PORTABLE MEMS-BASED SPECTRAL IDENTIFICATION SYSTEM

• US 20090252650A1
• Filed: 08/16/2007
• Published: 10/08/2009
• Est. Priority Date: 08/16/2006
• Status: Abandoned Application

• Current Assignee: Sridhar Lakshmanan
• Original Assignee: Sridhar Lakshmanan
• Inventors: Lakshmanan, Sridhar
• Application Number:
  US12/310,266
• Publication Number:
  US 20090252650A1
• Time in Patent Office: Days
• US Class Current: 422/91
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

A sensing arrangement detects a compound of interest within a gas sample. An amplifying fluorescent polymer produces an output signal that varies in response to an interaction of the amplifying fluorescent polymer with the compound of interest. Additionally, an infrared illumination source produces infrared electromagnetic energy that causes the amplifying fluorescent polymer to generate the output signal. A MEMS detector is positioned to receive the output signal generated by the amplifying fluorescent polymer, and produces an output electrical signal that is responsive to an interaction between the compound of interest and the amplifying fluorescent polymer. The output electrical signal is responsive to a quenching of the output signal of the amplifying fluorescent polymer. A pattern database stoics pattern data corresponding to characteristics of compounds of interest.

Claims

1. A detector arrangement for detecting a compound that is present in an air sample, the arrangement comprising:

a chamber for receiving the air sample, said chamber having an inlet and an outlet communicating with the enclosed sensing volume;

a pump arrangement for urging the air sample into said chamber;

an illumination arrangement for causing electromagnetic energy having a first spectral characteristic to be propagated through the air sample;

a sensor having an amplifying fluorescent polymer disposed within said chamber, said sensor being disposed to communicate with the air sample; and

a detector for receiving a portion of the electromagnetic energy, said detector further having an output for issuing an output signal responsive to the spectral characteristic of the received portion of the electromagnetic energy, the received portion of the electromagnetic energy having a second spectral characteristic that differs from the first spectral characteristic in response to the compound.

2. The detector arrangement of claim 1, wherein said illumination arrangement is a source of infrared energy.

3. The detector arrangement of claim 2, wherein said detector is a tunable infrared detector.

4. The detector arrangement of claim 1, wherein there is further provided a pattern database for storing pattern data corresponding to characteristics of compounds of interest.

5. The detector arrangement of claim 4, wherein there is further provided a processor for comparing data contained in the output signal of said detector to the pattern data stored in said pattern database.

6. The detector arrangement of claim 4, wherein said pattern data corresponds to a spectral absorption characteristic.

7. The detector arrangement of claim 1, wherein said detector is a MEMS detector.

8. The detector arrangement of claim 1, wherein said detector receives an illumination produced by said sensor.

9. A sensing arrangement for detecting a compound of interest within a gas sample, the sensing arrangement comprising:

an amplifying fluorescent polymer for producing an output signal that varies in response to an interaction of the amplifying fluorescent polymer with the compound of interest;

an infrared illumination source for producing infrared electromagnetic energy that causes said amplifying fluorescent polymer to generate the output signal; and

a MEMS detector positioned to receive the output signal generated by the amplifying fluorescent polymer, said MEMS detector producing an output electrical signal responsive to an interaction between the compound of interest and said amplifying fluorescent polymer.

10. The sensing arrangement of claim 9, wherein the output electrical signal is responsive to a quenching of the output signal of said amplifying fluorescent polymer.

11. The sensing arrangement of claim 9, wherein there is further provided a pattern database for storing pattern data corresponding to characteristics of compounds of interest.

12. A system for detecting explosives of interest from a standoff distance in response to chemical vapors associated with the explosives of interest, The explosives of interest being of the type that absorb infrared energy at predetermined wavelength notches in the 2-20 micron band, the system comprising:

a chamber for receiving the chemical vapors desired to be detected;

a heat source for emitting infrared radiation into said chamber, the infrared radiation having energy in the spectral region of the 2-20 micron band, and

a spectrally tuned infrared detector for detecting a change in the infrared energy in the predetermined wavelength notches in the 2-20 micron band.

13. The system of claim 12, wherein the chemical vapors associated with the explosives of interest are selected from the group consisting of TNT, RDX, HMX, PETN, Tetryl, NG, NC, Taggants (DMNB and EGDN), C-4, SEMTEX, ANFO;

plastic bonded explosives (PE and LTPA); and

non-nitro explosives (TATP and HMTD).

14. The system of claim 12, wherein the spectrally tuned infrared detector comprises an infrared camera having spectrally selective diffractive optics.

15. The system of claim 14, wherein the selection of the spectral sensitivity of the diffractive optics is determined by linear discriminant methods.

16. The system of claim 14, wherein the spectral sensitivity of the diffractive optics is determined by mechanical articulation of the diffractive optics.

17. The system of claim 12, wherein the spectrally tuned infrared detector comprises a thermally cooled infrared camera.