MRI: Acquisition of a Time-of-Fight Secondary Ion Mass Spectrometer

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Non-Technical Description:This Major Research Instrumentation award provides support for the acquisition of a state-of-the-art instrument for time-of-flight secondary ion mass spectrometry (ToF-SIMS). This is a critical technique needed to understand surface composition and reactivity across chemistry, materials science, environmental science, chemical engineering, conservation science, and physics. The ToF-SIMS method is an extremely sensitive surface analytical technique that uses a pulsed ion beam to remove the outmost monolayers of the sample. The species that are removed from these atomic monolayers (secondary ions) are accelerated and their masses (or more precisely mass-to-charge ratios) are determined by the exact time at which they reach the detector (hence time-of-flight). In a broader sense, the acquisition of this instrument supports collaboration efforts among the different colleges at the University of Delaware, industrial companies in the state of Delaware, and the Winterthur Museum. The instrument is used by students in graduate and advanced undergraduate research, graduate courses, the Art Conservation Program, and students in several research experience for undergraduate programs at the University of Delaware, including research experience specifically designed for students with disabilities.Technical Description:In general, there are three ToF-SIMS operational modes: surface spectroscopy with better than 0.0001 amu resolution that enables molecular identification and isotopic content in the parts-per-million range; surface imaging with better than 100 nm spatial resolution, ~3000x smaller than the diameter of a human hair; and depth profiling - when combined with a second ablation beam (generally, ions of oxygen and cesium) to achieve vertical resolution of less than 1 nanometer. The acquired instrument satisfies all these criteria. These capabilities directly affect a large number of current and future research directions at the University of Delaware. The research areas include atomic-precision deposition and etching, nanotechnology and nanomaterials, efficient solar-cell design, heterogeneous, thermal, and electrocatalysis, cultural heritage investigations, research in microplastics and biomedical interfaces, and many other efforts. ToF-SIMS provides a powerful method with atomic precision, surface-sensitivity, high depth resolution, and imaging capabilities to answer critical questions and to define further research and discovery directions.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.