JP4560503B2 - Measuring time setting method and fluorescent X-ray analyzer in multi-condition fluorescent X-ray analysis - Google Patents

Description

The present invention relates to a measurement time setting method and a fluorescent X-ray analyzer in multi-condition fluorescent X-ray analysis.

Generally, in the X-ray fluorescence analyzer, as shown in FIGS. 4 and 5, primary X-rays 2 generated in an X-ray tube 1 using rhodium (Rh), molybdenum (Mo), or the like as a target material of the target portion T. When the measurement sample 3 is irradiated, a part of the primary X-ray 2 excites atoms in the measurement sample 3 to generate fluorescent X-rays 4, and most of the remaining primary X-rays 2 are scattered by the measurement sample 3. . Since the energy value of the generated fluorescent X-ray 4 is determined for each element included in the measurement sample 3, the spectrum data has a peak at the energy position corresponding to the element included in the measurement sample 3. . The element contained in the measurement sample 3 can be identified from the position of this peak. In FIG. 4, fluorescent X-rays 4 and scattered X-rays 5 emitted from the measurement sample 3 enter a detector (semiconductor detector) 6 and are converted into electrical signals. Thereafter, it enters the multichannel analyzer 7 through the amplifier 6a, and an energy spectrum is obtained. In the X-ray tube 1 of FIG. 5, the primary X-ray 2 is generated when electrons e ⁻ accelerated from the filament F by the tube voltage E applied to the target portion T of Rh enter the target portion T. .

  In this way, the primary X-ray 2 emitted from the X-ray tube 1 is irradiated onto the measurement sample 3, the fluorescent X-ray 4 emitted from the measurement sample 3 is detected by the detector 6, and the signal is signal processing means 6 a, In detecting an element contained in the measurement sample 3 by reading as an energy spectrum through 7, Na, Mg having atomic numbers of, for example, 11, 12, 13, 14, 15, 16, and 17, respectively. , Al, Si, P, S, Cl, and other light elements having relatively small atomic numbers, and the atomic numbers are, for example, 38, 39, 40, 41, 42, 46, 47, 49, 50, 51, 74 , 78, 79 and 82, respectively, Sr, Y, Zr, Nb, Mo, Pd, Ag, In, Sn, Sb, W, Pt, Au and Pb, etc. X-ray tube 1 tube The voltage E is detected by using two conditions of a low tube voltage (hereinafter simply referred to as a low voltage) and a high tube voltage (hereinafter simply referred to as a high voltage).

  Conventionally, in FIG. 3, measurement is started in step 301, and after a predetermined measurement time Ta (second) is set in advance in step 302 by the operator, measurement of Ta / 2 (second) is performed at a high voltage in step 303. Then, in step 304, Ta / 2 (seconds) is measured at a low voltage, and these results are combined to simultaneously qualify multi-elements contained in the measurement sample 3 (see step 305). Then, those quantitative calculations are performed (see step 306), and if the quantitative accuracy is satisfactory (see step 307) as determined by the operator (see step 307), the measurement is finished (see step 308). However, if the quantitative accuracy is not satisfactory in step 307, the operator newly sets the measurement time to Tb (seconds) and returns to step 303 to start measurement from high voltage measurement.

  However, since the ratio between the low voltage measurement time and the high voltage measurement time is fixed at 1: 1 within a certain measurement time Ta, the heavy elements that are mainly detected in the high voltage measurement are detected more efficiently than the light elements. Despite being good, it takes the same amount of time as low-voltage measurement, which mainly detects light elements, to high-voltage measurement. Will be spent. That is, in order to increase the accuracy of light element detection at a low voltage, it is necessary to extend the measurement time of the high voltage.

  In addition, when the measurement time is set to Ta seconds as described above, and the ratio of the time for low voltage measurement and the time for high voltage measurement in the measurement time is the same, the quantitative value of the measurement result is temporarily assumed. When the standard deviation σ (the square root of the primary X-ray count) is large and it is desired to reduce it, it is necessary to newly set the measurement time.

The present invention can obtain measurement results with good detection efficiency in a short time in a multi-condition fluorescent X-ray analysis in which quantitative values of light elements and heavy elements are detected by using two conditions of low voltage and high voltage, It is an object of the present invention to provide a measurement time setting method and a fluorescent X-ray analyzer in multi-condition fluorescent X-ray analysis that can set an appropriate measurement time that can reduce the standard deviation of the quantitative value of the measurement result.

In order to achieve the above object, the measurement time setting method in the multi-condition fluorescent X-ray analysis of the present invention is such that primary X-rays emitted from an X-ray tube with a low tube voltage and a high tube voltage are applied to a measurement sample, The fluorescent X-rays emitted from the measurement sample are detected by a detector, and the signal is read as an energy spectrum through the signal processing means, so that the light element and heavy element contained in the measurement sample are reduced to the low tube voltage and A measurement time setting method in a multi-condition fluorescent X-ray analysis for measuring at a high tube voltage, which calculates a standard deviation of each element qualitatively measured by a measurement at a set initial measurement time, and calculates a standard deviation of each element. High tube voltage or low tube voltage is obtained by irradiating the primary X-ray by extending the micro measurement time shorter than the initial measurement time until the time differential value satisfies the required accuracy. Conditions of measuring the repeated line Ukoto, terminates the measurement when the conditions are met, meeting the precision time differential value of the likewise the standard deviation switched to measurement at a low tube voltage or high tube voltage is obtained become up by irradiating the initial measurement time is shorter than the short time only extend to the primary X-ray repeated rows Ukoto measurement, characterized in that ends the measurement when the conditions are met.
Further, the X-ray fluorescence analyzer of the present invention irradiates a measurement sample with primary X-rays emitted from an X-ray tube at a low tube voltage and a high tube voltage, and the fluorescence X-rays emitted from the measurement sample are detected by a detector. An X-ray fluorescence analyzer that measures light elements and heavy elements contained in the measurement sample at the low and high tube voltages by processing the detection signal and reading it as an energy spectrum. Means for calculating the standard deviation of each element qualitatively measured at the measured initial measurement time, and a minute time shorter than the initial measurement time until a condition satisfying the required accuracy is obtained for the time differential value of the standard deviation of each element. time only measurements in extended high tube voltage by irradiating the primary X-rays or low tube voltage repeated line Ukoto, terminates the measurement when the conditions are met, a lower tube voltage or Means for switching to a measurement at a high tube voltage, and a minute time shorter than the initial measurement time until the conditions satisfying the accuracy required for the time differential value of the standard deviation in the measurement at the low or high tube voltage are satisfied. extended by the time repeating rows Ukoto measured by irradiating the primary X-rays, characterized in that it has a means for ending the measurement when the conditions are met.

As described above, in the present invention, measurement is performed using two conditions of high voltage and low voltage, and qualitative and quantitative determination of light elements and heavy elements contained in a measurement sample are performed by combining these results. Rather than fixing the ratio of high-voltage and low-voltage measurement times to 1: 1, instead of measuring at the set initial measurement time, calculate the standard devote of each element, and calculate By detecting the change over time in the standard deviation of elements with a high tube voltage and a low tube voltage, it is possible to automatically set an optimal measurement time that satisfies the required accuracy. In addition, it is possible to reduce the extra time required for high voltage measurement, which has been performed in the past, and to reduce the time required for setting the voltage condition. As a result , a comprehensively good detection efficiency result can be obtained in a short time .

BEST MODE FOR CARRYING OUT THE INVENTION

  Embodiments of the present invention will be described below. The present invention is not limited thereby.

Figure 1 is determined by monitoring the change with time of the standard deviation of the quantitative value of the result to set a proper measurement time, constituting the first of the present invention to allow high-precision multiple conditions fluorescent X-ray analysis An embodiment is shown.

Thus, measurement is started in step 201 , and in step 202 , the operator sets a predetermined measurement time Ta (second) in advance .

Subsequently, at step 203, Ta / 2 (seconds) is measured at a high voltage as in the conventional case . Subsequently, at step 204, Ta / 2 (seconds) is measured at a low voltage as in the conventional case . By combining these results, the multi-elements contained in the measurement sample 3 are simultaneously qualified (see step 205).

  That is, up to this point, as in the prior art, an arbitrary initial measurement time Ta is set, and automatic qualification after measurement is performed.

Subsequently, among the qualitative elements, first, the standard deviation σ for the heavy element is calculated (see step 206), and the change with time of the standard deviation σ for the heavy element is monitored (detected) . That is, in step 207, the measurement of heavy elements is terminated when the value of Δσ / Δt (time derivative of standard deviation σ for each heavy element) becomes smaller than the arbitrary constant S. In step 207, when the Δσ / Δt value is larger than the arbitrary constant S, only a minute time Δt (seconds) much shorter than Ta / 2 (seconds) is required for recalculation of the standard deviation σ for heavy elements. Extend the high voltage measurement (see step 208) and return to step 206.

After monitoring the time-dependent change of the standard deviation σ for heavy elements, it automatically switches to low voltage measurement, calculates the standard deviation σ for light elements (see step 209), and changes the standard deviation σ for light elements over time. Is monitored (detected) . That is, in step 210, when the value of Δσ / Δt (the time derivative of the standard deviation σ for each light element) is smaller than the arbitrary constant S, the light element measurement is terminated. In step 210, when the Δσ / Δt value is larger than the arbitrary constant S, only a minute time Δt (seconds) much shorter than Ta / 2 (seconds) is required for recalculation of the standard deviation σ for the light element. Extend the low voltage measurement (see step 211 ) and return to step 209.

  In this way, the change with time of the standard deviation σ of the qualitative element is monitored, and the measurement is terminated when the Δσ / Δt value becomes smaller than the arbitrary constant S. First, measurement is performed at a high voltage, and if the condition of Δσ / Δt <S is satisfied, the voltage is switched to a low voltage, and measurement is performed until the condition of Δσ / Δt <S is satisfied as in the case of the high voltage.

  Finally, the element is quantified in step 212, and the measurement ends (see step 213).

  In this embodiment, there is no need to newly set the measurement time as in the prior art. That is, the redoing of the high voltage measurement is eliminated, and the extra time required for the high voltage measurement and the time required for setting the voltage condition, which have been carried out in the past, can be shortened.

  In addition, the optimum measurement time can be automatically set to satisfy the required accuracy. That is, the high voltage measurement and / or the low voltage measurement can be performed by extending the minute time Δt (second) until the condition of Δσ / Δt <S is satisfied.

In the first embodiment , the initial measurement time at the high voltage and the initial measurement time at the low voltage are half of the fixed measurement time Ta (seconds) set by the operator, that is, Ta / 2 ( 2), the measurement is automatically qualified. However, as shown in FIG. 2, the measurement is started in step 201, and a predetermined measurement time Ta set in advance by the operator in step 202 is stored in the memory 10 in advance. Based on the detection efficiency of the light elements and heavy elements, the ratio of the time T _H (seconds) for high voltage measurement and the time T _L (seconds) for low voltage measurement is calculated (step 214), and the ratio is calculated. After measuring with the high voltage measurement time T _H (seconds) and the low voltage measurement time T _L (seconds) obtained automatically in (Steps 203 and 204), automatic qualification is performed, and then the same as in the first embodiment. Step 206 ~ Perform quantification of the elements through 12, it may end the measurement (step 213).

It is a flowchart which shows 1st Embodiment of this invention. It is a flowchart which shows 2nd Embodiment of this invention. It is a flowchart which shows a prior art example. It is a block diagram which shows a fluorescent X-ray analyzer. It is principal part structure explanatory drawing of the said fluorescent-X-ray-analysis apparatus.

Explanation of symbols

1 X-ray tube 2 Primary X-ray 3 Measurement sample 4 X-ray fluorescence 6 Detector 7 Multi-channel analyzer Ta initial measurement time
σ standard deviation
E tube voltage

Claims (2)

The primary X-rays emitted from the X-ray tube at a low tube voltage and a high tube voltage are irradiated onto the measurement sample, the fluorescent X-rays emitted from the measurement sample are detected by the detector, and the signal is passed through the signal processing means to generate energy. A measurement time setting method in a multiple-conditions fluorescent X-ray analysis in which a light element and a heavy element contained in the measurement sample are read at a low tube voltage and a high tube voltage, respectively, by reading as a spectrum. Calculate the standard deviation of each element qualitatively measured at the initial measurement time, and extend it by a minute time shorter than the initial measurement time until the conditions satisfying the required accuracy of the time differential value of the standard deviation of each element. measurement at high tube voltage or low tube voltage and irradiating the primary X-ray repeating rows Ukoto Te, and terminates the measurement when the conditions are met, a lower tube voltage or high Wherein Similarly the rows measured by irradiating the primary X-ray to extend only a short minute time than the initial measurement time to the time differential value becomes a condition to satisfy the required accuracy of the standard deviation switched to the measurement of a tube voltage The measurement time setting method in the multi-condition fluorescent X-ray analysis, wherein the measurement is repeated when the condition is satisfied. A primary X-ray emitted from an X-ray tube at a low tube voltage and a high tube voltage is irradiated onto a measurement sample, and the fluorescent X-ray emitted from the measurement sample is processed as a signal from the detection signal of the detector and read as an energy spectrum. Is a fluorescent X-ray analyzer for measuring light elements and heavy elements contained in the measurement sample at the low tube voltage and the high tube voltage, respectively, and was qualitatively measured by the measurement at the set initial measurement time. The means for calculating the standard deviation of each element and the primary X-rays are irradiated by extending by a minute time shorter than the initial measurement time until the conditions satisfying the required accuracy of the time differential values of the standard deviation of each element. measurements at high tube voltage or low tube voltage Te repeating rows Ukoto, terminates the measurement when the conditions are met, and means for switching the measurement of a low tube voltage or high tube voltage, In the measurement at a low tube voltage or a high tube voltage, the primary X-ray is irradiated by extending by a minute time shorter than the initial measurement time until a condition satisfying the required accuracy of the time differential value of the standard deviation is obtained. repeatedly rows Ukoto the measurement, fluorescent X-ray analysis apparatus characterized by and a means for ending the measurement when the conditions are met.

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