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Engineered for LifeITT IndustriesITT Industries Advanced Engineering
& Sciences Division
Development of Eye-Safe Lidar Technologyfor Aerosol and Cloud Measurements
Scott HigdonITT Advanced Engineering & Sciences Division
Lasers and Electromagnetics DepartmentAlbuquerque, NM
USEPA ORS WorkshopJuly 30, 2002
Scott HigdonPh: (505)889-7006scott.higdon@itt.com
Engineered for LifeITT IndustriesITT Industries Advanced Engineering
& Sciences Division
Presentation Outline
• Lidar Overview
• Eye-Safe Lidar for Atmospheric Aerosols
• Differential Scattering Lidar for Bio-Agent Detection
• Laser Interrogation of Surface Agents (LISA)
Radar = Radio Detection and Ranging
AmplifierA-D Converter
orPhoton Counter
Computer
Data Storage
Lidar = Light Detection and Ranging
Aerosols
Molecules
Engineered for LifeITT IndustriesITT Industries Advanced Engineering
& Sciences Division
Engineered for LifeITT IndustriesITT Industries Advanced Engineering
& Sciences Division
ITT Lidar Measurement Techniques
ElasticBackscatter
LaserRaman
Scattering
DifferentialAbsorption
Lidar(DIAL)
1.0x10 6
0.8
0.6
0.4
0.2
0.030002500200015001000500
Raman shift (cm -1)
DIMP
1-50 km
1-50 m
1-15 kmRange Resolved
orPath IntegratedMeasurements
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ITT Lidar Technology Program
Chemical and Biological Agent Detection Atmospheric & EnvironmentalLidar Sensors
Ground-BasedDifferentialAbsorption
Lidar
The ITT lidar team develops and fields operational lidarsensors for chem/bio warfare agent detection and for
atmospheric and environmental measurements.
Standoff Detection of SurfaceDeposited Chemical Weapon Agents
Standoff Detection ofBiological Weapon Agents
Airborne Detection of VaporPhase Chemical Weapon Agents
AirborneDifferentialAbsorption
Lidar
Raman Lidar
DifferentialScattering
Engineered for LifeITT IndustriesITT Industries Advanced Engineering
& Sciences Division
Eye-Safe Lidar forAtmospheric Aerosols
Engineered for LifeITT IndustriesITT Industries Advanced Engineering
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AEROSOLPARTICLES
FOSSIL FUEL COMBUSTION
SO2
GROUND BASED LIDARMEASUREMENTSNATURAL SOURCES
TRANSPORTMIXINGREACTION
EFFECT ON EARTH’STEMPERATURE
Natural Sources: windblown dust, sea spray, volcanoes, gas-to-particle conversion; etc.
Anthropogenic Sources: fuel combustion, material processing (eg.crushing, grinding),intentional release of biological agent aerosols
Atmospheric Aerosol Sources
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0 1000 2000 3000 4000 5000 6000 7000
2000
1000
0Range (meters)
Barcelona
26jul323d; 17:42 hrs, 35 deg
Altitude(meters)
Mix Layer
StableResidualLayers
0 1000 2000 3000 4000 5000 6000 7000 8000Range (meters)
3500
3000
2500
2000
1500
1000
500
0
r2 Corrected Data
8.0 14 20 26 32
Mexico CityAltitude(meters) PBL and
Mix LayerHeight
Entrainment Zone
ConvectionCell
IndustrialPlumes
Highway
Examples of Aerosol Lidar Measurements
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& Sciences Division
Hampton University Eye-safe Aerosol System
Center for Lidar and Atmospheric Sciences Students
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& Sciences Division
For the same operating parameters, a 1.5 m laser is~105 times safer than 1.064 m laser~200 times safer than 0.355 m laser
0 1 2 3 4 51 10 3
0.01
0.1
1
10
100
1 103
1 104M
axim
um E
yesa
fe E
nerg
y (m
J)
Q1 a( )
Q2 a( )
Q3 a( )
a
cm
Max Eyesafe Energy vs. Beam Diameter, a, at Laser Output
Beam diameter at laser output aperture
1064 nm
355 nm
1500 nm
Eye Safety Considerations
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Eye-Safe Near-IR Transmitter
Nd:YAG Output(14 Hz)
320 mJ
After Isolator 290 mJ
OPO Output 82 mJ
OPO Energy Stability(/mean)
2%
Nd:YAG Divergence(Full Angle)M2
0.43 x 0.80 mrad
3 x 6OPO Divergence(Full Angle)M2
4.8 x 5.8 mrad
12 x 23
• Operation at 20 Hz yielded unusually high divergence for Nd:YAG and OPO.
• Nd:YAG reconfigured for lower PRF operation.
• Present tests underway to fully characterize effects of pump divergence and PRF
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Receiver Optics
Lightweight Telescope Mirror
Transceiver Housing
Receiver Optical Design
Lens/Filter Subassembly
Lens 1
InGaAsAPD
Filter
Lens 2
Lens 3
10” CatadioptricTelescope
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CLASS Lidar Team at Hampton University
Center for Lidar and Atmospheric Sciences Students
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Atmospheric and Hard Target Return Signals
Near Field Return Far Field Return
(Sandia Mountains)
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(A) (B)
Scanning Lidar Backscatter Signal After Background Subtraction and Range Correction(A) Jan-02-2002, Hampton, USA, azimuthal scanning of a cloud with 70 degrees elevation angle,
(B) Jan-02-2002, Hampton, USA, elevation scanning of a cloud
Cloud Measurements
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Micro-Pulse Lidar (MPL) Technology
• Pioneered by NASA Goddard Space Flight Center
• Uses high rep rate (1-10 kHz)/low pulse energy (10-50 J)at 532 nm to achieve eye-safe output at the aperture
• Low-cost, reliable, autonomous operation
• Requires long time averages and not conducive to scanning
• NASA GSFC is developing a network of these lidars (MPL-Net)at various locations around the world
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Remote Detection ofBio-Agent Aerosols
DifferentialScattering
Lidar
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Transmitter for Bio-Agent Detection Using Differential Scattering Lidar
m OPO
Nd: YAG
3.4-3.7
OC HRType III
KTA
>100 mJ1.5 m
1.5 m OPO
OC HRType III
KTA
>50 mJ3.4 - 3.7
375 mJ 1064 nm20 HZ rep-rate
350 mJ1064 nm
Isolator
PockelsCell
Polarizer350 mJ1064 nm
ITT is developing a DISC lidar system using this transmitter forthe ARMY SBCCOM in collaboration with Physical Sciences, Inc.
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Dual Transmitter
Receiver Aft Optics
PrimaryMirror
TransmitterSection
Receiver AftOptics Section
14”
42”
26”
Transceiver Module
Bio-Agent Lidar System Transceiver Design
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Bio-Agent Lidar System
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Laser Interrogation ofSurface Agents (LISA)
NBCRS - Fox
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SiliconSampleWheel
SiliconSampleWheel
MassSpectrometer
Probe
• Requires sample collection using a surface-contact mechanical device
• Requires a dedicated device operator• Slow response and very small sampling area• Operational and supply logistics issues
Current Approach for Ground Contamination NBCRS Fox Vehicle Sample Wheel Device
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Measurement Methodology:Raman Scattering
• Vibrational Raman Scattering occurswhen light interacts with a molecule
• A small amount of wavelength-shiftedlight is scattered
• Amount/intensity depends on the molecule’s size, shape, and strength(vibrational modes of the molecule)
• Creates a distinct “spectral fingerprint”
Selectivity is the hallmark of Raman spectroscopy
Selectivity is the hallmark of Raman spectroscopy
Laser Light
Molecule
RayleighScattering
RamanScattering
VibrationalModes
-0.025
0.075
0.175
0.275
0.375
0.475
0.575
0.675
0.775
3500 3000 2500 2000 1500 1000 500 0
Raman Shift (cm-1)
p-xylene
o-xylene
m-xylene
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LISA Concept
Dispersive Optics
Telescope
Illumination
Molecules of Chemical Agent
Chemical Fingerprint
Molecules of Chemical Agent
Scattering
Raman Signal
Photo-Detector
DatabaseAlgorithms
Analysis
id
Detection &Identification
Fiber Bundle
Laser Transmitter LISALaser Interrogationof Surface Agents
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BNL Mini-Raman Lidar System (MRLS) uses laboratory off-the-shelf components
1.0x106
0.8
0.6
0.4
0.2
0.0
Coun
ts
30002500200015001000500Raman shift (cm
-1)
1.2x106
1.0
0.8
0.6
0.4
0.2
0.0
Coun
ts
30002500200015001000500Raman shift (cm
-1)1.0x10
6
0.8
0.6
0.4
0.2
0.0
Coun
ts
30002500200015001000500Raman shift (cm
-1)
TMP
DMMP
DIMP
MRLS measured spectral signatures& distinguished related compounds
MRLS Sensitivity 2 g/m2 (single shot at 1 m)Military requirement 0.5 g/m2
LISA Proof-of-Concept: MRLS
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ITT LISA-Recon System
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Preparation for Field Measurements
HMMWV Test Vehicle Sensor Module & Vibration Mount
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Single Shot Measurements & Identification
10002000300040005000Raman shift cm-1
1
2
3
4
5
6x104
Cou
nts
(Bg
Cor
rect
ed)
10002000300040005000Raman shift cm-1
3.1
3.3
3.5
x104
Cou
nts
01000200030004000Raman shift cm-1
2
4
6
x104
Co
un
ts (
Bg
Co
rrec
ted
)
Teflon sheet
(single shot)
Atmospheric O2 and N2
Superimposed on featureless sand
(100 shot average)
Cyclohexane
(single shot)
•Cyclohexane and Teflon are materials used by BNL to characterize their system.
•We can use them to compare our system performance to the baseline BNL system
•The O2 & N2 signature forms the kernel of an instrument confidence check
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Initial Single Shot Measurements ofa Chemical Agent Simulant
•Red curve: single shot measurement of MeS at 0.25 g/m2 with 9.1 mJ laser pulse.
•Spectra for the atmosphere, water and the quartz vial (2 mm path length) are removed.
•SNR of the MeS peak near 1610 cm-1 is approximately 15.
•Blue curve: same but 100 shot average, 15 mJ pulse.
0 500 1000 1500 2000 2500 30000
2000
4000
6000
8000
Raman shift (cm-1)
Ram
an re
turn
(dig
itize
r cou
nts)
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ESTCP Project
Application of (LISA) Technology to DoD EnvironmentalSite Characterization Requirements
Develop innovative, rapid screening technologies to detect and delineate land areas with soils containing contaminants associated with live fire training activities including energetic compounds (RDX, HMX, TNT, DNT), propellants, and their byproducts.
Dr. Steve Christesen – Army ECBCMr. Scott Higdon – ITT IndustriesDr. Arthur Sedlacek – BNLMs. Tamera Rush - AECDr. Daniel Powell – EPA (Advisor)
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UV Detection of Explosives
TNT data showing the advantagesof UV (< 253 nm) excitation
TNT data showing the advantagesof UV (< 253 nm) excitation
Raman spectra of TNT and 4NT can bedistinguished by the strong peak at 860 cm-1
Raman spectra of TNT and 4NT can bedistinguished by the strong peak at 860 cm-1
UV excitation provides:1. Reduced fluorescence2. Potential for simplified spectra and
Raman scattering enhancement (103
to 106) from resonance Raman effect
Data from Lacey, et al., Characterizationand Identification of Contraband UsingUV Resonant Raman Spectroscopy, SPIEVol. 2937, 100 – 104, 1997.
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Mission Applications• Reconnaissance vehicles• Cargo inspection• Shipboard sensor• Homeland Defense• Environmental cleanup• Planetary exploration
Potential Users• Army SBCCOM• FAA/TSA• Navy• Civil Support Teams• EPA• NASA
LISA technology provides a unique solution to the very challengingproblem of detecting and identifying surface-deposited chemicals
LISA Future Missions
LISALaser Interrogation ofSurface Agents
Advanced Engineering& Sciences
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