New Mexico Geological Society Annual Spring Meeting — Abstracts

The acquisition of a new JEOL iHP200F electron probe microanalyzer (EPMA) at New Mexico Tech represents a significant advancement in analytical capabilities for geoscience and materials research. Funded through a Major Research Instrumentation award from the National Science Foundation, the instrument has replaced the aging Cameca SX100 microprobe, enabling higher precision, faster analytical throughput, and expanded research applications. The newly installed EPMA features a state-of-the-art system with backscatter electron (BSE) and secondary electron (SE) detectors, five wavelength-dispersive spectrometers (WDS), an energy-dispersive spectrometer (EDS), and panchromatic cathodoluminescence (CL).

EPMA is an essential tool for micro-scale imaging and chemical analysis of any solid, natural, or synthetic material with elemental compositions from B to U. The new system has the flexibility to increase analytical throughput when needed, utilizing the 5 WDS spectrometers for minor and trace element analysis and the EDS for the major cation determination (e.g., Si and Al). Coupling this new configuration with Mean Atomic Number (MAN) background measurements, we have effectively cut analytical time in half (from 4+ minutes to <120 seconds for major rock-forming minerals). The WDS crystal configuration was specifically chosen to enhance trace-element detection. WDS spectrometers can be “stacked” (analyzing the same element on multiple spectrometers simultaneously) to increase counting statistics with the capability to analyze trace elements down to 10’s of ppm. This improvement is particularly important for critical mineral research and the characterization of rare-earth-element-bearing minerals, which are increasingly important for modern technologies.

Probe for EPMA is 3rd-party software purchased with the new microprobe to help with our data collection and reduction. This high-powered software is widely used in most EPMA labs worldwide. It can produce high-resolution, background-corrected element-composition maps. Essentially, turning each pixel of the map into a standardized geochemical determination, allowing for high-resolution mineral composition and chemical zonation maps to be produced overnight.

In the past, nearly 60% of all users of the NMT microprobe have been student researchers from NMT, other NM universities, or adjacent states, providing invaluable training and exposure to microbeam analysis. The new state-of-the-art microprobe will play a vital role in education and workforce development at NMT. It will continue to support student training through hands-on courses and research projects, helping to prepare the next generation of scientists in analytical techniques and instrumentation.