Spectrometer and gas analyzer

Patent metadata

Field	Value
Publication number	US-9658154-B2
Application number	US-201615157709-A
Country	US
Kind code	B2
Filing date	May 18, 2016
Priority date	May 20, 2015
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A spectrometer has an entry aperture for coupling in electromagnetic radiation to be spectroscope, a refractive or diffractive optical element arranged such that electromagnetic radiation which is coupled in through the entry aperture is incident on the refractive or diffractive optical element to be spectrally split there, and at least two individual detectors which, for the detection of different spectral ranges of the split electromagnetic radiation, are arranged next to one another in the direction of the spectral splitting of the electromagnetic radiation. Electromagnetic radiation from a predetermined ultraviolet wavelength range is directed onto one of the individual detectors by the optical element and electromagnetic radiation from a predetermined blue wavelength range is directed onto another of the detectors by the optical element. Electromagnetic radiation from the intermediate wavelength range between the predetermined ultraviolet wavelength range and the predetermined blue wavelength range are not detected.

First claim

The invention claimed is:

1. A spectrometer for gas analysis in tunnel air monitoring, the spectrometer having an entry aperture for coupling in electromagnetic radiation to be spectroscoped; having a refractive or diffractive optical element which is arranged such that electromagnetic radiation which is coupled in through the entry aperture is incident on the refractive or diffractive optical element to be spectrally split there; and having at least two individual detectors which are located in the optical paths thereof for the detection of different spectral ranges of the split electromagnetic radiation,
wherein the at least two individual detectors are arranged next to one another in the direction of the spectral splitting of the electromagnetic radiation; and
wherein one of the at least two individual detectors is arranged such that electromagnetic radiation from an ultraviolet wavelength range between 190 nm and 250 nm is deflected onto it by the refractive or diffractive optical element and another one of the at least two individual detectors is arranged such that electromagnetic radiation from a blue wavelength range between 410 nm and 460 nm is deflected onto it by the refractive or diffractive optical element;
with electromagnetic radiation from the intermediate wavelength range between the said ultraviolet wavelength range and the said blue wavelength range not being detected.

2. The spectrometer in accordance with claim 1 , wherein the entry aperture is an entry gap.

3. The spectrometer in accordance with claim 1 , wherein the optical element for the spectral splitting is a diffractive optical element.

4. The spectrometer in accordance with claim 3 , wherein the diffractive optical element is a diffraction grating.

5. The spectrometer in accordance with claim 4 , wherein the diffraction grating is a planar grating with a constant grating constant.

6. The spectrometer in accordance with claim 1 , wherein the at least two individual detectors are arranged spaced apart from one another in the direction of the spectral splitting such that electromagnetic radiation in a predetermined spectral range is not incident on one of the detectors.

7. The spectrometer in accordance with claim 1 , wherein the at least two individual detectors are based on different detector technologies.

8. The spectrometer in accordance with claim 1 , wherein the at least two individual detectors are arranged at an angle with respect to one another which is spanned in the plane of the spectral splitting.

9. A gas analyzer having a spectrometer in accordance with claim 1 in which the entry aperture is an entry gap; having a light source; and having an optical measurement path arranged between the light source and the entry gap of the spectrometer for gas or gases to be examined spectrally using the gas analyzer.

10. A method of determining the presence and/or concentration of one or more gases using a gas analyzer in accordance with claim 9 , the method comprising the steps of:
determining the absorption taking place in the optical measurement path of the gas analyzer in a spectrally resolved manner by the spectrometer of the gas analyzer and determining at least one of the presence and the concentration of one or more gases from the absorption spectrum.

11. The method in accordance with claim 10 , wherein the gases whose presence and/or concentration is to be determined in the optical measurement path comprise NO, SO 2 , NH 3 and/or NO 2 .

12. The method in accordance with claim 10 , wherein the operating parameters of the at least two individual detectors are selected differently on the operation of the gas analyzer.

13. The method in accordance with claim 10 , wherein the read-out times of the at least two individual detectors are selected differently on the operation of the gas analyzer.

14. A spectrometer having an entry aperture for coupling in electromagnetic radiation to be spectroscoped; having a refractive or diffractive optical element which is arranged such that electromagnetic radiation which is coupled in through the entry aperture is incident on the refractive or diffractive optical element to be spectrally split there; and having at least two individual detectors which are located in the optical paths thereof for the detection of different spectral ranges of the split electromagnetic radiation,
wherein the at least two individual detectors are arranged next to one another in the direction of the spectral splitting of the electromagnetic radiation; and
wherein one of the at least two individual detectors is arranged such that electromagnetic radiation from a predetermined ultraviolet wavelength range is deflected onto it by the refractive or diffractive optical element and another one of the at least two individual detectors is arranged such that electromagnetic radiation from a predetermined blue wavelength range is deflected onto it by the refractive or diffractive optical element;
with electromagnetic radiation from the intermediate wavelength range between the predetermined ultraviolet wavelength range and the predetermined blue wavelength range not being detected; and
wherein the at least two individual detectors are based on different detector technologies.

15. The spectrometer in accordance with claim 14 , wherein the entry aperture is an entry gap.

16. The spectrometer in accordance with claim 14 , wherein the optical element for the spectral splitting is a diffractive optical element.

17. The spectrometer in accordance with claim 16 , wherein the diffractive optical element is a diffraction grating.

18. The spectrometer in accordance with claim 17 , wherein the diffraction grating is a planar grating with a constant grating constant.

19. The spectrometer in accordance with claim 14 , wherein the at least two individual detectors are arranged spaced apart from one another in the direction of the spectral splitting such that electromagnetic radiation in a predetermined spectral range is not incident on one of the detectors.

20. The spectrometer in accordance with claim 14 , wherein the at least two individual detectors are arranged at an angle with respect to one another which is spanned in the plane of the spectral splitting.

21. A gas analyzer having a spectrometer in accordance with claim 14 in which the entry aperture is an entry gap; having a light source; and having an optical measurement path arranged between the light source and the entry gap of the spectrometer for gas or gases to be examined spectrally using the gas analyzer.

22. A method of determining the presence and/or concentration of one or more gases using a gas analyzer in accordance with claim 21 , the method comprising the steps of:
determining the absorption taking place in the optical measurement path of the gas analyzer in a spectrally resolved manner by the spectrometer of the gas analyzer and determining at least one of the presence and the concentration of one or more gases from the absorption spectrum.

23. The method in accordance with claim 22 , wherein the gases whose presence and/or concentration is to be determined in the optical measurement path comprise NO, SO 2 , NH 3 and/or NO 2 .

24. The method in accordance with claim 22 , wherein the operating parameters of the at least two individual detectors are selected differently on the operation of the gas analyzer.

25. The method in accordance with claim 22 , wherein the read-out times o

Assignees

• Sick Ag

Inventors

• Convent Jurgen
• Trick Torsten
• Bonisch Andreas

Classifications

• G01J3/18

  using diffraction elements, e.g. grating (gratings per se G02B) · CPC title

• G01J3/427

  Dual wavelengths spectrometry · CPC title

• G01N21/31

  Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} · CPC title

• G01N21/33 Primary

  using ultraviolet light (G01N21/39 takes precedence) · CPC title

• G01J3/0291

  Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements · CPC title