Equipment: Acquisition of an energy dispersive x-ray spectroscopy system for use in undergraduate STEM education

Angelo State University, San Angelo TX

Investigators

Abstract

With support from the Improving Undergraduate STEM Education: Hispanic-Serving Institutions (HSI Program), this Educational Instrumentation (EI) project aims to support an energy dispersive x-ray spectroscopy (EDS) and an electron backscatter diffraction (EBSD) system that will be added to our existing scanning electron microscope for use in teaching undergraduate STEM courses and laboratories. EDS is an analytical technique used to determine the elemental compositions of samples by bombarding them with electrons and studying the resultant characteristic X-rays, and the EBSD is a technique used to analyze the grain structure and orientation of samples at the microscale. These systems will be used in chemistry, geoscience, and physics classes for analytical purposes and to help demonstrate the fundamental physical processes involved in X-ray emission. The acquisition of the EDS and EBSD systems will allow students to gain hands-on experience using advanced analytical techniques in both lower- and upper-division STEM courses and labs, and it will also provide undergraduate students with the instrumentation necessary to carry out course-based research projects on campus. An estimated 400 students will benefit from the purchase of this equipment over the two-year project period. In chemistry courses, the EDS system will give both lower- and upper-level students experience with spectroscopy involving core-shell electrons, which is lacking in the current curriculum. In lower-level courses, students will collect spectra of various samples and use those data to identify the composition of the samples. Students in upper-level chemistry courses will be trained in the use of the EDS system and will learn sample preparation, data analysis, and how to effectively communicate their results. In addition, chemistry students will be able to use the EDS system in research projects, including analysis of the components of ion batteries which don’t use lithium to help determine ion load and capacity. The EDS and EBSD systems will be used in lower-level geoscience classes to collect spectra using mineral samples as an introduction to modern analytical techniques and to help students understand how EDS and EBSD systems (and scanning electron microscopes) function. In upper-level geoscience courses, students will learn how to calculate the chemical formula of a mineral based on weight percent oxides and evaluate the extent of solid solution between end member compositions (forsterite and fayalite olivine) using data collected with the EDS and EBSD systems. In physics classes, students will gain experience using X-ray spectra to determine the elemental compositions of various samples, while also observing direct evidence of the quantization of atomic energies. Physics students will also use the EDS system to work on research projects investigating the bremsstrahlung spectra produced using insulating samples. These experiences will advance students’ understanding of the science related to EDS and EBSD and increase their competitiveness in applying to graduate school or for employment in a scientific field. The HSI Program aims to enhance undergraduate STEM education and build capacity at HSIs. Projects supported by the HSI Program will also generate new knowledge on how to achieve these aims. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.