Scanning Electron Microscope and Ion Beam Milling System for Nanoscale Analysis of Next-Generation Thermionic Cathodes and Novel Nanostructured Materials
Abstract
The University of Kentucky (UK) requests support from the Department of Defense (DoD) to acquire a scanning electron microscope (SE M) with specialized analytical components forcharacterizing a range of materials using state-of-the-art techniques that will enable next generation technology in support of DoD missions. The proposed SEM will also serve the research community interested in mate rials characterization, and this additional utilization willenable cost recovery to support and sustain the new SEM. The existing e lectron microscopes in the Electron Microscopy Center (EMC) at UK offer excellent capabilities for general materials characterizat ion, but do not allow the analysis of elemental/compositional aspects of specimenswith the nanoscale resolution that is needed to c haracterize many modern materials.We propose to acquire a new SEM to establish state-of-the art nanoscale imaging andanalytical ca pabilities at UK, serving key needs for multiple current DoD-funded projects as well as pending projects. Two current projects on d ispenser cathodes, which lie within the realm of Directed Energy Weapons and Electronic Warfare technology, will immediately benefi t from the proposed instrument: Reliable Manufacturing of Scandia-Doped Tungsten Powders for Thermionic Cathodes (Phase 2), fun ded by the Navy STTR program; and Escaping the Refractory Limit: Enabling New VED Operational Paradigms Through Mechanism-Based Re Engineering of Thermionic Cathode Emitting Materials, funded by the Defense Advanced Research Projects Agency (DARPA). Additional ly, the SEM would impact multiple projects currently underway at UK, led by co-PIs Dr. Chad Risko (Department of Chemistry) and Mr. John Craddock (Center for Applied Energy Research). Moreover, Dr. Howard Roberts (Division of Restorative Dentistry) is developin g projects of interest to AFOSR, which would also benefit from this equipment.The proposed instrumentation includes a high-resolut ion SEM, with analytical capabilities geared toward surface measurements and also capable of extremely high spatial resolution. Re cent developments in the analysis of low-energy x-rays (typically below 1 keV) emitted from the near-surface region of a sample fac ilitate characterization with low beam voltages in the SEM; in turn, the low beam voltage creates a shallow penetration depth (also down to ~10 nm), which enables a scanning nanoprobe mode for surface analytical measurements, i.e. combined imaging and elemental analysis with nanoscale spatial resolution. Additionally, an electron backscatter detector (EBSD) is included in the proposed conf iguration, for the nanoscale measurement of crystal structure/orientation. This combination of imaging and analytical capabilities will establish a unique system for the thorough characterization of nanoscale phases in near-surface sample regions. The second pa rt of this instrumentation proposal is an ion beammilling system, for the preparation of large-area, ion-polished surfaces and cros s-sections without introducing artifacts that would obscure nanoscale structure and phase distribution.The proposed instrumentatio n would enable transformative research and significantly advance understanding of dispenser cathodes as well as other DoD-relevant materials. There remain a number of unanswered questions regarding nanoscale material phase and compositionin these materials, an d answering these key questions will be greatly facilitated by the state-ofthe-art capabilities that are proposed here
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 07, 2021
- Source ID
- N000142112894
Entities
People
- Thomas Balk
Organizations
- Office of Naval Research
- United States Navy
- University of Kentucky