NIST DTSA-II has recently been updated to version Iona. (Download for free from http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html (http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html)) DTSA-II provides a host of tools for quantitative EDS microanalysis including quantification, simulation and measurement planning. Iona has a host of improvements both large and small which are detailed in the release notes on the web site.
Further details on quantitative analysis with NIST DTSA-II are available in Newbury & Ritchie's J. Mat Sc. Article "Performing elemental microanalysis with high accuracy and high precision by scanning electron microscopy/silicon drift detector energy-dispersive X-ray spectrometry (SEM/SDD-EDS)" (free for download from http://link.springer.com/article/10.1007/s10853-014-8685-2 (http://link.springer.com/article/10.1007/s10853-014-8685-2) ). This article demonstrates the potential of the modern EDS detector to perform reliable, quantitatively accurate compositional measurements even for some very challenging samples.