The CARNAÚBA beamline is the tender-to-hard X-ray (2 – 15 keV) scanning nanoprobe planned for the 4^th generation storage ring SIRIUS at the LNLS. CARNAÚBA uses an undulator source with vertical linear polarization in a low-beta straight section and grazing incidence-focusing mirrors to create a nanoprobe at 143 m from the source. The beamline optic is based on KB mirrors and provides high brilliance at an achromatic focal spot down to the diffraction limit diameter of ~30 nm with a working distance of ~6 cm. These characteristics are crucial for studying nanometric samples in experiments involving complex stages and environments. The CARNAÚBA beamline aims to perform raster scans using x-ray fluorescence, x-ray absorption spectroscopy, x-ray diffraction and coherent x-ray imaging techniques. Computed tomography will extend these methods to three dimensions.

Rapidly prepared SrS:Eu ²⁺ ,RE ³⁺ exhibits long red persistent luminescence independent of the rare earth co-dopant due to a high Schottky defect concentration.

The influence of lithium excess and calcination temperature on the luminescence properties of the LiAl₅O₈:Eu under VUV excitation was investigated. The presence of both broad bands and sharp peaks in the VUV and X-ray emission spectra suggests the presence of Eu²⁺, even in absence of reducing atmosphere in the synthesis. The VUV excitation spectra indicated a band gap of 8.5 eV while the UV excited one showed the Eu³⁺ charge transfer transition starting at 3.9 eV. These values indicate that Eu²⁺ is stable in this host since its ground state is below the Fermi level of the host (ca. 4.1 eV). The relation between the intensity of Eu²⁺ and Eu³⁺ emissions showed that the reduction is favored at higher temperatures and lower Li content, leading to the proposition of a reduction mechanism based on the incorporation of charge compensation defects formed in the aliovalent doping of Eu³⁺ in Li⁺ sites.