JPS58171650A - Method and apparatus for quantitative analysis using kerr's spectroscopic method - Google Patents

Abstract

PURPOSE:To enable accurate quantitative analysis by using one measuring system and to reduce cost, by arranging the first system filled with the substance to be measured and the second system filled with a reference substance in series. CONSTITUTION:A measuring apparatus has a cell A as the first system to be filled with the substance to be measured and a cell B as the second system filled with a reference substance. For example, gaseous silane SiH4 as the substance to be measured, and carbon monooxide CO as the reference substance are used. In those cases, the peak (A) of silane SiH4 exists at 602.2nm wavelength, and the peak (B) of carbon monooxide CO exists at 600.4nm wavelength. The concn. of the substance to be measured can be obtained by measuring the intensity ratio of both peaks (A) and (B), permitting exact quantitative analysis at a reduced cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a quantitative analysis method and apparatus using Kerse spectroscopy.

Kaas spectroscopy is a type of nonlinear Raman spectroscopy that has progressed with the development of high-power radars and dirades, and has a detection sensitivity that is about 10-5 times that of ordinary Raman spectroscopy. Therefore, there are many expectations regarding its application.

The principle of this Kerse spectroscopy can be briefly explained as follows. As shown in Figure 1, the substance (Raman active substance) R
M has an excitation Radhe beam with a frequency ωl, and the same frequency as the Stokes beam of the object [RM (Stokes frequency) ω, (=ω1−
When irradiated with a laser beam of Ω, where Ω is the natural frequency of the molecules of the material RM, the anti-Stokes light of the material RM (
The vibration frequency ω3=ω1+Ω) is generated resonantly and extremely strongly in the form of a beam. This phenomenon can be viewed as a four-photon process, as shown in the energy diagram in Figure 2. Also, the intensity I3 of the anti-Stokes light at this time is l3oc112・Iyuki・N2 ・・・・・・・・・
...(1) (where N is the density of the material RM, 1 is the intensity of the Rede light with the frequency ωX, and I is the intensity of the laser light with the frequency ω) - Therefore, the above anti-Stokes light Strength of ■
3, the concentration of the substance RM can be detected. Kerse spectroscopy is based on the above principle, and when the intensity of the anti-Stokes light is detected, the concentration of the substance to be measured is determined.

By the way, the light detected by Kerss spectroscopy actually fluctuates greatly depending on the intensity of the excitation Radhe light and the conditions of the optical system. The signal from a reference cell containing a known reference substance was used as a standard to correct the intensity of the belief from the system being measured, and the concentration was measured based on this. Figure 1 shows such conventional Kerse spectroscopy. This shows a quantitative analysis device using the method, in which cell A is filled with a substance to be measured, and cell B is filled with a reference substance at a predetermined concentration. The excitation Rade light with a frequency of 0 is reflected by a mirror 1 and guided to a beam splitter 2, and the Rade light with a frequency of ω is applied to the beam splitter 2. The beam sgritter 2 combines the excitation Radhe light with a frequency of ω1 and the Rade light with a frequency of ω, divides this combined light into two parts, and sends one of them to the lens 4 and the cell A.
, lens 5, prism 6 to spectroscope 7, and the other side is connected to mirror 3, lens 8, cell B lens 9, prism 10.
is added to the spectrometer 11 via the.

The spectrometers 7 and 11 are each provided with a detector 7m and l1m, and the intensity of the light applied to the spectrometers 7 and 11 is detected as an electrical signal.

However, the conventional method described above requires two signal detection systems: a first signal detection system including the spectrometer 7 and the detector 71, and a second signal detection system including the spectrometer 11 and the detector l1m.
Furthermore, since the optical axis adjustment had to be performed in two systems, the cost was high and the adjustment operation was time-consuming.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a quantitative analysis method and apparatus using Kerse spectroscopy, which has a simple configuration and reduces the number of adjustment points by half.

Therefore, in this invention, together with the excitation Raded light of frequency ω1, the Raded light of frequency ω applied to the substance to be measured has a wide linewidth (broadband) and is used as a base. A cell and a second cell filled with a reference substance are arranged in series with respect to the input laser beam, and the Rade light that has passed through the first cell and the second cell is simultaneously detected in different channels for each wavelength. The concentration of the substance to be measured is detected from the intensity ratio of the signal output corresponding to the substance to be measured and the signal output corresponding to the reference substance generated in different channels of the multi-channel detector. This enables accurate concentration detection with a single detection system.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 shows an embodiment of the present invention, and parts that perform the same functions as those of the device shown in FIG. 3 are given the same reference numerals for convenience of explanation. That is, cell B is a cell for filling with a substance to be measured, and cell B is a cell for filling with a reference substance. In this embodiment, a YAG laser beam (wavelength: 532 nm) YAG is used as the excitation radar beam, and a broadband die radar beam Dya is used as another radar beam added to the measurement system together with the excitation radar beam YAG. The YAG radar light is reflected by the YAG i mirror 12 and guided to the dichroic mirror 13, and the dichroic mirror Dys is applied to the dichroic mirror 13 from a direction perpendicular to the YAG radar light YAG. The dichroic mirror 13 reflects the YAG laser beam YAG and the dichroic mirror 13 reflects the YAG laser beam YAG.
It transmits YAG laser light YAG,! :
/Eraser light and Φ are synthesized by this dichroic mirror 13. This combined light is applied to the spectrometer 19 via the lens 14, cell A, lens 15, lens 16, cell B, lens 17, and prism 18, and is detected by the detector 19m. Here, the detector 191L is the spectrometer 1
A so-called multi-channel detector is used that simultaneously detects the light received by the detector 9 for each wavelength on different channels. In addition, lenses 14, 15, 16
17 is a lens for converging or refocusing the Raded light, which is not necessarily necessary as long as the convergence of the Raded light can be maintained.

FIG. 5 shows an example of measurement using the apparatus shown in FIG. This graph shows wavelength on the horizontal axis and signal strength on the vertical axis. In this measurement example, the measured substance is silane 5SU4 (Raman wave number 21901-1), and the reference substance is carbon monoxide CQ (Raman wave number 214351-').
for σiΣ′. In the graph shown in Figure 5, the peak (
4) is based on silane gas 5IH4 and has a wavelength of 602.
Appears at a position of 2 nm. The peak (B) is due to -carbon oxide CO and appears at a wavelength of 600.4 nm. The concentration of the substance to be measured (in this case, silane 5Sa4) can be determined from the intensity ratio of the peaks (A) and (B). Note that the absolute concentration is calibrated by measuring the ratio with a reference substance using a substance to be measured whose concentration is known and measured by another method, and using this ratio as a reference.

Figure 6 shows silane gas 81! caused by plasma discharge! (.

This figure shows an embodiment in which the present invention is applied to an apparatus for measuring changes in the concentration of. Plasma chamber-2
0 is filled with silane gas SiH4 via a valve 21. Then, the absolute pressure of the 5 in 4 silane at this time is measured by the pressure gauge 22. In addition, electrode 23m, 23bF
i7” electrode for plasma, valve 24 is plasma chamber 20
Al with a valve for gas discharge inside. Mata reference cell 25
is filled with carbon monoxide CO from the FiCo membrane 26 via valves 27 and 28.

In this forest condition, laser light (combination of YAG Raded light YAG and Dyraded light DYC) &1 + V2 is combined with lens 29
'''C converges and irradiates inside the plasma chamber/appetizer-2Q,
The light that has passed through the plasma chamber 20 is refocused by the lens 30 and irradiated onto the reference cell 25. Of the light that has passed through the reference cell 25 and is converged by the lens 31, those related to anti-Stokes light are dichroic and Cumiller 3.
2, it is separated from the Rade light 1+V2 and guided to a spectrometer (not shown). The spectrometer measures the received light intensity for each wavelength using the i-multichannel, thereby obtaining a graph as shown in FIG.

The measured substance (81H4) and the reference substance (Co) at this time
The peak ratio of is the reference for the following silane gas concentration measurement.

Next, a discharge is generated between the electrodes 23m and 23b of the plasma chamber 20, and the peak ratio of the measured substance (SiH4) and the reference substance (CO) at this time is measured. by the way! The silane gas concentration in the plasma chamber changes due to discharge, but the Goss monoxide concentration in the reference cell does not change. Therefore, from the above peak ratio, the change in silane gas concentration can be calculated as
J can be determined.

The above example shows a case in which the present invention is applied to the measurement of changes in silane gas concentration during plasma discharge, but this is just one example, and the present invention can be applied to the field of quantitative analysis. You should understand.

For example, the present invention is also effective for quantitative analysis of the combustion process within an engine.

In addition, in the embodiments shown in FIGS. 4 and 6,
Although a measured substance system (cell A or plasma chamber 20) and a reference substance system (cell Bt or reference cell 25) are arranged for the manual LED light, the reverse arrangement may be used. That is, the input laser beam may be configured to first pass through the reference material system and then input into the measured material system.

Further, as the reference material used in this invention, any material can be used as long as it has a Raman frequency sufficiently close to that of the substance to be measured (that can be covered by other Rade light added together with the excitation laser light).

As explained above, according to the present invention, accurate quantitative analysis is possible with a single measurement system, and the cost can be reduced, and the number of adjustment points is reduced, making the operation easier.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams explaining the principle of Kerse spectroscopy used in this invention, Figure 3 is a diagram explaining details of this invention,
FIG. 4 is a diagram for explaining one embodiment of the invention, FIG. 5 is a graph showing a measurement example according to the invention, and FIG. 6 is a diagram showing another embodiment of the invention. 1.3.12...Mirror, 2...Beam currant, tar, 7.11.19...Spectroscope, 13.32...Dichroic mirror, 20...Plasma chatuno=-
125...Reference cell, A, B...Cell. Procedural amendment layer Commissioner of the Patent Office 1. Indication of the matter Patent Application No. 54627 of 1982 2. Name of the invention Quantitative analysis method and apparatus using Kerse spectroscopy 3. Relationship with the person making the amendment Patent application Person (123) Komatsu Manufacturing Co., Ltd. 4, Agent (104) 2-11-2, Ginza, Chuo-ku, Tokyo Claims section of the specification and detailed explanation of the invention 6, Contents of amendments (11 The claims in the specification of the present application are corrected as shown in the attached sheet. (2) Specification of the present application, page 3, line 3, rlo-”J
(3) Correct "active substance" in line 7 of page 3 to "active substance". (4) In the same page, page 4, line 15, "Figure 1" is corrected to "Figure 3." (Correct "beam splitter" in lines 19 and 20 of sls page 4 and line 1 of page 5 to "dichroic mirror." 2 minutes L-r
Correct it to ``Divide Jor into two with beam splitter 2'.'' (7) Similarly, in the 6th page, line m2, "the line width" is corrected to "the line width of the oscillation frequency". (8) IWI, on page 6, line 7, ``Cast'' is corrected to ``Arrangement.'' (91 same, #I6 page, line 14, "nakenga" is corrected to "na detection ga". (lO) same, @9be19m12th line rDYc JerD
ye JK correction. (11) Same, page 9, line 20, “in the channel” t
Correct to "with channel detector." (12) Same, page 11! ! Change "2...beam splinter" in line 20 to "2...dichroic mirror,
2'...beam splitter". (13) Figures 1 and 3 of the drawings of this application are each revised in A9 of the attached sheet. Claim 0) A second system filled with a reference substance is arranged in series with a ml system filled with a substance to be measured, and a first system for excitation.
and a second laser beam that includes both the Stokes frequencies of the substance to be measured and the reference material are added to the wJ1 second system, and the first system W
The laser light that has completely passed through the thread j2 is detected by a multi-channel detector, and I is generated in each different channel of the multi-channel detector.
A quantitative analysis method using Kerse spectroscopy, in which the concentration of the substance to be measured is detected from the intensity ratio of the signal output corresponding to the substance to be measured and the signal output corresponding to the reference substance. (2) A quantitative analysis method using Kerse spectroscopy according to claim 1, wherein the substance to be measured is silane/gas tfct nitrogen silane gas, and the reference substance is carbon monoxide. A first means for emitting a laser beam of 1, and a Stokes vibration number of the measured substance and the reference substance: i7
a second means for oscillating the laser beam of the body 2, which includes both;
means @3 for combining the laser light of [se@] and the laser light of group 2 to form an input laser light; a first chamber filled with the substance to be measured; a second chamber disposed directly in the first chamber and filled with the reference substance at a predetermined concentration; and a second chamber that transmits the laser light that has passed through the first chamber and the second chamber to different channels for each wavelength. a multi-channel detector e f xuan e xiao for detection, and a signal output corresponding to the substance to be measured and a signal output corresponding to the reference substance occurring in different channels of the multi-channel detector; A quantitative analysis device t using Kaas spectroscopy, which detects the #I degree of the substance to be measured from the ratio.

Claims (3)

[Claims] (1) A second system filled with a reference substance is arranged in series with a first system filled with a substance to be measured, and a first laser beam for excitation is used to stimulate the substance to be measured and the reference substance. In addition to the first and second systems together with a second laser beam that both includes a Stokes frequency, the laser beam that has passed through the first system and the second system is detected by a multi-channel detector. , the concentration of the analyte is detected from the intensity ratio of the signal output corresponding to the analyte and the signal output corresponding to the reference substance generated in different channels of the multi-channel detector, and nine-curse spectroscopy. Quantitative analysis method using (2) The quantitative analysis method using Kerse spectroscopy according to claim 1, wherein the substance to be measured is silane gas or disilane gas, and the reference substance is generalized carbon. (3) a first means for oscillating the first Rade light for excitation; a second means for oscillating the Rade light of fringe 2 including the Stokes frequency of both the measured substance and the reference substance; a first chamber filled with the substance to be measured;
a second chamber filled with the reference substance at a predetermined concentration; a channel detector, and detects the concentration of the analyte from the intensity ratio of the signal output corresponding to the analyte and the signal output corresponding to the reference substance generated in each different channel of the one multi-channel detector. A quantitative analysis device using nine-curse spectroscopy.