Electron microprobe (EMP), also known as electron probe microanalyzer (EPMA), is an analytical tool designed to rapidly determine the chemical composition of solid-state materials at very small spatial scales (areas ≥1 micron or 1/1,000,000 of a meter). EPMA utilizes a focused beam of high-energy electrons to excite X-rays characteristic of the individual elements within a solid material. The instrument can quantitatively measure the concentrations of all elements from atomic number 4 (Be) to 92 (U), some at detection limits less than 10 parts per million (ppm). EPMA has a broad range of scientific applications and is used in a variety of fields including geology, biology, archeology, material science, chemical, mechanical and biomedical engineering, physical and biological chemistry, solid-state physics, metallurgy, and electronics.

The Electron Microprobe Laboratory at the University of Iowa is located in the Department of Earth and Environmental Sciences, and was established in 2014 through a National Science Foundation Major Research Instrumentation award. It features a state-of-the-art JEOL JXA-8230 Superprobe equipped with 5 wavelength-dispersive spectrometers and 8 large-format diffracting crystals- LDE1L (1); TAPL (1); PETL (3); LIFL (3). This allows for the quantification of elemental concentrations at the single ppm level (i.e. <10 ppm). The JXA-8230 is also equipped with back-scattered electron (BSE), secondary electron (SE), and cathodoluminescence (CL) detectors for high-resolution imaging, and an energy-dispersive spectrometer (EDS) for rapid semi-quantitative analyses.

The University of Iowa Electron Microprobe Laboratory is also equipped with a brand new Nikon Eclipse Ci POL polarizing microscope outfitted with a high-definition Nikon DS-Fi2 digital camera, an Olympus SZX7 stereomicroscope, and a top-of-the-line Cressington 208C high vacuum carbon coater with a tilting rotary stage, high-resolution thickness monitor, and metal evaporating capabilities. The laboratory is overseen jointly with the University of Iowa’s Central Microscopy Research Facility and has a professional staff with extensive experience working with both academic and industry clientele. We perform quality control evaluations on every dataset that our laboratory produces and take great pride in producing the highest quality electron microprobe data available.