MRI Track 1: Acquisition of a next-generation electron probe micro-analyzer (EPMA) for interdisciplinary cutting-edge science

University Of Nevada Las Vegas, Las Vegas NV

Investigators

Abstract

This major research instrumentation (MRI) project enabled the acquisition of a JEOL JXA-ISP100 Electron Probe Micro-Analyzer (EPMA) at the University of Nevada, Las Vegas. The EPMA is an instrument designed to image and analyze elemental compositions of materials at ultra-high magnification. The newest generation of EPMA will provide a springboard for diverse and cutting-edge research on a range of samples, as the instrument will be optimized to allow us to measure very small quantities of different elements in a range of materials, including Earth rocks and meteorites. This instrument will attract a diverse community of researchers to explore questions in many fields of science and engineering, including, geological sciences, chemistry, physics, material science, planetary sciences, and radiochemistry. For each of the research areas, undergraduate and graduate students as well as post-doctoral researchers will be actively trained and involved in research using the instrument. The new instrument will also be utilized in outreach projects that allow K-12 students to be directly exposed to STEM research, supporting current NSF-funded outreach programs. Instrument accessibility will also be increased through its remote-access capabilities. An EPMA is a versatile instrument for non-destructive chemical microanalysis (micron scale or 10-5 inches) of solid-state inorganic and organic materials. The new JEOL JXA-ISP100 EPMA allows for higher-quality imaging, mapping, and higher-precision analyses, including measurements of trace elements from boron to uranium, and light elements. The primary analytical advantages of the proposed EPMA over our current aging instrument are: 1) higher spatial resolution and analytical precision; the proposed EPMA can measure all naturally occurring elements in the periodic table except for hydrogen, helium, and lithium, with a detection limit as low as 10 ppm; 2) Lanthanum hexaboride (LaB6) cathode and tungsten (W) electron sources; LaB6 is brighter, permitting for a lower voltage (down to 5 kV) and an improved spatial resolution yielding a smaller beam size and a smaller volume from which the X-rays are emitted, important for small mineral features; 3) five Wavelength-Dispersive X-ray spectrometers (WDS) and large crystals; large crystals yield double the count rate of standard crystals without sacrificing the signal-to-noise ratio, allowing trace elements to be easily measured; 4) one EDS detector, allowing for faster analyses; and 5) Probe for EPMA software and remote access. This new instrument will be primarily used for applications related to igneous petrology, volcanology, mineralogy, and geochronology, economic geology, planetary science and extraterrestrial sample investigation, medical geology, radiochemistry, and materials research. This award was funded by the Division of Earth Sciences and from the Instrumentation and Facilities program. 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.