NSF Facility

The University of Wisconsin SIMS lab (WiscSIMS) was installed in 2005 and became a National Facility for Stable Isotope Geochemistry in 2008 with support from NSF, Division of Earth Sciences, Instrumentation and Facilities Program (link).

As of 2014, the lab has experience with analysis of Li, C, O, Mg, Si, and S isotope ratios. Best results come from well-prepared samples that are vacuum stable, have a smooth, flat, low-relief surface, are 25 mm in diameter and <6 mm thick (see our sample preparation page). Surface relief is minimized by careful polishing and is measured at sub-μm-scale by white light profilometer. Other materials can be analyzed, as can isotope ratios for trace elements. Accurate analysis requires well characterized, homogeneous standards with similar chemistry and crystal structure to samples. For oxygen isotope ratios, WiscSIMS has many silicate, carbonate, and oxide standards (Valley & Kita 2009; Page et al., 2010). Other standards exist or are being developed. Potential users should inquire about standard availability.

Use of associated instrumentation at nominal cost can be arranged in support of projects at WiscSIMS including: an Hitachi S3400N Variable Pressure Scanning Electron Microscope with  capability for imaging uncoated samples, Electron Back Scatter Diffraction (EBSD), color-filtered CL, EDS, and BSE detectors; a CAMECA SXFiveFE electron microprobe with 5 crystal spectrometers, Field Emission Gun, EDS, CL, and BSE; conventional and laser fluorination stable isotope lab; and a white light optical profilometer.