Sulfur Near Edge X-ray Fluorescence Spectroscopy Data for standard materials

Sulfur Near Edge X-ray Fluorescence Spectroscopy Data for standard materials

Methodology: The sulfur standards were ground using an agate mortar and pestle to the consistency of a fine talcum powder (approximately 10 um). A cellulose acetate filter was then gently dredged through a small quantity (less than 1 mg) of powder placed on a microscope slide. This procedure produced a thin and almost imperceptible coating on the filter in order to limit the thickness and thus self-absorption. S-NEXFS spectra of sulfate standards were collected in bulk mode. Self-absorption must be carefully controlled when measuring fluorescent X-rays from thick specimens; however, the effects of self-absorption are limited to the region of the spectrum above the K-edge. In our repeated measurements, the post-edge features were consistent and reproducible, which allows discrimination of different sulfate standards.
Sampling and analytical procedures: S compounds and minerals were obtained from chemical supply houses or mineral dealers. See papers cited below for details.
Instruments: X-ray fluorescence microscope located at beamline 2-ID-B at the Advanced Photon Source, Argonne National Laboratory. The beamline is optimized to examine samples over a 1-4 keV energy range using a focused X-ray beam with a spot size of approximately 60 nanometers squared . The energy was calibrated using an elemental sulfur standard. The whiteline energy of the elemental sulfur standard was aligned to 2472 eV.
Data processing: S-NEXFS data were normalized to create a relative intensity value of approximately 1 for post-edge area of the spectra. The data were also processed using a three-point smoothing algorithm built into the software package Athena to remove highfrequency noise (Ravel and Newville, 2005).

Processing Description
BCO-DMO Processing: modified parameter names (replaced spaces with underscores, removed special characters). [
(2016). Composition and oxidation state of sulfur in atmospheric particulate matter.

Microscope-Fluorescence
Datasetspecific Description X-ray fluorescence microscope located at beamline 2-ID-B at the Advanced Photon Source, Argonne National Laboratory: The beamline is optimized to examine samples over a 1-4 keV energy range using a focused X-ray beam with a spot size of approximately 60 nanometers squared . The energy was calibrated using an elemental sulfur standard. The whiteline energy of the elemental sulfur standard was aligned to 2472 eV.

Description
Instruments that generate enlarged images of samples using the phenomena of fluorescence and phosphorescence instead of, or in addition to, reflection and absorption of visible light. Includes conventional and inverted instruments.
[ By defining the relationship between air mass source region, aerosol composition, and bioavailability, results from this work will improve current knowledge of the factors regulating productivity in the Mediterranean Sea and help to clarify the potential response of this region to different climate change scenarios. Broader Impacts: In addition to the valuable insights this project will provide on the controls on productivity and nutrient cycling in the Mediterranean Sea, this study will further education of young scientists, broaden participation of underrepresented groups in ocean science, and enhance research infrastructure. [