JP2015175708A - Raman spectroscopic analyzer and raman spectroscopic analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise of backscattering light in a Raman spectroscopic analyzer which irradiates a sample with excitation light via a sample chamber window to detect backscattering light from the sample.SOLUTION: A Raman spectroscopic analysis method includes: a step of reflecting an excitation luminous flux by a reflection mirror 104 and causing reflected light to perpendicularly pass a sample chamber window 107 and condensing the reflected light at a prescribed measurement point P in a sample chamber 106 to irradiate a sample at the measurement point P; and a step of causing Raman scattering light which is emitted backward from the sample and passes the sample chamber window 107 and is scattered around the reflection mirror 104, to impinge on a detection system 109 by a lens 108 with the measurement point P as a focus. Further, the Raman spectroscopic analysis method includes a step of reducing the amount of light from a mirror image point Q of the measurement point P with a surface of the sample chamber window 107 as a mirror surface, which impinges on the detection system 109.

Description

  The present invention relates to a component analysis apparatus and a component analysis method using Raman scattered light. In particular, the present invention relates to a Raman spectroscopic analysis apparatus and a Raman spectroscopic analysis method for detecting light scattered backward from a sample.

  An apparatus for analyzing components contained in a sample by performing Raman spectroscopic measurement includes a light source that emits light (excitation light) that irradiates the sample, an incident optical system that collects the excitation light and irradiates the sample, and the sample A spectroscopic optical system that condenses and separates light scattered by Raman scattering by interaction with a substance contained therein, and a detection system that detects light separated in wavelength in the spectroscopic optical system.

  Plotting the intensity of light from the sample with the horizontal axis representing the wavelength and the vertical axis representing the intensity, Raman having a Stokes line on the long wavelength side and an anti-Stokes line on the short wavelength side centered on the wavelength of the excitation light (Rayleigh scattered light) A scattering spectrum is obtained. When the Raman scattering spectrum is drawn with the horizontal axis representing the wave number of the excitation light as the origin, the value of the Stokes line wave number (Stokes shift) corresponds to the natural vibration energy of the substance interacting with the excitation light. The substance contained in the sample can be specified from the Stokes shift value. Further, the substance corresponding to the Stokes line can be quantified from the peak intensity or peak area of the Stokes line.

  Patent Document 1 and Patent Document 2 describe a gas component analyzer that measures components contained in a gas generated in a coal gasifier and the concentration of each component by performing Raman spectroscopic measurement. FIG. 7 shows the main configuration of this apparatus. In this gas component analyzer 700, excitation light emitted from a laser light source 701 is collected by a lens 702, passes through a beam splitter 703 and a sample chamber window 704, and is passed through a predetermined gas in the sample gas introduced into the sample chamber 705. Irradiate the spot. Light (scattered light) scattered from the gas to the irradiation side (backward) of the excitation light is extracted from the sample chamber window 704, reflected by the beam splitter 703, condensed by the lens 706, and a detection system provided with a spectroscopic optical system. 707. Furthermore, using the data analysis device 708, a Raman scattering spectrum of the sample gas is created from the detection result of the backscattered light in the detection system 707, the component contained in the sample gas is specified, and the concentration of each component is determined.

The beam splitter 703 and the sample chamber window 704 are made of a material having a high light transmittance at the wavelength of the excitation light, and the surface thereof is subjected to an anti-reflection coating process (also referred to as an AR coat) in order to minimize reflection. ing. By applying the anti-reflection coating process, the reflection of the excitation light in the sample chamber window 704 can be reduced to about 1%. About a 1% portion of the excitation light that has passed through the beam splitter 703 and reflected by the sample chamber window 704 is reflected by the beam splitter 703 and travels toward the lens 706. For this reason, the excitation light emitted from the light source is reduced to about 10 ⁻⁴ times, enters the lens 706, and is detected by the detection system 707.

Japanese Patent Laid-Open No. 11-173989 JP 2004-325458 A

  There is a great demand for the development of a high-sensitivity Raman spectrometer with a large signal-to-noise ratio (S / N ratio). In particular, when detecting a very small amount of gas component, the signal intensity decreases, and therefore it is required to reduce noise in order to increase the signal-to-noise ratio. As described above, by applying the anti-reflection coating to the sample chamber window 704, noise due to reflection of excitation light in the sample chamber window 704 has been reduced, but noise is still detected by the detection system.

  The present invention has been made in view of the above points, and its object is to irradiate a sample with excitation light through a sample chamber window and detect backscattered light from the sample. 1 is to reduce the noise of backscattered light.

  As a result of intensive investigation of the cause of noise still being detected even when reflection from the sample chamber window is reduced, the inventors have released scattered light from the substance (gas) in the optical path of the excitation light. I found out that That is, the scattered light from the substance in the optical path at the mirror image point that is in a mirror image symmetry position with respect to the focal point of the excitation light with respect to the surface of the sample chamber window is reflected by the surface of the sample chamber window and condensed by the condensing lens to the detection system. The incident light was found to constitute noise of backscattered light. Thus, the present invention has been made on the assumption that noise caused by substances in the optical path can be reduced by reducing the amount of scattered light from the mirror image point detected by the detection system.

The Raman spectroscopic analysis method according to the present invention made to solve the above problems is as follows:
a) reflecting the excitation light beam by a reflecting mirror, passing the sample chamber window vertically, condensing it at a predetermined measurement point in the sample chamber, and irradiating the sample at the measurement point;
b) a step of allowing Raman scattered light, which is emitted backward from the sample and passed through the sample chamber window and scattered around the reflecting mirror, to enter the detection system by the lens having the measurement point as a focus. Having a Raman spectroscopy method,
c) reducing the amount of light incident from the mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface entering the detection system.

  The sample that can be analyzed by the Raman spectroscopic analysis method according to the present invention may be a gas or a liquid as long as it is a fluid that can be accommodated (or distributed) in the sample chamber.

  This process of reducing the amount of light incident from the mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface can be realized by the following three methods.

  The first method is such that the mirror image point exists before the reflector, i.e., the mirror image point is not between the sample chamber window and the reflector, but between the reflector and the excitation light source. In this method, the positional relationship between the reflecting mirror and the sample chamber window is set.

  As a result, the scattered light generated in the gas existing at the mirror image point by the excitation light has a range in which the scattered light is incident on the sample chamber window compared to the case where the position of the mirror image point is between the sample chamber window and the reflecting mirror. Since it becomes narrow, the amount of scattered light reflected by the surface of the sample chamber window and entering the detection system is reduced.

  The second method is a method of providing a cylindrical shield that surrounds the optical axis of the excitation light beam from the reflecting mirror toward the sample chamber window.

  As a result, since the scattered light generated by the gas existing at the mirror image point by the excitation light is reflected by the surface of the sample chamber window, the portion of the light that spreads beyond the reflecting mirror is shielded by the cylindrical shield, It will not enter the detection system. Since the scattered light that has passed through the cylindrical shield in the optical axis direction is reflected by the reflecting mirror, it also does not enter the detection system.

  The third method is a method in which a gas that does not generate Raman scattered light (for example, an inert gas such as argon Ar) is present at the mirror image point, or the mirror image point is evacuated.

  As a result, since no Raman scattered light is generated at the mirror image point, such noise is prevented from entering the detection system.

Corresponding to the first method, the Raman spectroscopic analyzer according to the present invention made to solve the above problems,
a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
With
The reflecting mirror is arranged at a distance from the sample chamber window such that a mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface is not formed between the sample chamber window and the reflecting mirror. It is characterized by.

Corresponding to the second method, the Raman spectroscopic analyzer according to the present invention made to solve the above problems,
a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
c) a cylindrical shield surrounding the optical axis of the excitation light beam from the reflecting mirror toward the sample chamber window;
Is provided.

Corresponding to the third method, the Raman spectroscopic analyzer according to the present invention made to solve the above problems,
a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
c) a vacuum vessel in which the atmosphere at the position of the mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface is vacuum or a predetermined gas atmosphere;
Is provided.

  According to the Raman spectroscopic analysis method and the Raman spectroscopic analysis apparatus according to the present invention, the scattered light generated by the gas existing at the mirror image point is reflected by the surface of the sample chamber window by the excitation light before being irradiated onto the sample. As a result, it is no longer incident on the detection system or the amount of incident light is reduced. For this reason, noise incident on the detection system is reduced, and Raman scattered light derived from the sample can be measured with higher sensitivity.

1 is a schematic configuration diagram of a Raman spectroscopic analyzer according to Embodiment 1 of the present invention. FIG. 1 is a partially enlarged view of a Raman spectroscopic analyzer according to Embodiment 1. FIG. The schematic block diagram of the Raman spectroscopic analyzer which concerns on Example 2 of this invention. FIG. 4 is a partially enlarged view of a Raman spectroscopic analyzer according to Embodiment 2. The schematic block diagram of the Raman spectroscopy analyzer which concerns on Example 3 of this invention. The figure explaining the example of the reflective mirror supported by the support body used in Examples 1-3. The schematic block diagram of the gas component analyzer of a prior art.

Example 1
FIG. 1 is a schematic configuration diagram of a Raman spectroscopic analyzer according to the present embodiment, and FIG. 2 is a partially enlarged view thereof. 1 includes a light source 101, an irradiation condensing unit 102, a filter 103, a reflecting mirror 104 supported by a support 105, a sample chamber 106 provided with a sample chamber window 107, a lens 108, and a detection system. 109 and a shield 112.

  The Raman spectroscopic analyzer 100 can measure a gas or liquid fluid sample, but can be suitably used for a gas sample. Further, a case where the sample chamber 106 is a gas pipe for flowing gas will be described.

As the light source 101, a laser light source that emits visible light can be used, and a solid-state laser such as a YAG laser or a YVO ₄ laser, or a gas laser such as an Ar laser can be used. The irradiation condensing unit 102 can use an optical element such as a convex lens having a high transmittance with respect to the wavelength of visible light emitted from the light source 101.

  The excitation light beam emitted from the light source 101, which is a laser light source, is collected by a convex lens that constitutes the irradiation condensing unit 102, and is condensed on the sample measurement point in the sample chamber 106 through the sample chamber window 107. For the sample chamber window 107, a material having a high light transmittance at the wavelength of the light beam, such as quartz, is used. The excitation light beam that has passed through the irradiation condensing unit 102 passes through the filter 103 and enters the reflecting surface of the reflecting mirror 104 supported by the support 105.

  The filter 103 removes light other than the main wavelength of the excitation light beam emitted from the light source 101.

  In this embodiment, as shown in FIG. 6A, the support body 105 and the reflecting mirror 104 are respectively located on the brace and the support body 105 composed of a circular frame and braces provided in the frame. And a reflecting mirror 104 formed of a mirror provided at the center of the circular frame. The support 105 is made of a material such as stainless steel (SUS304) that does not emit light that is unnecessary in this measurement, such as fluorescence, even when scattered light such as laser or Rayleigh light hits it. A material that reflects excitation light with high reflectance is used for the reflecting mirror 104. In this embodiment, the case where the shape of the reflecting surface of the reflecting mirror 104 is a circle or an ellipse will be described. However, it is sufficient that the reflecting surface has a sufficient area for reflecting the light beam. Other shapes may be used.

  The excitation light beam incident on the reflecting surface of the reflecting mirror 104 is reflected by the reflecting surface so that its traveling direction is bent and enters the sample chamber window 107 perpendicularly. The excitation light beam vertically incident on the sample chamber window 107 is condensed on the sample (gas) in the sample chamber 106 and becomes excitation light for exciting the sample at the condensing position (measurement point). From the sample, scattered light such as Rayleigh scattered light, which is light having the same wavelength as the excitation light, and Raman scattered light, which is light having a wavelength different from that of the excitation light, is emitted from the sample in various directions.

  Among these scattered light, backscattered light that is scattered in the direction opposite to the direction in which excitation light is incident on the sample passes through the sample chamber window 107, and reflects the reflecting mirror 104 and the support 105 with these. Scattered around. In this embodiment, some backscattered light is shielded by the reflective surface of the reflector 104 and the circular frame of the support 105, but most of the backscattered light passes between the circular frame and the brace of the support 105. As a result, the light is received from the sample chamber 106 by the lens 108 disposed farther than the reflecting mirror 104 and the support 105.

  When the diameter of the reflecting mirror 104 is d and the diameter of the support 105 is D, it is preferable to have a ratio of d: D = 1: 10. For example, d = 5 mm and D = 50 mm can be used. With such a size, the shielding area by the reflecting mirror 104 can be made sufficiently smaller than the light receiving area by the lens 108. Thereby, the signal loss of the backscattered light shielded by the reflecting surface of the reflecting mirror 104 is negligible.

  The lens 108 is arranged so that the condensing position (measurement point) where the excitation light beam is condensed on the sample is the focal point P, and the backscattered light received by the lens 108 is collimated by the lens 108. The collimated backscattered light is introduced into a detection system 109 including a spectroscopic optical system, and the backscattered light from the sample is detected by the detection system 109. Thereby, the Raman spectroscopic measurement of the sample is performed.

  In the present embodiment, the excitation light beam emitted from the light source 101 and passing through the irradiation condensing unit 102 and the filter 103 is bent in the traveling direction by the reflecting surface of the reflecting mirror 104, and then from the reflecting mirror 104 to the sample chamber window 107. A cylindrical shield 112 that surrounds the optical axis of the excitation light beam traveling is provided between the reflecting mirror 104 and the sample chamber window 107. The cylindrical shield 112 can be a circular cross section perpendicular to the longitudinal direction of the cylinder (cylinder) or a polygonal (square pillar), and the inside of the cylinder is hollow. Further, the cylinder may not be straight, such as a tapered shape. One end of the cylindrical shield 112 is in contact with the sample chamber window 107 or is arranged with a slight gap. If the other end of the cylindrical shield 112 is in front of the reflecting mirror 104, the function is sufficient. However, in order to support the cylindrical shielding object 112, the reflecting mirror 104 is used as a cylinder of the cylindrical shielding object 112. The other end of the cylindrical shield 112 may be in contact with the support 105. In this case, an opening S is provided in the cylindrical shield 112 so that the excitation light beam passes through the reflecting surface of the reflecting mirror 104.

  The material of the cylindrical shield 112 is selected so that it does not easily emit light that is unnecessary in the main measurement, such as fluorescence, even when scattered light strikes it.

  Since the excitation light beam is condensed on the sample in the sample chamber 106 by the irradiation condensing unit 102, the diameter of the excitation light beam decreases from the reflecting mirror 104 toward the sample chamber window 107, and the tube shape is reduced. It passes through the cavity inside the cylinder of the shield 112. That is, the excitation light beam is not affected by the shield 112 at all.

  On the other hand, some of the backscattered light from the sample that is shielded by the shield 112 is reflected by the shield 112, and if this reflection occurs inside the cylinder of the cylindrical shield 112, sometimes The light is reflected in the direction in which the light source 101 is provided by the reflecting surface of the reflecting mirror 104 through the hollow inside the tube of the cylindrical shield 112 while repeating the reflection. Therefore, some of such backscattered light is not received by the lens 108 and is not detected by the detection system 109. On the other hand, most of the backscattered light passes outside the shield 112 and is received by the lens 108 and detected by the detection system 109. Therefore, the influence of the cylindrical shield 112 on the backscattered light from the sample is small.

  Such a cylindrical shield 112 exhibits its effect by surrounding a mirror image point Q with the surface of the sample chamber window 107 at the condensing position (measurement point) of the excitation light beam as a mirror surface. The mirror image point Q is located in the optical path of the excitation light beam, and since the excitation light beam is scattered by the substance (gas) existing at the mirror image point Q, the scattered light is emitted from the mirror image point Q. In the case where the cylindrical shield 112 is not provided, the light (scattered light) from the mirror image point Q is incident on all regions of the sample chamber window 107, and then the light reflected by the surface of the sample chamber window 107 is reflected by the lens 108. The light is received and detected by the detection system 109. On the other hand, when the cylindrical shielding object 112 is provided as described above, the traveling direction of the light from the mirror image point Q is limited by the shielding object 112 in the longitudinal direction of the cylinder, and the cylindrical shielding object is sometimes repeatedly reflected. It passes through the cavity inside the cylinder of the object 112 and enters the sample chamber window 107 or the reflecting mirror 104 located at the end of the cylinder.

  The light from the mirror image point Q incident on the sample chamber window 107 located at one end of the cylinder is reflected on the surface of the sample chamber window 107, but the portion of the light that is wider than the reflector 104 is cylindrically shielded. The object 112 is shielded and guided to the reflecting mirror 104 located at the other end of the cylinder. Since the light from the mirror image point Q that has entered the reflecting mirror 104 is reflected in the direction in which the light source 101 is provided, it is not received by the lens 108 and is not detected by the detection system 109. Therefore, the light from the mirror image point Q is not detected by the detection system 109, and the noise of the backscattered light from the sample can be reduced.

(Example 2)
FIG. 3 is a schematic configuration diagram of the Raman spectroscopic analyzer according to the present embodiment, and FIG. 4 is a partially enlarged view thereof. The same components as those in FIG. 1 are denoted by the same reference numerals, and repeated description is omitted. The Raman spectroscopic analysis apparatus 200 according to the present embodiment is configured so that the mirror image point exists ahead (upstream) of the reflecting mirror, that is, no mirror image point is formed between the sample chamber window 107 and the reflecting mirror 104. The reflecting mirror 104 is arranged at a distance from the sample chamber window 107. In other words, the distance between the sample chamber window 107 and the reflecting mirror 104 is shorter than the distance between the sample chamber window 107 and the condensing position (measurement point) of the excitation light beam.

  In this embodiment, as shown in FIG. 6A, the support body 105 and the reflecting mirror 104 are respectively located on the brace and the support body 105 composed of a circular frame and braces provided in the frame. And a reflecting mirror 104 formed of a mirror provided at the center of the circular frame. Also in the present embodiment, the mirror image point Q is located in the optical path of the excitation light beam, and the excitation light beam is scattered by the substance (gas) existing at the mirror image point Q, so that scattered light is emitted from the mirror image point Q. .

  In the case where the mirror image point Q with the surface of the sample chamber window 107 at the condensing position (measurement point) of the excitation light beam as a mirror surface is between the sample chamber window 107 and the reflecting mirror 104, the scattered light from the mirror image point Q is scattered in the sample chamber. The light is reflected by the entire area of the surface of the window 107 and received by the lens 108 and detected by the detection system 109. On the other hand, in the configuration of this embodiment in which the reflecting mirror 104 is arranged at a distance from the sample chamber window 107 so that no mirror image point is formed between the sample chamber window 107 and the reflecting mirror 104, the mirror image points emitted in various directions are used. Most of the light from Q is not received by the lens 108. A part of the light from the mirror image point Q directly passes through the support 105 and is received by the lens 108, but is not collimated even though it passes through the lens 108. Therefore, such light is not detected because it does not enter the detection system 109 correctly. In the configuration of the present embodiment, the scattered light from the mirror image point Q is reflected by the reflecting surface of the reflecting mirror 104, then enters the partial region 210 of the sample chamber window 107, and is reflected by the surface of the sample chamber window 107. Is done. The scattered light from the mirror image point Q reflected by the surface of the sample chamber window 107 is received by the lens 108 and detected by the detection system 109. However, the scattered light from the mirror image point Q has a narrower range in which the scattered light is incident on the sample chamber window 107 as compared with the case where the mirror image point Q is positioned between the sample chamber window 107 and the reflecting mirror 104. The amount of scattered light that is reflected by the surface of the chamber window 107 and enters the detection system 109 is reduced. Therefore, the detection amount of the light from the mirror image point Q in the detection system 109 is reduced, and noise of backscattered light from the sample can be reduced.

(Example 3)
FIG. 5 is a schematic configuration diagram of the Raman spectroscopic analyzer according to the present embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals, and repeated description is omitted. The Raman spectroscopic analysis apparatus 300 according to this embodiment includes a vacuum container 310, a gas introduction valve 311, a gas exhaust valve 312, a vacuum pump 313, a gas cylinder 314, etc. for making the atmosphere at the mirror image point a vacuum or a predetermined gas atmosphere. Is included. As the predetermined gas atmosphere, an example is described in which an inert gas atmosphere is used in which Raman scattered light such as Ar is not generated, or even if generated, the amount is negligible.

  The vacuum vessel 310 is provided in contact with the sample chamber 106, and the sample chamber window 107, the support 105, and the light collecting unit 102 are embedded in the side wall of the vacuum vessel 310. The filter 103 and the reflecting mirror 104 are provided inside the vacuum vessel 310, and the filter 103 is supported in the vacuum vessel 310 by a support (not shown). The vacuum vessel 310 is provided with a gas introduction port connected to a gas cylinder 314 via a gas introduction valve 311. Further, the vacuum vessel 310 is provided with a gas discharge port connected to the vacuum pump 313 via a gas exhaust valve 312. As the vacuum pump 313, a pump capable of achieving a desired degree of vacuum such as a rotary pump or a turbo molecular pump can be used. The gas introduction valve 311 and the gas exhaust valve 312 can control the flow rate of the gas flowing through the valve positions. The vacuum vessel 310, the gas introduction valve 311, the gas exhaust valve 312, the vacuum pump 313, and the gas cylinder 314 function as an atmosphere control unit, and control the inside of the vacuum vessel 310 to a vacuum or an inert gas atmosphere.

  When the atmosphere at the position of the mirror image point Q is not set to a vacuum or a predetermined gas atmosphere, atmospheric components such as oxygen and nitrogen exist at the position of the mirror image point Q, and Raman scattered light derived therefrom is generated. On the other hand, when the atmosphere at the position where the mirror image point is formed is set to a vacuum or an atmosphere of gas inert to Raman scattering by the atmosphere control unit as described above, oxygen or nitrogen is present at the position of the mirror image point Q. There are almost no atmospheric components, and substantially no Raman scattered light derived from them. Therefore, the noise of the backscattered light from the sample can be reduced.

  The said Examples 1-3 can be used individually or in combination suitably.

(Modification)
In the first to third embodiments, as shown in FIG. 6A, the support body 105 and the reflecting mirror 104 are each formed of a circular frame and a support body 105 formed of braces provided in the frame, and However, in the modified example, as shown in FIG. 6B, the support described in the first to third embodiments is configured. Each of the body 105 and the reflecting mirror 104 includes a circular support 615 made of a material that transmits light, such as quartz, and a reflecting mirror 614 made by depositing Al on glass.

  For the same reason as the reflecting mirror 104 and the support 105 described in the first embodiment, when the diameter of the reflecting mirror 614 is d ′ and the diameter of the support 615 is D ′, d ′: D ′ = 1: 10 or so. It is preferable to have a ratio, for example, d ′ = 5 mm and D ′ = 50 mm can be used. In this case, a part of the backscattered light emitted from the sample is shielded by the reflecting surface of the reflecting mirror 614, but most of the backscattered light passes through the support 615 and is received by the lens 108.

  In the case of using the support body 105, a part of the backscattered light is shielded by the brace and the circular frame of the support body 105, but in the case of using the support body 615, the backscattered light is shielded by the support body 615. There is no. Thereby, compared with the case where the support body 105 of Examples 1-3 is used, more backscattered light can be detected.

100, 200, 300, 700 ... Raman spectroscopic analyzer 101, 701 ... Light source 102 ... Irradiation condensing unit 103 ... Filter 104, 614 ... Reflector 105, 615 ... Support 106, 705 ... Sample chamber 107, 704 ... Sample chamber Window 108, 702, 706 ... Lens 109, 707 ... Detection system 112 ... Shielding object 310 ... Vacuum vessel 311, 312 ... Valve 313 ... Vacuum pump 314 ... Gas cylinder 703 ... Beam splitter 708 ... Data analysis device

Claims (4)

a) reflecting the excitation light beam by a reflecting mirror, passing the sample chamber window vertically, condensing it at a predetermined measurement point in the sample chamber, and irradiating the sample at the measurement point;
b) a step of allowing Raman scattered light, which is emitted backward from the sample and passed through the sample chamber window and scattered around the reflecting mirror, to enter the detection system by the lens having the measurement point as a focus. Having a Raman spectroscopy method,
c) A Raman spectroscopic analysis method comprising a step of reducing an amount of light from a mirror image point of the measurement point incident on the detection system with the surface of the sample chamber window as a mirror surface. a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
With
The reflecting mirror is arranged at a distance from the sample chamber window such that a mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface is not formed between the sample chamber window and the reflecting mirror. A Raman spectroscopic analyzer characterized by this. a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
c) a cylindrical shield surrounding the optical axis of the excitation light beam from the reflecting mirror toward the sample chamber window;
Raman spectroscopy analyzer. a) a reflecting mirror that reflects the excitation light beam, passes vertically through the sample chamber window, condenses on a predetermined measurement point in the sample chamber, and irradiates the sample at the measurement point;
b) a lens having a focus on the measurement point, which emits Raman scattered light emitted backward from the sample, passed through the sample chamber window, and scattered around the reflector, into a detection system;
c) a vacuum vessel in which the atmosphere at the position of the mirror image point of the measurement point with the surface of the sample chamber window as a mirror surface is vacuum or a predetermined gas atmosphere;
Raman spectroscopy analyzer.

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