Neutron diffraction provides a direct probe for the ordering of spins from unpaired electrons in materials with magnetic properties. The ordering of the spins can be modeled in many cases by adding spin directions to standard crystallographic models. This requires, however, that crystallographic space groups be extended by addition of a “color” attribute to symmetry operations, which determines if the operation maintains or flips the direction of a magnetic spin. Rietveld analysis provides a mechanism for fitting magnetic structure models to powder diffraction data. The general structure and analysis system (GSAS) software suite is commonly used for Rietveld analysis and includes the ability to compute magnetic scattering. Different approaches are commonly used within GSAS to create models that include magnetism. Three equivalent but different approaches are presented to provide a tutorial on how magnetic scattering data may be modeled using differing treatment of symmetry. Also discussed is how magnetic models may be visualized. The commands used to run the GSAS programs are summarized within, but are shown in great detail in supplementary web pages.

One of the main threats to human health from heavy metals is associated with the exposure to lead (Pb). In vivo X-ray fluorescence analysis (XRF) of human bone is a widely used technique to determine the total Pb body burden. The intention of this work was to study the feasibility of in vivo L-shell XRF measurements of Pb in bone using X-ray tubes as excitation sources. Parameter studies using direct tube excitation with various anode materials (Mo and W) and filters as well as different secondary targets and low-Z polarizers were performed with regard to the lowest limits of detection (LLD) achievable for Pb in bone matrix. A breakthrough for the development of a portable spectrometer was achieved by using an air-cooled low-power (50 W) Pd anode X-ray tube, Mo secondary target, and a Peltier-cooled silicon drift detector. LLDs for Pb in bone were determined from measurements on a plaster-of-paris standard without overlying tissue equivalent material and found to be around 0.6 μg∕g.

Rapid and accurate methods are becoming available to calculate all of the relevant physical effects that contribute to an energy-dispersive X-ray fluorescence (EDXRF) spectrum, rather than just the characteristic line intensities given by the traditional fundamental parameters method. To evaluate the utility of such methods, we have calculated the full spectra of several compounds covering a wide range of compositions. The calculated spectra are compared directly with measured spectra. They include scattering of the X-ray tube lines and continuum, the Compton profile, and the detector response. Our results indicate that it is now possible to compute the full spectrum from an EDXRF system with very good accuracy.

Low energy characteristic X-ray emission from Al2O3 monocrystalline specimens is measured under bombardment of 100 keV Xe+ ions. The electric field influence on emission of the X-rays of constitute elements in the specimens was investigated. The energy dispersive X-ray spectroscopy spectra show that the characteristic X-ray of Al-Kα seems to be depressed by the applied dc voltages, while the peak intensity of O-Kα was not notably influenced. The O-Kα peaks were broadened and the total counts increased as a higher dc bias was applied. It is possible that a dc electric field parallel to the target surface may influence the X-ray emission from it under ion bombardment.