Abstract: In the calibration and alignment of an X-ray reflectometry (“XRR”) system for measuring thin films, an approach is presented for accurately determining C0 for each sample placement and for finding the incident X-ray intensity corresponding to each pixel of a detector array and thus permitting an amplitude calibration of the reflectometer system. Another approach involves aligning an angle-resolved X-ray reflectometer using a focusing optic, such as a Johansson crystal. Another approach relates to validating the focusing optic. Another approach relates to the alignment of the focusing optic with the X-ray source. Another approach concerns the correction of measurements errors caused by the tilt or slope of the sample. Yet another approach concerns the calibration of the vertical position of the sample.

Abstract: An improved method of making a series of bead or microsphere or particle populations characterized by subtle variation in a proportion or ratio of at least two fluorescent dyes distributed within a single bead of each population is provided. These beads, when excited by a single excitation light source are capable of giving off several fluorescent signals simultaneously. A set containing as many as 64 distinct populations of multicolored, fluorescent beads is provided and when combined with analytical reagents bound to the surface of such beads is extremely useful for multiplexed analysis of a plurality of analytes in a single sample. Thus, methods of staining polymeric particles, the particles themselves, and methods of using such particles are claimed.