Aerosols and Morphology

Wednesday, July 25, 2012 - 3:00pm

Duane Loh, PULSE Institute

Why does soot appear black while its crystalline counterpart, diamond, appear transparent? The answer lies in the varying morphological properties of carbon allotropes. I will discuss how morphology using the x-ray free-electron laser at LCLS showed that individual aerosol soot can have densities that are higher than that predicted by diffusion-limited cluster aggregation models. Such measurements have notable implications on our understanding of the airborne formation and transportation of soot, and its impact on radiative forcing in climate studies. Additionally, measuring the signature of ions produced by individual aerosol particles when subjected to the strong ionizing effect of x-ray laser pulses can also probe the composition of these aerosols.

When the structure of the individual aerosol particles are known well enough, they can in turn be used to study the structure of x-ray laser pulses. In the second part of my talk, I will explore how we can probe the intense focus of free-electron laser pulses using only the ensemble of single-particle diffraction patterns produced when they are intercepted by aerosolized, sub-micron polystyrene spheres.

Aerosols and Morphology
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