UBIQUITOUS TRANSMISSIVE RAMAN SPECTROSCOPY FOR STAND-OFF DETECTION

• US 20160084765A1
• Filed: 09/24/2014
• Published: 03/24/2016
• Est. Priority Date: 09/24/2014
• Status: Active Grant

• Current Assignee: Smiths Detection (Smiths Group International Holdings Ltd.)
• Original Assignee: Smiths Detection (Smiths Group International Holdings Ltd.)
• Inventors: Lee, Vincent Yuan-Hsiang
• Granted Patent: US 10,436,716 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

A substance analysis system and method are provided, the system disposable a variable stand-off distance from a substance in situ, including an emitter disposed to emit radiation onto the substance in situ, and a detector disposed the variable stand-off distance from the substance in situ, the detector comprising a receiver defining a substantially collimated collection path over the variable stand-off distance.

Claims

1. A substance analysis system disposable a variable stand-off distance from a substance in situ, the system comprising:

an emitter disposed to emit radiation onto the substance in situ; and

a detector disposed the variable stand-off distance from the substance in situ, the detector comprising a receiver defining a substantially collimated collection path over the variable stand-off distance.

2. The system of claim 1 wherein the receiver is configured to receive a transmission Raman signal from a substantially columnar portion of the substance.

3. The system of claim 1, wherein the system is configured to analyze substances within at least one of a container that is substantially opaque to visible light and a container substantially transparent to visible light.

4. The system of claim 1, further comprising a sensor configured to determine when a container is configured relative to the system such that a substance within the container may be analyzed by the system.

5. The system of claim 1, further comprising a processor configured to indicate the presence of predetermined components within the substance based on the output of a comparator.

6. The system of claim 1, further comprising a comparator configured to compare the wavelength of the received Raman signal with the wavelength of the emitted radiation.

7. The system of claim 1, wherein the angular distance between the entry point through a wall of a container of the emission path and the entry point through a wall of the container of the detection path is greater than zero degrees and less than 180 degrees, where the container includes the substance.

8. A method of transmission Raman analysis comprising:

emitting radiation towards a first wall portion of a container in situ, wherein emitted radiation becomes a diffusive light source within the container without formation of a distinct substance region; and

receiving a transmission Raman signal through a second wall portion of the container, the received signal including Raman radiation reflected from multiple portions of the container,

wherein the receiver is disposable a stand-off distance from the container in situ.

9. The method of claim 8, further comprising comparing the transmission Raman signal with the emitted radiation.

10. The method of claim 8, wherein the Raman signal is received through a collection path that is substantially collimated and unfocused on any distinct substance region within the container.

11. The method of claim 8, wherein no reference beam is used, the method further comprising:

receiving a Raman signal including container background information;

looking up matching container background information; and

subtracting the looked-up container background information from the received Raman signal.

12. The method of claim 11, wherein the matching container background information is selected from a table comprising entries for a plurality of glass types and a plurality of plastic types.

13. The method of claim 8, wherein the emitted radiation follows an incident non-reflected path that intersects a collection path of the Raman radiation corresponding to the received Raman signal.

14. The method of claim 8, wherein at least one of the emitted radiation or Raman radiation illuminates the entire contents of the container by the internal reflection of radiation between the inner walls of the container.

15. The method of claim 8, wherein a Raman signal is generated from multi-path excitation of a whole liquid substance within the container.

16. The method of claim 8, wherein the Raman signal is at least one of omni-directional or ubiquitous.

17. The method of claim 8, wherein the container is generally opaque to visible light.

18. The method of claim 8, wherein said first wall portion is defined by an outer surface of the container, and said second wall portion is defined by an inner surface of the container directly interior to said outer surface.

19. A method of analyzing a substance in a container in situ a variable stand-off distance from a substance analysis system, the container having an interior surface and an exterior surface, the method comprising:

directing a beam of radiation at the container such that at least a portion of the radiation passes through the container and is scattered in the substance and at least a portion of the scattered radiation reflects off of the interior surface of the container, the radiation in the substance resulting in emission of a Raman signal representative of the contents of the substance at a plurality of locations within the substance;

detecting the Raman signal representative of the contents of the substance from a plurality of locations within the substance; and

comparing the Raman signal to the radiation of the radiation source.

20. The method of claim 19, further comprising:

wherein the directing comprises at least one of;

directing a beam of radiation at a container generally opaque to visible light and detecting the Raman signal representative of the contents of a substance contained in the generally opaque container;

or

directing a beam of radiation at a non-opaque container and detecting the Raman signal representative of the contents of a substance contained in the non-opaque container.

21. The method of claim 19, wherein the radiation source is a laser of between approximately 50 mW and 500 mW.

22. The method of claim 19, wherein the substance comprises a liquid substance.

23. The method of claim 19, wherein the radiation source is configured to emit a beam of radiation sufficient that a substance contained in a generally opaque container will emit a transmission Raman signal sufficient for the detecting the Raman signal.

24. The method of claim 19, wherein the radiation in the substance is reflected in the container;

and

wherein the radiation travels in the substance resulting in emission of Raman radiation at various angular orientations with respect to each other, respectively.

25. A method of analyzing liquid substances in both generally opaque to visible light containers and generally transparent containers, respectively, using a substance analysis system disposable a variable stand-off distance from the liquid substances in situ, comprising:

directing a beam of radiation at a first location on a container containing a liquid substance;

directing a detector at a second location on the container, the second location being different from the first location;

wherein the beam of radiation and the detector are configured so a sufficient amount of radiation from the beam passes through the container and into the substance to produce a sufficient transmission Raman signal including Raman radiation from a plurality of locations in the substance so the detector can detect the transmission Raman signal, the transmission Raman signal being indicative of the composition of the substance;

comparing the transmission Raman signal with the radiation emitted by the emitter;

determining based on a library of characteristics of components of interest whether the transmission Raman signal indicates that the substance contains a component of interest; and

outputting whether or not the substance contains a component of interest.

26. The method of claim 25, wherein an intensity of the transmission Raman signal is angularly independent if the beam of radiation is directed at a generally opaque container.

27. The method of claim 25, further comprising determining whether the transmission Raman signal indicates that the substance contains at least one of acetone, cyclohexane, ethanol, ethylene glycol, or H₂O₂ and outputting a warning if it is determined that the transmission Raman signal indicates that the substance contains at least one of acetone, cyclohexane, ethanol, ethylene glycol, or H₂O₂.

28. The method of claim 25, wherein the first location is approximately 135°

from the second location.

29. The method of claim 25, further comprising before directing the beam of radiation at the first location on the container, detecting whether a container is located to receive the beam of radiation.

30. A substance analysis system disposable a variable stand-off distance from a container in situ, the system comprising:

an emitter configured to emit radiation directed at a first location on the container, at least a portion of the radiation passing through the container and into a substance in the container, with at least a portion of the radiation in the substance being reflected within the container; and

a detector with a receiving portion directed at a second location on the container, the detector being configured to receive a transmission Raman signal including Raman radiation from multiple portions of the substance,

wherein the radiation directed at a first location on the container and the Raman radiation are substantially co-axial.

31. The system of claim 30, wherein the emitter is configured to emit focused radiation.

32. The system of claim 30, wherein the emitter is configured to emit non-focused radiation.

33. The system of claim 30, wherein the received radiation is columnar.

34. The system of claim 30, wherein the emitter is a stationary laser.

35. A substance analysis system disposable a variable stand-off distance from a container in situ, the system comprising:

a detector with a receiving portion directed at the container, the detector being configured to receive a reflected radiation signal from multiple portions of a substance in the container, the detector a stand-off distance from the container, where the receiving portion of the detector includes a collection aperture configured to receive a substantially collimated beam of radiation reflected from the substance in the container.

36. The substance analysis system of claim 35, where the collection aperture is approximately five mm in diameter.

37. The substance analysis system of claim 35, where the container is substantially opaque.