This award is for the construction of two UHV test chambers which will be used for the development of a new type of highly coherent electron or ion source. The proposed instruments will combine the functions of a field-ion microscope, a field-emission microscope, and a low voltage field-emission electron gun. The field-ion microscope images will be used to characterize and form single-atom electron or ion emitting regions. The field-emission mode will be used for brightness measurements, and the tips will be evaluated for operation in a field emission gun. The main interest is the development and application of these sources for use in field- emission electron beam instruments for microanalysis and materials characterization. Applications of the new sources to low voltage reflection and transmission electron holography, low voltage scanning electron microscopy, electron and proton interferometry and electron spectroscopy. Quantum-mechanical and classical calculations of the emission properties accompany this research program. The ultimate interest is in the application of new electron and ion sources to the new electron-microscopy and microanalysis techniques under development at CHREM, which has about 60 users from the ASU community. One test chamber will be used for forming and evaluating single- atom tips, measuring the tip properties, such as coherence and brightness, will have FIM/FEG/FEM capability, and will be bakable to 200 C. The second chamber will have nearly the same configuration, with the main application being implementation of the single-atom sources into a simple low-voltage electron microscope column.
