Modeling background level of XRD peak profle for the variance method of size‑strain analysis

Abstract

A modifed version of the Enzo-Parrish method is introduced, which success fully determines a straight background level with a nonzero gradient. The mod eled “true” background levels obtained using both the Enzo-Parrish and modi fed Enzo-Parrish methods are compared with those obtained using the central moment method. This study proposes a method that uses a scatering vector, S = 2cosθ0sin(θ−θ0)/λ, where 2θ0 is the centroid, 2θ is Bragg (scatering) angle, and λ is the wavelength of the X-ray. The proposed method determines the back ground from the slope of the linear portion of a plot of I(S)S2 versus S2 , where I(S) is the intensity. To the best of the author’s knowledge, this is the frst time that this method has been used to model and subtract the background level for the vari ance method of size-strain analysis. The modifed Enzo-Parrish method enables modeling and subtracting the background level of an XRD peak of a polymer sample. The accuracy of the method is evaluated based on the linear change of the variance-range curve of the XRD peak of a polymer sample.