A differential sputter yield measurement technique is described, which consists of a quartz crystal monitor that is swept at constant radial distance from a small target region where a high current density xenon ion beam is aimed. This apparatus has been used to characterize the sputtering behavior of various forms of carbon including polycrystalline graphite, pyrolytic graphite, and PVD-infiltrated and pyrolized carbon-carbon composites. Sputter yield data are presented for pyrolytic graphite and carbon-carbon composite over a range of xenon ion energies from 200 eV to 1 keV and angles of incidence from 0 deg (normal incidence) to 60 deg .

This thesis in an assessment of attack helicopter gunnery training and the adequacy of that training as the Army fields the AH-64D Longbow attack helicopter starting in 1997. The problem confronted by this study is both institutional and unit gunnery training. This thesis is supported by an overview of the current helicopter gunnery training strategy and contains a history of the development of the attack helicopter, as well as the expectations of Aviation Branch in Force XXI. Finally, a comparison of capabilities is conducted between the AH-64A and the AH-64D. The thesis draws several conclusions. First, the current helicopter gunnery training strategy is not acceptable for the Longbow. Second, the gunnery infrastructure is insufficient to assist commanders, analyze trends, and incorporate lessons learned. Third, the training aids and simulators available to the Longbow unit commander will likely be inadequate. The majority of the analysis in this thesis focuses on the human dimension of attack helicopter employment. Army aviators will continue to employ helicopters in combat through the foreseeable future; therefore, training should focus on preparing them for that combat and the uncertainty that will confront them. By focusing on technology, the importance of human strengths and weaknesses may be overlooked.