Proposal: Let's Develop a Community Consensus K-ratio Database

Electron probe microanalysis (EPMA), whether by wavelength-dispersive spectrometer or energy dispersive spectrometer, is a method for measuring the composition of a material. However, EPMA is an indirect technique. The fundamental measurand in EPMA is the X-ray intensity. Materials are compared through the ratio of X-ray intensities measured under similar conditions on the unknown and a standard – called the k-ratio. The k-ratio is converted to a measure of composition through an implicit multivariate measurement model [1], called matrix correction, in which we compute the anticipated k-ratio for a specified element and X-ray line in a specified material and compare it with the measured k-ratio. The estimated composition is adjusted through a non-linear optimization process, called iteration, until the computed k-ratio equals the measured k-ratio.