JP5062094B2 - Luminescence analyzer - Google Patents

Description

  The present invention relates to an emission analyzer that excites a sample by so-called spark discharge such as spark discharge or arc discharge and performs spectroscopic measurement of the emitted light.

  In an emission spectrometer, generally, a solid sample that is a metal or a nonmetal is energized by spark discharge or arc discharge to evaporate and evaporate the sample. Then, the emitted light is introduced into the spectroscope, a spectral line having a wavelength unique to each element is extracted, the intensity is detected, and the sample is identified and the impurities in the sample are quantified based on the detection result. . Such an emission analyzer is capable of highly accurate analysis, and is therefore widely used, for example, to analyze the composition of a produced metal body in a production factory for ferrous materials and non-ferrous metal materials.

  Of the discharges used in such an emission analyzer, the spark discharge can obtain a sharp peak discharge energy intensity in a short time, whereas the arc discharge takes a relatively long time (compared to the spark discharge). It has the feature that stable discharge energy intensity can be obtained. Which discharge is suitable in terms of analytical sensitivity depends on the element. Therefore, in order to analyze various elements with high sensitivity, a discharge method in which a spark discharge and an arc discharge are simultaneously performed by one discharge is conventionally known (see, for example, Patent Document 1).

  FIG. 4 shows an example of a waveform (hereinafter referred to as “discharge profile waveform”) showing a temporal change in discharge intensity in such simultaneous discharge. In this discharge profile waveform, the sharp peak waveform in the first half is due to spark discharge, and the gentle waveform in the second half is due to arc discharge.

  The shape of the discharge profile waveform as described above, that is, the temporal change in the discharge intensity depends on discharge condition parameters such as applied voltage, application time, and application timing when each discharge is generated. In addition, the shape of the discharge profile waveform that is appropriate differs depending on the type and content ratio of elements contained in the sample to be analyzed, the purpose of analysis, and the like. Therefore, conventionally, a user who uses an emission analysis apparatus adjusts the shape of the discharge profile waveform to a desired state by appropriately setting the discharge condition parameters according to the sample to be analyzed and the analysis purpose. Yes. In such adjustment, it is confirmed whether or not a desired discharge profile waveform can be obtained with the set discharge condition parameters by observing the discharge current using a waveform observation device such as an oscilloscope.

  However, in order to observe the discharge profile waveform, there is a problem that it is troublesome and troublesome to connect the waveform observation device to the emission analysis device one by one. Further, depending on the operation status of the emission analyzer, there are cases where it is difficult to connect the waveform observation apparatus, and in such a case, there is a problem that the actual shape of the discharge profile waveform cannot be confirmed.

Japanese Patent Publication No.6-100546

  The problem as described above can be solved by incorporating hardware corresponding to the waveform observation apparatus into the emission analyzer, which may cause a significant cost increase of the emission analyzer. In addition, it is difficult to deal with an existing emission analyzer that the user already has.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to provide firmware for an emission analyzer without using or adding special hardware including a waveform observation device. Another object of the present invention is to provide an emission analyzer capable of obtaining a discharge profile waveform by changing software or software for data processing.

The present invention, which has been made to solve the above-mentioned problems, is an emission analysis apparatus for spectroscopically measuring emission light emitted from a sample in response to a discharge, wherein the emission analysis is capable of setting a temporal intensity change of the discharge. In the device
a) a measurement period setting means for setting a measurement start timing for starting intensity measurement of emitted light for one discharge and a measurement end timing for ending the intensity measurement;
b) while sequentially changing the measurement period set by the measurement period setting means, by performing an intensity measurement of the emission light from the predetermined sample for the discharge is performed at least one discharge for the same measurement period, different A measurement execution means for acquiring emission light intensity measurement results for a plurality of discharges over a plurality of measurement periods ;
c) Waveform creation processing means for creating and rendering a discharge profile waveform corresponding to the temporal intensity change of the discharge, using the emission light intensity measurement results for different measurement periods acquired by the measurement execution means;
It is characterized by having.

  In the emission analysis apparatus according to the present invention, instead of observing a discharge current or the like in a discharge section that causes discharge, a detection signal (light) generated in a detector by light emitted from the sample when discharge is performed on the predetermined sample. Current signal) is observed, and a discharge profile waveform is created based on this signal. For each discharge, a detection signal reflecting the discharge intensity in the measurement period set by the measurement period setting means is obtained. Therefore, by setting a plurality of measurement periods so as to cover the discharge period from the start to the end of one discharge, a discrete detection signal corresponding to the temporal change in the discharge intensity can be obtained. A discharge profile waveform can be obtained by interpolating between two detection signals adjacent to each other by an appropriate method.

  If the time intervals of the discrete detection signals are too wide, it is difficult to capture a rapid change in discharge intensity with respect to one discharge. Therefore, in order to obtain a discharge profile waveform that reflects a change in actual discharge intensity, the above-mentioned amount is sufficient to obtain a sufficient number of measurement points in the discharge period from the start to the end of one discharge. It is desirable to set the measurement period sufficiently short.

  In general, in emission analysis, the variation in the intensity of light emission from the sample with respect to the discharge is relatively large, and even in normal measurement, multiple discharges are performed on the same location on the sample, and the measurement results obtained for each discharge Variation is reduced by performing processing such as averaging. Therefore, as a preferable aspect of the emission analyzer according to the present invention, the measurement execution unit performs discharge and emission light intensity measurement a plurality of times in the same measurement period, and the waveform creation processing unit includes the same It may be configured to execute a process of reducing variations in values using a plurality of emission light intensity measurement results for the measurement period.

  Here, the process for reducing the variation can be, for example, averaging a plurality of data, discarding extremely small or excessive data, or a combination thereof. Thereby, the reliability of the measurement result in each measurement period can be improved, and as a result, the accuracy of the discharge profile waveform created based on this can be improved.

  The emission analysis apparatus according to the present invention further comprises wavelength specifying means for specifying the wavelength of the emitted light for creating the discharge profile waveform, and the waveform creating processing means is the emitted light having the wavelength specified by the wavelength specifying means. It can be set as the structure which produces a discharge profile waveform using an intensity | strength measurement result.

  For example, when the configuration is a multi-wavelength simultaneous analysis using a Baschen-Lunge-type spectrometer and a plurality of detectors (photomultiplier tubes, etc.), the measurement result obtained with a specific detector is a single wavelength measurement. It is a result. Therefore, by selectively using the detection result obtained by the detector corresponding to the wavelength designated by the user using the wavelength designation means, a discharge profile waveform at the designated wavelength can be easily created. Of course, since a plurality of detectors can measure different single-wavelength lights at the same time, discharge profile waveforms at a plurality of designated wavelengths can be created.

  The measurement execution means in the emission analyzer according to the present invention can be realized by using the hardware for performing normal emission analysis as it is and changing only the firmware and software that define the control procedure. The waveform creation means can also be realized by data processing software that operates on a computer. Therefore, according to the emission analyzer according to the present invention, it is not necessary to use another measuring device such as an oscilloscope to confirm the discharge profile waveform, and special hardware is also added to the device. There is no need to add a discharge profile waveform drawing function by changing or adding firmware or software. Therefore, an increase in cost for adding such functions can be suppressed, and addition of functions to existing devices already owned by the user can be performed relatively easily.

  Furthermore, in the emission analysis apparatus according to the present invention, a single-wavelength discharge profile waveform after the emission light is dispersed can be obtained, so that it is possible to improve accuracy during the work of adjusting the temporal change in discharge intensity. It can contribute to improving the accuracy of emission analysis.

  An embodiment of an emission analyzer according to the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a main part of an emission analyzer according to the present embodiment.

  The discharge unit 1 can generate a spark discharge and an arc discharge at the same time, and discharges the sample 3 according to the discharge conditions (applied voltage, voltage application time, voltage application timing, etc.) set by the discharge condition setting unit 2. Execute. The sample 3 is excited to emit light by this discharge, and the emitted light is introduced into the spectroscope 4 and wavelength-dispersed. The spectroscope 4 has a Paschen-Lunge type configuration, and includes an entrance slit, a concave diffraction grating, and a plurality of exit slits arranged on a Roland circle. The plurality of exit slits are arranged at positions where wavelength light unique to a specific element of the chromatic dispersion light (here, wavelengths λ1, λ2, and λ3) can pass. Single-wavelength light extracted from each exit slit of the spectroscope 4 is introduced into separate photodetectors 5a, 5b, and 5c. The photodetectors 5a, 5b, and 5c are typically photomultiplier tubes, and generate a photocurrent corresponding to the intensity of incident light.

  The integrators 6a, 6b, and 6c provided for the photodetectors 5a, 5b, and 5c integrate the photocurrent generated at each discharge. The control unit 15 sets the integration start timing and integration end timing of each integrator 6a, 6b, 6c for one discharge. The integration start and end timings in the integrators 6a, 6b, and 6c correspond to the measurement start timing and the measurement end timing in the present invention. One of the integrated values of the photocurrents by the integrators 6a, 6b, and 6c is selected by the switching unit 7, converted into digital data by the A / D converter 8, and input to the data processing unit 10.

  The data processing unit 10 includes a discharge profile creation unit 11 as a functional block characteristic of the present invention. The discharge profile creation unit 11 includes a data storage unit 12, an averaging calculation unit 13, an interpolation processing unit 14, and the like. The data processing unit 10 and the control unit 15 for controlling the luminescence analysis operation can be embodied, for example, with the personal computer 20 as a center, and an input unit that allows a user to set discharge condition parameters and various parameters described later. 21 and a display unit 22 for displaying a discharge profile waveform and the like.

  Hereinafter, the procedure and operation when performing the discharge profile waveform generation operation in the emission spectrometer of the present embodiment will be described. At this time, the user inputs in advance from the input unit 21 condition parameters such as the number of discharge repetitions n, the measurement period m for each discharge, and the designated wavelength λ (selected from λ1, λ2, or λ3).

  When the operation is started, the discharge unit 1 repeats discharge according to the discharge condition parameter set in the discharge condition setting unit 2 n times under the instruction of the control unit 15. When the spark discharge and the arc discharge are performed simultaneously, the temporal change in the discharge intensity in one discharge is as shown in FIG. In addition, as an initial setting, the control unit 15 sets the integrators 6a to 6c so that the discharge start time t = 0 is set as the integration start timing and t = m is set as the integration end timing. Here, considering the case where the designated wavelength is only λ1, only the integrator 6a corresponding to the wavelength λ1 may be used.

  In the case of n repeated discharges from the first time to the nth time, the photocurrent generated in the photodetector 5a is integrated in the time range indicated by hatching in FIG. 2A for one discharge. It is integrated by the device 6a. The integral value is digitized by the A / D converter 8 for each discharge (this data is referred to as integral data) and temporarily stored in the data storage unit 12. When the n-th discharge is completed and n pieces of integral data are accumulated in the data storage unit 12, the averaging calculation unit 13 calculates an average value of the n pieces of integral data, and the average value data is expressed as P (1 ) In the data storage unit 12. It should be noted that the accuracy of the average value data may be reduced if there is extremely excessive data or excessive data due to some abnormality. Also good.

  On the other hand, when the n-th discharge is completed, the control unit 15 changes the settings of the integrators 6a to 6c so that t = m is an integration start timing and t = 2m is an integration end timing. Then, the discharge unit 1 is controlled to repeat n times of discharge. In the case of n repeated discharges from the (n + 1) th time to the 2nth time, a photocurrent generated in the photodetector 5a is generated in a time range indicated by hatching in FIG. 2 (b) with respect to one discharge. Integration is performed by the integrator 6a. The integrated value is digitized by the A / D converter 8 for each discharge and temporarily stored in the data storage unit 12. Then, as in the case of the first to n-th repeated discharges, the average value of the integral data acquired for each of the n discharges is calculated, and the data storage unit 12 uses the average value data as P (2). To remember.

  Thus, integration data for each discharge is collected while shifting the integration start timing and integration end timing every n repeated discharges, that is, setting different measurement periods, and when n pieces of integration data are collected, the average value data is collected. Is repeated until the end of discharge (see FIGS. 2C and 2D). As a result, average value data P (1) to P (k) corresponding to the time range divided for each measurement period m is collected over the entire discharge period from the start of discharge to the end of discharge.

  Assuming that the average value data is located at an intermediate position in each measurement period m, the average value data P (1) to P (k) are plotted as shown in FIG. This is discrete data along the discharge profile waveform indicating the temporal change of the discharge intensity at the designated wavelength λ1. A time interval between two pieces of average value data adjacent in time is m. Therefore, the shorter the measurement period m, the more accurately the rapid temporal change of the discharge intensity is reflected. Further, in order to create a continuous waveform based on discrete data on the time axis obtained in this way, the interpolation processing unit 14 performs data interpolation processing. In this data interpolation process, it is preferable to execute a high-order data interpolation process using not only two points of data before and after the time but also a plurality of points of data before and after. Since the curved waveform as shown in FIG. 3B is reproduced by such data interpolation processing, this is output to the display unit 22 as a discharge profile waveform.

  When a plurality of wavelengths, for example, λ1 and λ2 are specified, a discharge profile waveform is created in the same manner as described above based on the integration value obtained by the integrator 6b in addition to the integration value obtained by the integrator 6a. Output to the display unit 22.

  As described above, in the emission analyzer of the present embodiment, the discharge profile waveform at the specified wavelength can be created and drawn using the measurement result of the emission intensity. Therefore, it is possible to adjust the discharge condition parameters so that the desired waveform shape is obtained while checking the discharge profile waveform.

  The above-described embodiment is an example of the present invention, and it is a matter of course that modifications, corrections, and additions may be appropriately made within the scope of the present invention, and included in the scope of the claims of the present application.

1 is a schematic configuration diagram of an emission analyzer that is one embodiment of the present invention. Explanatory drawing of the discharge profile creation process in the emission spectrometer of a present Example. Explanatory drawing of the discharge profile creation process in the emission spectrometer of a present Example. The figure which shows an example of the time change of discharge intensity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Discharge part 2 ... Discharge condition setting part 3 ... Sample 4 ... Spectroscope 5a, 5b, 5c ... Photo detector 6a, 6b, 6c ... Integrator 7 ... Switching part 8 ... A / D converter 10 ... Data processing part DESCRIPTION OF SYMBOLS 11 ... Discharge profile creation part 12 ... Data storage part 13 ... Averaging calculation part 14 ... Interpolation processing part 15 ... Control part 20 ... Personal computer 21 ... Input part 22 ... Display part

Claims (3)

In an emission analysis apparatus for spectroscopically measuring emitted light emitted from a sample in response to a discharge, the emission analysis apparatus capable of setting a temporal intensity change of the discharge,
a) a measurement period setting means for setting a measurement start timing for starting intensity measurement of emitted light for one discharge and a measurement end timing for ending the intensity measurement;
b) while sequentially changing the measurement period set by the measurement period setting means, by performing an intensity measurement of the emission light from the predetermined sample for the discharge is performed at least one discharge for the same measurement period, different A measurement execution means for acquiring emission light intensity measurement results for a plurality of discharges over a plurality of measurement periods ;
c) Waveform creation processing means for creating and rendering a discharge profile waveform corresponding to the temporal intensity change of the discharge, using the emission light intensity measurement results for different measurement periods acquired by the measurement execution means;
An emission analysis apparatus comprising:
The emission analyzer according to claim 1,
The measurement execution means performs a plurality of discharge and emission light intensity measurements for the same measurement period,
The waveform generation processing means executes a process for reducing variations in values using a plurality of emission light intensity measurement results for the same measurement period. The emission analyzer according to claim 1 or 2,
The apparatus further comprises wavelength designating means for designating the wavelength of the emitted light for creating the discharge profile waveform, and the waveform creation processing means generates the discharge profile waveform using the emission light intensity measurement result of the wavelength designated by the wavelength designating means. An emission analyzer characterized in that it is created.

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