Presentation on theme: "SPSA / SIPR Conference 2010 Remote Chemical Detection by Tunable Lasers : Potential applications in Threat Detection and Forensics Dr Graeme Malcolm."— Presentation transcript:
SPSA / SIPR Conference 2010 Remote Chemical Detection by Tunable Lasers : Potential applications in Threat Detection and Forensics Dr Graeme Malcolm
Acknowledgements Co-authors: G.T. Maker, B.Miller & G. Robertson, M Squared Lasers Ltd M.H. Dunn and D.J.M Stothard, University of St. Andrews, UK Co-workers : C.R Howle, A McIntosh, L.Lee and C.Dyer Defence Science and Technology Laboratory (DSTL), Porton Down, UK Work supported by: DSTL, MoD, Royal Society of Edinburgh, Scottish Enterprise.
Overview Active IR hyperspectral sensing concept Source requirements Source & imaging system Results Threat Detection and Forensic Applications Conclusion and Summary
www.m2lasers.com Introduction Problem: real-time detection & imaging of threat materials at safe distances CWAs, BWAs, IEDs, TICs Ideally detect many agents with one device ‘Safe’ distance typically ten(s) metres IED Threat Typical Explosives Mass (TNT Equivalent) Building Evacuation Distance Pipe Bomb2.3 kg (5 lbs)21 m (70 ft) Suicide Belt4.5 kg (10 lbs)27 m (90 ft) LPG Tank9 kg (20 lbs)48 m (160 ft) Ref: US Army, National Ground Intelligence Center, IED Safe Standoff Distances
Stand-off Concept Confidential - Feb ‘09 Threat Detection Concept M Squared Current Capability CWA Sensing
www.m2lasers.com Application Requirements: IR Threat Signatures C C C N C C C O X-H attached to hetero-atoms C-H Triples Double s Singles N H O H 4000 2000 3000 1000 2300 2100 1800 1500 2800 4000 3200 cm -1 5.0 2.5 10 3.3 µm cm -1 Typical absorption wavelengths of molecular bonds in common organic molecules
Active IR Hyperspectral Remote Sensing- Concept Use strong absorptions of target molecules or compounds in the IR waveband Illuminate scene with IR light of high spectral purity to coincide with absorption features Collect back-scattered light Target molecule/compound in path of beam will absorb and reduce backscatter Negative Contrast Imaging Tunable IR source Different absorption features measured and spectroscopic identification possible
3.03. 5 4.04.55.0 10 -17 10 -18 10 -19 10 -20 10 -21 10 -22 HCN C2H2C2H2 OH NH 3 H2OH2O BTEX CH 3 CI C2H4C2H4 NO 2 HCI CH 4 C2H6C2H6 H 2 CO HBr H2SH2S SO 2 CO 2 PH 3 N2ON2O OCS CO GeH 4 HI C2N2C2N2 O3O3 Wavelength (µm) Line Strength (cm/molecule) Spectroscopic survey of line strengths of in the 3-5µm infrared region
Source Requirements Sensitivity & specificity require sources with: High power & brightness (for range, high SNR) Broad wavelength tuning (cover many species) Suitable linewidth (selectivity) High efficiency and compactness (portability) Lack of suitable IR illuminators has hindered adoption of active IR hyperspectral sensing
Novel IR Illuminator - Firefly-IR OPO = broad tuning, dual NIR & MWIR outputs Intracavity OPO = high efficiency Integrated pump = compact Designed for field use: Maintenance-free design Instrument Control by Ethernet InvarianT™ alignment-free mounts 36 x 21 x 7cm (L x W X H)
Firefly-IR: Performance Characteristics Tuning ranges: 1.4 - 1.8 µm (>300 mW) 2.8 - 4.6 µm (>120 mW) Pulse repetition rate: Up to 300 kHz Pulse width: < 10 ns (FWHM) Linewidth: < 6 cm -1 (no étalons) < 2 cm -1 (signal étalon) Pump Signal Idler QS Nd:YV0 4 pump PPLN (Optional étalons) M 2 < 1.4 at 3.3µm Typical Tuning Curve - MWIR Output, Broadband
Firefly-IR + Scanner: Imaging From Firefly-IR MCT Detector CaF2 Lens Galvanometer mirror Raster : Backscatter Absorption Gas Imaging for Gases Active Reflectance / Absorption Imaging of Liquids/Solids
Video-Rate Imaging of Gases Normal video: gas is invisible What Firefly saw – methane gas
Firefly-IR + Scanner: Imaging Applications Demonstration of gas imaging and false colour concentration measurement with Firefly-IR using differential absorption
Firefly-IR + Scanner: Concentration Resolution & range Sensitive CH 4 monitoring Detection to <35 ppm.m Real-time imaging
Identification of Liquids Spectral fingerprinting of liquids : various mineral oils
Identification of Liquids II Spectroscopic & spatial negative contrast imaging of mineral oils – with differential analysis Z ~1.2 m
www.m2lasers.com Imaging Threat Simulants: Forensics : Attempted to remove CWA simulant but still detectable Z ~1.2 m
Applications in Threat Detection / Forensics Identifying threats Security & venue protection Counter Terrorism screening Decontamination Identifying effective decontamination requirements Triage Understanding nature of attack substance Forensic Investigation Ability to investigate a scene remotely and chemically map evidence.
THz Imaging for Drug Detection THz Spectral Fingerprinting The Importance of Terahertz: New spectroscopic area important for molecular identification Like X-rays but non-ionising – not dangerous Drug detection and Identification Leveraging pharmaceuticals non-destructive testing / analysis Leveraging pharmaceuticals non-destructive testing / analysis Ecstasy Aspirin Meth
Summary Demonstrated active IR spatial/spectral detection of gases and liquids Gases down to 10ppm.m at >10m Liquids down to 20ul at 10m Solids down to ng of residue Novel laser sources provides new capabilities for threat agent imaging with potential applications in: Detection of CWAs and Explosive Materials Counter-terrorism and forensic investigation Drug detection and analysis
Your consent to our cookies if you continue to use this website.