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Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of Ocean Worlds

Presentation #001.06 in the session “Future Missions, Instruments, and Facilities”.

Published onOct 26, 2020
Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of Ocean Worlds

One of highest priority science objectives for astrobiology is to characterize habitability and detect signatures of life in the solar system. The development of new, compact, and energy-efficient technologies capable of facilitating that objective is necessary for surface exploration of Ocean Worlds and other planetary bodies. The habitable potential of the ocean beneath the icy shell of Europa has been inferred by geophysical geothermal features, indicating the presence of brines and materials conducive to life macromolecular organics, and organic-enriched ice grains have been detected in ejected plume material on Enceladus. Raman spectroscopy has established itself in current missions as an information-rich, non-contact, non-destructive method for identifying and characterizing inorganic and organic compounds and characterizing structural features in a wide variety of planetary materials. Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of Ocean Worlds enables the identification of minerals, volatiles, organic molecules, biopolymers, water, and other hydrous phases in planetary materials. UV-DIRECT utilizes a silicon-carbide (SiC) avalanche photodiode (APD), with high internal gain, specifically targeted for the identification of ocean world-relevant compounds utilizing UV/NUV (266-340 nm) Raman spectroscopy with ppb sensitivity. Excitation in the UV range permits the acquisition of Raman spectra without the signal-interfering fluorescence that is typical under longer excitation wavelengths. SiC detectors are radiation hard and are also “blind” to visible light, i.e., solar background, that can completely obscure the Raman signal. Unlike most mission-relevant Raman detectors that only support the acquisition of point spectra, the architecture of UV-DIRECT enables Raman spectroscopic imaging. Acquiring point spectra can provide information about what compounds are present; Raman imaging enables the full characterization of target areas revealing spatial relationships between compounds, improving the capability of detecting biosignatures. For life detection this is important because while abundant in the solar system, the mere presence of organics does not indicate life, but the complexity of that material may be a biosignature. The SiC APD technology in UV-DIRECT is applicable for stand-off or in situ Raman applications, enabling compact, robust instrumentation for planetary surface exploration using Raman spectroscopy.

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