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DE-202024107321-U1 - Analysis device

DE202024107321U1DE 202024107321 U1DE202024107321 U1DE 202024107321U1DE-202024107321-U1

Abstract

Analysis device (11, 11', 11'') for analyzing a sample substance using Raman spectroscopy, with a sample chamber (13) for receiving the sample substance, a laser system (17) for irradiating the sample substance located in the sample chamber (13) with laser light, a dispersive optical element (12, 35, 35') for spectral splitting of scattered light emanating from the irradiated sample substance, at least one detector unit (20) for receiving at least a part of the spectrally split scattered light and an electronic evaluation device (25) which is in signal communication with the at least one detector unit (20) and is configured to determine at least one Raman line (51, 52) on the basis of the scattered light received by the detector unit (20), wherein the detector unit (20) has two adjacent individual detectors (21, 22) which are configured to output respective separate signals (27), wherein the electronic evaluation device (25) is configured to take into account the signals (27) of both individual detectors (21, 22) of the detector unit (20) when determining the at least one Raman line (51, 52).

Assignees

  • ENDRESS HAUSER SICK GMBH CO KG

Dates

Publication Date
20260513
Application Date
20241217
Priority Date
20241217

Claims (12)

  1. Analysis device (11, 11', 11'') for analyzing a sample substance by means of Raman spectroscopy, comprising a sample chamber (13) for receiving the sample substance, a laser system (17) for irradiating the sample substance located in the sample chamber (13) with laser light, a dispersive optical element (12, 35, 35') for spectral splitting of scattered light emanating from the irradiated sample substance, at least one detector unit (20) for receiving at least a portion of the spectrally split scattered light, and an electronic evaluation device (25) which is in signal communication with the at least one detector unit (20) and is configured to determine at least one Raman line (51, 52) based on the scattered light received by the detector unit (20), the detector unit (20) comprising two adjacent individual detectors (21, 22) which are configured to output respective separate signals (27) are designed, wherein the electronic evaluation device (25) is designed to take into account the signals (27) of both individual detectors (21, 22) of the detector unit (20) when determining the at least one Raman line (51, 52).
  2. Analysis device according to Claim 1 , wherein the analysis device (11, 11', 11'') comprises an adjusting device (36, 36') configured to transfer the relevant portion of the scattered light from one of the individual detectors (21, 22) to the other individual detector (21, 22) for the determination of the at least one Raman line (51, 52).
  3. Analysis device according to Claim 2 , wherein the electronic evaluation device (25) is configured to compare the signal (27) of at least one of the individual detectors (21, 22) and preferably the signals (27) of both individual detectors (21, 22) before and after the relocation.
  4. Analysis device according to Claim 2 or 3 , wherein the dispersive optical element (12) comprises a diffraction grating (35, 35') arranged and configured such that the portion of the scattered light corresponding to a predetermined Raman line (51, 52) is directed onto the detector unit (20), wherein the diffraction grating (35, 35') is rotatable about an axis of rotation (41) and the The actuating device (36') comprises a controllable drive for the rotatable diffraction grating (35, 35').
  5. Analysis device according to one of the Claims 2 until 4 , wherein the laser system (17) comprises a tunable laser and the adjusting device (36) comprises an electronic control device (37) for changing the wavelength of the tunable laser.
  6. Analysis device according to one of the Claims 2 until 5 , wherein the positioning device comprises a controllable positioning device for moving the detector unit (20).
  7. Analysis device according to one of the preceding claims, wherein the individual detectors (21, 22) are designed as point detectors or as single-channel detectors.
  8. Analysis device according to one of the preceding claims, wherein the individual detectors (21, 22) are designed as silicon photomultipliers.
  9. Analysis device according to one of the preceding claims, wherein the electronic evaluation device (25) is configured to determine a concentration of a substance present in the sample substance based on the height of at least one Raman line (51, 52).
  10. Analysis device according to one of the preceding claims, wherein the electronic evaluation device (25) is configured to form and/or evaluate a difference and/or a ratio of the signals of the individual detectors (21, 22).
  11. Analysis device according to one of the preceding claims, wherein the electronic evaluation device (25) is configured to use the signal (27) of one of the individual detectors (21, 22) as the useful signal and the signal of the other individual detector (21, 22) as the reference signal when determining the at least one Raman line (51, 52).
  12. Analysis device according to one of the preceding claims, wherein the laser system (17) comprises a laser with variable spectral width and the electronic evaluation device (25) is configured to determine the at least one Raman line (51, 52) based on the change in the signals (27) of the individual detectors (21, 22) when the spectral width of the laser is changed.

Description

The invention relates to an analysis device for analyzing a sample substance by means of Raman spectroscopy, comprising a sample chamber for receiving the sample substance, a laser system for irradiating the sample substance located in the sample chamber with laser light, a dispersive optical element for spectral splitting of scattered light emanating from the irradiated sample substance, at least one detector unit for receiving at least a part of the spectrally split scattered light, and an electronic evaluation device which is in signal communication with the at least one detector unit and is configured to determine at least one Raman line on the basis of the scattered light received by the detector unit. Such devices are used, for example, for the non-contact determination of the concentration of individual substances in mixtures. The sample substance can be a gas or a gas mixture. Corresponding gas analysis devices are needed, for example, for monitoring industrial processes. However, liquids and solids can also be analyzed using Raman spectroscopy. Raman spectroscopy investigates the inelastic scattering of light by matter by spectrally analyzing the light scattered by a substance. The detected frequency shifts compared to the incident light result from quantized rotational, vibrational, and rotational-vibrational transitions and are characteristic of different types of molecules. Accordingly, Raman spectroscopy enables both the structural analysis of molecules and the qualitative and quantitative detection of substances. Often, relatively complex mixtures containing many different substances need to be analyzed. Furthermore, there is an increasing demand for measurements of substances present in particularly low concentrations. Such analyses pose a challenge in practice. It is an object of the invention to provide an analytical device of the aforementioned type which has a high measurement sensitivity and a pronounced ability to distinguish between different substances. The problem is solved by an analysis device having the features of claim 1. According to the invention, the detector unit comprises two adjacent individual detectors, each configured to output separate signals, and the electronic evaluation unit is configured to consider the signals from both individual detectors of the detector unit when determining the at least one Raman line. The detector unit can, for example, be configured such that the individual detectors output their respective separate signals to the evaluation unit. By evaluating the two separate signals, improved spectral resolution can be achieved. In particular, the signals from both individual detectors can be correlated. This improved resolution makes it possible to reliably analyze even complex mixtures containing many different substances. The spectral resolution can be increased by evaluating the two separate signals, essentially independent of the spatial extent of the individual detectors. In particular, the position of a light spot incident on both individual detectors can be determined with exceptional accuracy by relating the signals of both detectors to each other. In this way, it is possible to reliably distinguish even substances that exhibit relatively closely spaced Raman lines. In general, the consideration of the signals from both individual detectors in the present disclosure is to be understood as generating an overall quantity relating to the Raman line, such as the spectral position, which incorporates both separate signals. In principle, determining the Raman line can include determining its spectral position, spectral width, and/or intensity. The spectral position generally correlates with a spatial position because the frequency of the light in the spectrometer is transformed into spatial space by means of a dispersive optical element—that is, an element that causes wavelength-dependent beam deflection—for example, using a prism or, preferably, a diffraction grating. It is preferably provided that the respective light-receiving surfaces of the individual detectors are adjacent to one another, optionally with an intermediate separating layer or separating layer. This results in a sharp transition from one individual detector to the next, which enables a particularly high spectral resolution. To create a suitable transition, at least one of the individual detectors can also have a light-receiving area that is limited in at least one spatial direction by an aperture element. The signal strength is then reduced, which, however, can be accepted in some applications. The analysis device for determining different Raman lines may include several differently positioned detector units, each with two adjacent individual detectors designed to output separate signals, for example, to the electronic evaluation unit. The positions of the detector units can be selected based on the expected Raman lines, which are spatially separated from each other by means of a di