Browsing by Author "Maconi, Göran Konstantin"

Light scattering measurements are important for characterizing small particles. The scattering data can replace simplified theoretical models in simulations, e.g. Mie scattering, providing significantly more realistic simulation results. It can also be used as a standard, to which more advanced scattering models can be compared. We present a new instrument for measuring light scattered by micrometer- to millimeter-sized particulate samples, which are levitated ultrasonically. The instrument was built within the scope of this project. While other setups exist that can measure light scattering, our instrument is unique in its capability to measure individual particles which are held in place in mid-air. The system is measures light of multiple wavelengths, scattered in 360 degrees and taking light polarization into account. Samples are held in place by a Langevin-type ultrasonic levitator, which eliminates any stray scattering from a sample holder, while simultaneously making the measurement non-destructive and non-contacting. The non-destructive measurement allows for research on valuable and unique samples, such as rare meteorites and space dust. In this work, we detail the design principles of our instrument, as well as its calibration. We estimate its performance by measuring scattering from clear glass spheres and comparing the results to Mie scattering simulations. We also demonstrate the instrument's capability to handle real samples by measuring the light scattering properties of a rock sample taken from the Chelyabinsk meteorite. The measurements show that our instrument provides accurate light scattering data from a variety of samples. This makes it a valuable tool which can be used to validate theoretical models and provide unique light scattering data from samples that would otherwise be hard to measure.