AN UPDATE TO NRLXRF AND NBSGSC, W.T. Elam and J.R. Sieber, pp. 442-448

The public-domain computer codes NRLXRF, developed at the Naval Research Laboratory (NRL), and NBSGSC, developed at the (then) National Bureau of Standards (NBS), were among the fust and most important early realizations of the fundamental parameters (FP) method of analyzing X-ray fluorescence @RF) spectra. However, it has been 20 years since NRLXRF was updated and more than 10 years since NBSGSC was released. We are attempting to revise and update these codes and combine them into a single, modular package to meet our respective needs for fundamental parameter calculations. The update, as presently planned, will comprise three components. The first is to incorporate the most recently available values for the parameters themselves. The main update will be to the X-ray absorption cross sections using the values of Hubbell and Seltzer [l] at high energies and the values of Herike, Gullikson, and Davis [2] at low energies. Other parameters will be updated as much as possible. The second component is to incorporate improvements in the calculation of excitation spectra from X-ray tubes. Finally, we plan to adapt the codes for multilayer samples using the work of De Boer [3].