are trying to prevent from being exposed.

2. Means for solving the problem The fluctuation of the output of the X-ray detector due to the fluctuation of the liquid level of the refrigerant is detected, and the measurement is started when this fluctuation has attenuated to a predetermined level or less.

Since the measurement is started after detecting that the fluctuation in the detector output due to the fluctuation of the working liquid level has actually subsided, there is no wasted waiting time, and the premature start of measurement is also prevented.

Embodiment The drawings show an embodiment of the present invention. X is an X-ray source, S is a sample, G is a goniometer, C is a spectroscopic crystal, and D is an X-ray detector, which is cooled with liquid nitrogen. M is a measurement circuit that measures and outputs the counting rate of X-ray detection pulses.

C (+m is a control circuit that performs operations such as controlling the drive of the X-ray detector 1 spectroscopic crystal, storing and outputting the measurement circuit output to the display device, and determining the measurement start point.The output of the X-ray detector The signal is input to a measuring circuit M and converted into an X-ray intensity value.The control circuit COm reads the output of this measuring circuit and stores it in a memory.

The control circuit com also detects fluctuations in the output due to fluctuations in the liquid nitrogen from the measurement circuit output. Since the period of this shaking is approximately fixed, the shaking is detected as follows. A time T that is slightly longer than the shaking period is set in advance, and the time T is the time when the measurement circuit output exceeds the reference level.
It is repeatedly measured how many chis there are with respect to the time T as one cycle.

As is clear from FIG. 2, when the vibration is large, the time during which the measurement circuit output exceeds the reference level l is 30% or more of T. On the other hand, in a place where the shaking has subsided, the output of the measurement circuit exhibits constant noise and almost never exceeds the reference level l. The reference level j is set in this way. Since the time T is taken approximately at the period of the shaking, regardless of the relationship between this time interval and the phase of the shaking, the output of the measuring circuit during the time T while there is a shaking that exceeds the reference level. This includes phases in which always exceeds the reference level.

Therefore, it can be determined that the shaking has subsided when the time during which the output of the measuring circuit exceeds the reference level during time T becomes less than or equal to a suitably determined value.

According to the present invention, fluctuations in the detector output due to fluctuations in the liquid level of the refrigerant liquid are detected, and measurement is started when it is detected that this has attenuated below a reference level, thereby eliminating unnecessary waiting time. This improves the efficiency of analysis, and the reliability of measurement results improves because measurements are started after detecting that the shaking has subsided sufficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, and FIG. 2 is a graph illustrating an operation for detecting fluctuations in a detector output. Agent: Hiroshi Agata, Patent Attorney Figure 1: Figure 2: 7”0 block diagram of column H on the actual side

Claims (1)

[Claims] A detector cooled using a cooling liquid is used to detect X-rays, and a circuit that detects fluctuations in the output due to fluctuations in the surface of the cooling liquid of the X-ray detector is used, and the output of the circuit is set to a reference level. An X-ray analyzer equipped with a control circuit that starts measurement when it detects that the output of the same circuit has fallen below a reference value.