Kinematic and Thermodynamic Effects on Liquid Lithium Sputtering

Results suggest that preferential sputtering of deuterium atoms over lithium atoms in D-treated samples significantly decrease the absolute sputtering yield of lithium by at least 60% in the case of He+ bombardment. The secondary sputtered ion fraction for lithium bombardment has been measured for a variety of incident particle energies and sample temperatures. The fractions measured vary from 55--70%. Liquid lithium sputtering at or just above the melting point shows little difference between solid and liquid phase sputtering. As the temperature is raised a non-linear enhancement is noted in the lithium-sputtering yield from various bombardment conditions for both liquid lithium and liquid tin-lithium. The enhancement measured in IIAX is caused by a combination of temperature-dependent effects. In addition, the evaporation flux measured in IIAX indicates coverage by segregated oxygen from the sample bulk. Other results include lithium-sputtering results under high-flux conditions (i.e. tokamak exposures) are consistent with lithium sputtering results in IIAX for solid lithium and temperatures near or at the melting temperature. All experimental results are complemented with Monte Carlo simulations using VFTRIM-3D, where a fractal dimension equal to 2.00, consistent with a flat surface, is used for the liquid phase cases. In addition to simulations analytical and semi-empirical models have been developed to help explain lithium-sputtering reductions by deuterium treatment and lithium-sputtering enhancement by possible thermal or displacement spike effects, among other mechanisms.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Nuclear Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Allain, Jean Paul

Contributors dc:contributor

• Ruzic, David N.

• Engineering, Nuclear

Language dc:language

eng

Identifier

(MiAaPQ)AAI3030403

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85891