Analysis of the single scatter albedo and imaginary index of refraction of fused silica nanospheres via a photoacoustic technique and a novel aerosol generator
AdvisorArnott, Patrick W
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This experiment sought to study the single scatter albedo (SSA) and imaginary index of refraction of 300nm fused silica spheres using the in-situ technique of photoacoustic spectroscopy. Through the use of a novel aerosol generator, sample aerosol streams were generated and sampled via a 4 wavelength photoacoustic spectrometer system. The measured SSA was used to calculated a value for the imaginary index of refraction for aerosols containing solutions of water and glass beads, water and salt, pure isopropanol, pure methanol, methanol and beads, and methanol and salt.The average SSA for glass beads was found to be 0.9976 (+/- 0.0001) at 405nm, 0.9962 (+/- 0.0008) at 532nm, 0.9962 (+/- 0.0003) at 870nm, and 0.9921 (+/- 0.001) at 1047nm corresponding to an imaginary index of refraction on the order of 〖10〗^(-4), three orders of magnitude higher than reported values for bulk fused silica. SEM imagery shows large concentrations of particle agglomerates and dissolved solids in the carrier medium which likely contributed to a higher absorption signal.