Multi-Angle, Multi-Wavelength Scattering Diagnostic for Characterization of Dense Liquid Aerosol Sprays

Characterization of liquid aerosol droplets in agent defeat scenarios presents enormous challenges, in part due to high optical density conditions in sprays generated from shock or fragment interactions with liquid-filled containers.  We propose a new diagnostic that can probe optically dense regions, based on optical scattering of laser light from particles/droplets.  Our diagnostic instrument will measure the angular distribution of light scattered from particles, combined with models of optical scattering to determine the particle size distribution inside the sprays.  In addition to measurement of multiple angles simultaneously, the instrument will use multiple wavelengths from the visible to the long-wave infrared to increase the range of particle sizes, which can be measured with high sensitivity.  Long-wave infrared lasers will be used for discrimination of agent simulant from non-simulant particles and to determine aerosolized mass fraction.  Semiconductor laser sources combined with high-speed modulation and detection will provide high sensitivity and dynamic range for measuring dynamic changes in spray evolution.  The diagnostic instrument will operate in a standoff configuration with scalable range, for probing conditions near explosive/fragmentation zones.