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Multi-Angle Light Scattering
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"Development of a Multi-Angle Light Scattering Spectrometer for Aircraft Use",
William Dick, Keung Woo, Mihai Chiruta, Francisco Romay, MSP Corporation
A system that provides direct measurements of key properties needed for inversion
of data from satellite-borne remote sensors & ground-based LIDAR systems for aerosol characterization
over a large geographical area. Intersection of the aircraft flight path with the satellite path at the same
point in time allows direct correlation of multiangle light scattering data and remote-sensing data.
"The Quest for Detection and Identification of Bio-aerosols",
Richard K. Chang, Gustavo E. Fernandes, Yong-Le Pan, Kevin Aptowicz, Ronald G. Pinnick, Progress In Electromagnetics Research Symposium 2007, Beijing, China, March 26-30
A brief review is made of the status of fluorescence techniques to detect and partially
identify bio-aerosols. The potential and frustrations in extracting morphology information
from the angularly-resolved elastic scattering pattern is summarized. The latest advancements in
the measurement of angularly-resolved elastic-light scattering for single aerosol particles on-the-fly
are surveyed. Special emphasis is placed on our more recent efforts to simultaneously measure
the scattering patterns of aerosol particles in both the forward and backward hemispheres.
"An Instrument for the Simultaneous Acquisition of Size, Shape, and Spectral Fluorescence Data from Single Aerosol Particles",
Edwin Hirst, Paul H. Kaye, Virginia Foot, James M. Clark, Philip B. Withers, Proceedings of SPIE -- Volume 5617
Optically Based Biological and Chemical Sensing for Defence, December 2004, pp. 416-423
Copyright ©2005 SPIE--The International Society for Optical Engineering
We describe the construction of a bio-aerosol monitor designed to capture and record intrinsic
fluorescence spectra from individual aerosol particles carried in a sample airflow and to simultaneously capture
data relating to the spatial distribution of elastically scattered light from each particle. The spectral fluorescence
data recorded by this PFAS (Particle Fluorescence and Shape) monitor contains information relating to the particle material
content and specifically to possible biological fluorophores. The spatial scattering data from PFAS yields information
relating to particle size and shape. The combination of these data can provide a means of aiding the discrimination of
bio-aerosols from background or interferent aerosol particles which may have similar fluorescence properties but exhibit
shapes and/or sizes not normally associated with biological particles. The radiation used both to excite particle
fluorescence and generate the necessary spatially scattered light flux is provided by a novel compact UV fiber laser
operating at 266nm wavelength. Particles drawn from the ambient environment traverse the laser beam in single file.
Intrinsic particle fluorescence in the range 300-570nm is collected via an ellipsoidal concentrator into a concave grating
spectrometer, the spectral data being recorded using a 16-anode linear array photomultiplier detector. Simultaneously,
the spatial radiation pattern scattered by the particle over 5°-30° scattering angle and 360° of azimuth is recorded
using a custom designed 31-pixel radial hybrid photodiode array. Data from up to ~5,000 particles per second may be
acquired for analysis, usually performed by artificial neural network classification.
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