Simulation and characterization of a miniaturized Scanning Electron Microscope

A miniaturized Scanning Electron Microscope (mini-SEM) for in-situ lunar investigations is being developed at NASA Marshall Space Flight Center with colleagues from the University of Alabama in Huntsville (UAH), Advanced Research Systems (ARS), and the University of Tennessee in Knoxville (UTK). Scanning Electron Microscopes (SEMs) can provide information on the size, shape, morphology and chemical composition of lunar regolith. Understanding these basic properties will allow us to better estimate the challenges associated with In-Situ Resource Utilization and to improve our basic science knowledge of the lunar surface (either precluding the need for sample return or allowing differentiation of unique samples to be returned to Earth.) Miniaturization (and power reduction) of an SEM appropriate for in-situ planetary investigations has warranted several novel re-designs of traditional SEM components. As such, this research has been centered on these principle elements and includes: an electron gun, beam defining and focusing system, and deflection/scanning/imaging system. Of these, the electron gun development, which is the focus of this paper, is of particular importance as it dictates the design and operation of the remaining components.