2.1. Energy Dispersive X-ray Diffraction (EDXRD)

The EDXRD diffractometer is home-assembled equipment that is used in the Energy Dispersive X-ray Diffraction technique. It consists of white X-ray radiation produced by a commercial W-anode X-ray tube (up to 50 keV) and a solid-state detector, in our case, an EG&G high purity Germanium photodiode, with an energy resolution of approximately 1.5–2.0% in the 20–50 keV energy range with the capability to perform an energy scan. The ADCAM hardware connects the detector to a PC, and Maestro software processes the signal and completes the required analog to digital conversions. The energy scan is carried out electronically, and diffraction patterns represent the diffracted intensity (n° of incident X-photons) as a function of the scattering parameter q (q = aE sinϑ), where q is the normalized momentum transfer magnitude, a is a constant, E is the incident X-ray beam energy, and 2ϑ is the scattering angle). As preliminary experiments to determine the optimal experimental conditions, ex situ diffraction patterns were recorded for powder samples at different scattering angles. All the measurements were performed with a white primary beam with energy ranging from 0 to 50 KeV and with a current intensity of 30 mA. Based on previous experience, we found that the best scattering angle is around 2θ = 10°. Peaks at around 2θ = 10° are the fluorescence signals of the W anode X-ray tube used as a radiation source of the diffraction apparatus. Those peaks are registered at around 8.5 KeV (W Lα) and 9.5 KeV (W Lβ), and upon conversion, they are reported (in this specific case) at around 2θ = 10°. As for the Ba fluorescence peaks, they are considered not relevant for the diffraction analysis and therefore are not discussed. The difference in relative intensities can be attributed to different scattering angles acquisition and normalization processes of the EDXRD patterns.