JPH1130586A - Emission spectrometric analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the analysis accuracy for every measurement element, by erecting, between a light-emitting part and a light-condensing part, a plate body having a plurality of windows correspondingly to an optimum emission position for the measurement element. SOLUTION: The plate body 5 having a plurality of windows 51-53 is set between a discharge column (light-emitting part) 3 formed between a sample 1 and a counter electrode 2 and a condenser lens (light-condensing part) 4. An opening of each window 51-53 of the plate body 5 has a size of 1×1.5 μm and is set at a height corresponding to a temperature band 31-33 of the discharge column 3, 10,000K, 8000K, 5000K. The plate body 5 enables alkali metals such as Na, K, etc., to be measured accurately at an optimum measurement position of the 5000K band, similarly, P, S, Mn, etc., at the 8000K band and the other metallic elements at the 10,000K band. The plate body 5 can be provided with a single window, in place of the plurality of windows 51-53, which is moved up and down via a rod or the like by a motor equipped with a decelerator. The same effect and operation can be obtained in this case as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to atomic emission spectroscopy using spark or arc discharge.
scopy, AES).

[0002]

2. Description of the Related Art In an emission spectrometer, a discharge column (light emitting portion) c and a spectroscope (spectral portion) d formed between a sample a and a counter electrode b are conventionally provided as shown in FIG. A condensing lens (condensing portion) e and an entrance slit f are arranged between the two, and discharge light in a band corresponding to a slit width at a height position corresponding to one point of the discharge column c is extracted by the entrance slit f. It was spectroscopically measured. In FIG. 7, g is a detector, h
Is an amplifier, and i is a recorder.

[0003]

By the way, the temperature distribution in the height direction of the discharge column c is highest near the sample surface (+), and decreases as it goes to the counter electrode side (-). Surface temperature, the temperature difference is 3,000 ℃ ～ 5,0
It has been confirmed that the temperature reaches 00 ° C. That is, a temperature distribution corresponding to an ion beam around 10,000 K near the sample surface, a high energy atom beam around 8,000 K, and a low energy atom beam around 5,000 K near the counter electrode surface is observed.

Therefore, the maximum S / N ratio depends on the type of element.
In the conventional emission spectrometer described above, the measurement position is fixed to a predetermined height region by the entrance slit f which is arranged in a fixed state, despite the fact that the light emission site where the light emission portion is obtained is different. Therefore, improvement in analysis accuracy for each measurement element could not be achieved.

The temperature of the outer periphery of the cross section of the discharge column is low,
A band spectrum of the ambient air gas and the counter electrode vapor appears,
It has been confirmed that this acts as noise.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an emission spectrometer that improves the analysis accuracy for each measurement element.

[0007]

According to the present invention, means for solving the above-mentioned problems are constituted as follows. The invention according to claim 1 is characterized in that a plate body having a plurality of windows corresponding to an optimum light emitting position for a measurement element is provided between the light emitting unit and the light collecting unit.

According to the second aspect of the present invention, instead of the plate having a plurality of windows in the first aspect of the present invention,
It is characterized in that a movable plate having a single window is provided.

According to a third aspect of the present invention, in place of the plate having a plurality of windows in the first aspect of the present invention,
It is characterized in that a mask disk having a plurality of windows formed on a rotationally driven disk is erected.

[0010]

FIG. 1 is a schematic diagram showing an embodiment of an emission spectrometer (hereinafter referred to as an apparatus) of the present invention.
Reference numeral 1 denotes a metal solid sample (hereinafter, referred to as a sample), 2 denotes a counter electrode, 3 denotes a discharge column (light emitting portion) formed between the sample 1 and the counter electrode 2, and 4 denotes a condensing lens (condensing portion). , 5 are discharge columns 3
And a plate provided between the lens and the condenser lens 4, and has three windows 51, 52, and 53. Reference numeral 7 denotes a spectroscope (including an entrance slit), and reference numeral 8 denotes a detector composed of a photomultiplier (photomultiplier). Although not shown, the detector 8 is connected to an amplifier and a recorder.

Each of the windows 51, 52, 53 formed on the plate 5 has an opening dimension of about 1.times.1.5 .mu.m.
K, 8,000K, and 5,000K are set at the height portions corresponding to the respective temperature bands. With such a plate 5, alkali metals such as Na and K can be used in the 5,000K band, and P, S and Mn can be used in the 8,000 band.
The K band and other metal elements can be accurately detected at optimal measurement positions in the 10,000 K band.

Incidentally, the photocathode (8 × 24 mm) of the detector 8 composed of a photomultiplier has a sufficient light receiving area, and an exit slit (not shown) provided in front of the detector 8 is more than usual. It may be set slightly longer in the spark optical axis direction.

Although the plate 5 having the plurality of windows 51, 52, 53 is provided in a fixed state, a movable plate having a single window may be provided. In this case, although illustration is omitted, for example, if a guide rail for guiding the plate body is provided on both sides of the plate body, and the plate body is moved up and down via a rod or the like by a motor with a reduction gear, Good.

FIG. 2 shows the overall configuration of a different embodiment of the apparatus, and FIG. 3 shows the main configuration thereof. In this case, a rotatably driven mask board 15 is provided between the condenser lens 4 and the protection plate 11. Has been established. Here, 71 is a diffraction grating, 81 to 83 are first, second, and third detectors, 9 is an exit slit, and 12 is a sample 1
And a light emitting device for supplying power to the counter electrode 2, and 13 is a detection circuit.

The above-mentioned mask board 15 is, as shown in FIG.
A disk 152 driven to rotate by a motor (not shown) around the axis 151 has different distances from the axis 151.
Windows 153, 154, 155, 156 are provided with phases different by 90 °, the windows 153 and 154 are used for photometry on the sample side, and the windows 155 and 155 are provided.
6 is for central photometry, and the windows 153 to 156 have slightly different shapes and sizes, but have a width of 30 to 50 mμ and a height of 100 to 100 μm.
It is about 1000 mμ.

The measuring method is as shown in FIG.
Photometry is performed every second for alternately windows (153 and 154) and (155 and 156) for a total of 20 seconds. The reason why the photometry is performed alternately is that there are components that evaporate well in the early stage of discharge and components that evaporate well in the latter stage due to the components in the sample. It should be noted that the measurement section after the detector 8 is controlled so that the central photometry spectrum is not measured during the sample side photometry and the sample side photometry spectrum is not measured during the central photometry.

According to the measuring method as described above, the windows 153 and 1
The discharge light near the sample surface is collected by the condenser lens 4 by 54, and the central part of the discharge column 3 is collected by the condenser lens 4 by the windows 155 and 156. Since the discharge light can be introduced from the optimum measurement position and the outer periphery of the cross section of the discharge column, which causes noise, is not introduced, the S / N of the spectrum intensity corresponding to the target element is increased.
Is remarkably improved, and the measured value corresponds to the content of the target element, so that the reproducibility of the analysis value is remarkably improved.

FIG. 6 shows an essential structure of an apparatus using such a mask board 15, for example.
The subsequent spectroscopic unit (spectroscope 7) is of a vacuum type, and an argon gas (Ar) is externally introduced into the discharge chamber.
Since the evaporant from the sample 1 is easily filled by the discharge,
A protective plate 11 is provided so that the condenser lens 4 is not contaminated by the evaporant. A mask board 15 is disposed between the protective plate 11 and the condenser lens 4 and is mounted on, for example, a step motor (not shown). ) And the like.

[0019]

As described above, according to the emission spectrometer of the present invention, a plate body having a plurality of windows corresponding to an optimum light emitting position for a measurement element is provided between a light emitting portion and a light collecting portion. The elements whose intensity is likely to change with time at normal positions, such as P and S, and elements whose emission positions are significantly different from other elements, such as Na and K, are measured at the optimum detection limit. be able to.

The same operation and effect can be obtained by a movable plate having a single window.

Alternatively, a mask disk having a plurality of windows formed on a rotating disk may be provided. In this case, a window for collecting discharge light near the sample surface and a discharge light from the center of the discharge column are collected. By providing the window, noise is removed, the S / N of the spectrum intensity corresponding to the target element is remarkably improved, and high analysis accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of an emission spectrometer according to the present invention.

FIG. 2 is an overall configuration diagram showing a different embodiment of the emission spectrometer.

FIG. 3 is a configuration diagram of the main part.

FIG. 4 is a plan view of the mask board.

FIG. 5 is a diagram showing the photometric schedule.

FIG. 6 is a sectional view showing the structure of the relevant part.

FIG. 7 is a schematic configuration diagram of a conventional emission spectrometer.

[Explanation of symbols]

3 ... Light-emitting part, 4 ... Condensing part, 5 ... Plate, 51, 52, 53, 153
, 154, 155, 156 ... window, 15 ... mask board, 152 ... disk.

Claims (3)

[Claims] 1. An emission spectroscopy apparatus characterized by comprising a plate having a plurality of windows corresponding to an optimum light emission position for a measurement element between a light emission part and a light collection part. 2. The emission spectrometer according to claim 1, wherein a movable plate having a single window is provided instead of the plate having a plurality of windows. 3. The apparatus according to claim 1, wherein a mask disk having a plurality of windows formed on a rotatably driven disk is provided in place of the plate having a plurality of windows. Emission spectrometer.