Correction for specimen movement after acquisition of element-specific electron microprobe images

Abstract
Because a long time is generally required to generate X-ray maps of specific elements by electron beam methods, images are subject to a loss of resolution due to stage movement. Methods have been previously described for correcting stage drift during exposure by sensing the drift and deflecting the beam to follow the stage; but these methods require modifications of the equipment. When the drift is not excessive, it is possible to correct a series of images after the exposure series is finished. Here we demonstrate two methods for correcting the drift, one based on manual assignment of specimen position and one on the use of cross-correlation functions to determine objectively the misalignment of images in the series. The success of the methods is illustrated in calcium-specific images of a bone section that show the collagen periodicity after drift correction.