Observations of Elastic Angular Scattering from Oriented Single Cylinders

Abstract

Elastic scattering measurements and observations have been made on single cylindrical particles suspended in an electrodynamic trap. Under certain circumstances the particles could be maintained in a stationary position and orientation, and scattered light intensities from a He-Ne laser were obtained as a function of angle. The particles were made by cutting and breaking glass wool fibers which were then sorted by filtering. Suspended particles were cylinders approximately 7 micrometers in diameter with aspect ratios from 2 to 20. Photomicrographs were taken to determine the particle size, quality of the cylinder ends, and the extent of small dust or debri attached to the particle surface. Angular scattering patterns of the longer cylinders resembled the “infinite” cylinder case obtained by scattering from a macroscopic fiber. Minor differences observed in the shortest cylinders included a “broadening” of the cone of scattered radiation which increases with decreasing scattering angle, and a higher rate of intensity fall-off as a function of scattering angle.