Experimental and Modeling Studies of Low Energy Ion Sputtering in Ion Thrusters

Abstract

I enjoyed working with all of them. I was impressed with their skills and professionalism. I would like to thank them for all the assistance they provided me over the course of my research. Although they had doubts that I would ever collect enough data, they never stopped supporting me. The technicians at GRC were always willing to listen my crazy ideas and figure out how to make them a reality. I would like to thank these technicians for their high quality workmanship. Thanks especially to Pat Barber, Jim Coy, Wayne Gerber, Chris Kandrach, Mike Pastel, Rich Polak, Dennis Rogers, and Bob Roman. They will receive a copy of my diploma as proof that I actually finished my degree. Materials folks at GRC, Dave Hull, Joy Buehler, and Tiffany Biles provided assistance in analyzing my molybdenum samples. I want to thank them for helping me with sample preparation and showing me how to use the microscope equipment. I would like to thank ESML at PNNL for the use the RBS facility. I would like to personally thank V. Shutthandan and Yanwen Zhang for their willingness to schedule time for me in the laboratory. They did a professional job in the RBS analysis. Thanks, too, to the other students I worked with at GRC. Alex Kieckhafer, Sonca Nguyen, and Tyler Hickman made time in the lab go quickly. Ken Street at GRC helped me use the microbalance. I appreciated his time and willingness to support my research. I would like to thank Sharon Miller for serving as my grant monitor. Her effort to take care of the administrative aspects of the grant was appreciated. I want to thank Chris Hall for serving on my advisory committee. I enjoyed having him as a professor at Virginia Tech. I greatly appreciated the support of my family and close friends throughout my graduate school career. They never wavered in cheering me on to the finish line.

Sputtering of cubic metal crystals by low-energy xenon-ions

“…We acknowledge that inaccuracies will arise from this process since it was done by hand. Lastly, Nakles [6] provides experimentally measured sputter yields for molybdenum under low-energy xenon-ion bombardment collated from a number of sources (see 10,[16][17][18][19][20][21][22].…”

“…This first issue has particular relevance for modeling ion thruster erosion since most sputtering events in this system occur at low ion energies. The second issue has relevance more broadly, as experimental sputtering data shows a wide spread in the measured yield [6]. Recently increasing computational power and high-level interatomic potentials have allowed atomistic simulations of sputtering to rapidly progress.…”

“…Sputter yields are computed from these simulations and compared with experimental results taken from the literature [10,4,6]. As molybdenum grids are the current industry standard material, we then go on to compute a number of sputtering statistics in greater detail for the xenon-molybdenum system.…”

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

“…6,9,[33][34][35][36] In addition, this approach is capable of accurate quantifying sputtering rates for organic materials and solids under bombardment with a variety of primary species, commonly used atomic ions and relatively new molecular and cluster ions, such as in Refs. 37, 38.…”

Characterization of Near Field Plasma Environment of a Hollow Cathode Assembly

“…Theoretical and experimental investigations have attempted to quantify low-energy ion sputtering (<100 eV), 3,4 which is believed to be the cause of erosion in ion thrusters. The ion energy levels required for erosion and the origin of the ions is not well defined.…”