Integrating Sphere-Based Nephelometer for UAS Applications

This project will develop a novel, multi-wavelength integrating nephelometer, for use on small aerial platforms; such as UAS, tethered balloons, kites and other space-constrained applications. The main goal is to reduce the size of a typical research grade integrating nephelometer, maintaining its detection limit in the miniaturized device through technology innovation. The proposed nephelometer will use an integrated sphere (or cavity) for homogeneous illumination of the sample volume, combining a very low truncation angle with the ability to multiply the light intensity in the sample volume using the multiple reflection paths of the sphere. American Ecotech plan to implement an approach where the light sources are mounted on the equator of the sphere and test newer materials improving the reflectivity inside the sphere. This way, enough sensitivity gain will be accomplished to further miniaturize the nephelometer making it ideal for UAS and other space-constrained applications. This design approach allows for an easy implementation of multiple wavelength operation to measure scattering Ångström exponents in the same aerosol sample. During Phase 1, a feasibility study will be conducted, utilizing existing LED technology to perform multiple characterization tests on the equator geometry design, which will identify critical design elements and parameters for the instrument. Furthermore, provisions to reduce sampling time, and increase the measurement speed in the miniaturized instrument will be tested as this will further enhance the capabilities for UAS applications and other time critical measurements. Initially these Instruments will benefit greatly the research community as they enable research with better spatial and time resolution as obtainable by satellite measurements, but they will enable many other applications, where fast, accurate, reliable, independent measurements are needed from event monitoring like wildfires to regulatory or exploratory measurements for Plume distribution, Plant emissions, Process surveillance and control etc. Novel compact and sensitive instruments measuring light scattering from microscopic airborne particles (i.e., aerosols) are needed for deployment on small aerial platforms to characterize aerosol influence on air quality, climate change, and visibility degradation. The project aims to develop such instruments based on transformative technological innovation and novel materials.