This technology includes improvements in the fluorescence scanner to increase efficiency. This method works by eliminating the need to radially slide the optical assembly during scanning, instead using a galvanometric mirror deflecting a laser beam to different positions in the sample. This allows the scanner to be incorporated into existing commercial analytical ultracentrifugation (AUC) systems with minimal modifications. A further improvement designed to increase detection efficiency is the use of plano-convex windows replacing planar windows in the sample cell assembly, which can help focus excitation and emitted fluorescence. Ensuing spatial inhomogeneities of beam angles and excitation intensities and detection efficiencies are accounted for in the mathematical analysis.