USA - FSLUI

DEPARTMENT OF NUCLEAR, PLASMA, AND RADIOLOGICAL ENGINEERING
PLASMA-MATERIAL INTERACTION GROUP
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN

214 Nuclear Engineering Laboratory, 103 South Goodwin Avenue
Urbana, Illinois 61801-2984

Telephone: +1 217 333 0332
Telefax: +1 217 333 2906
URL:   http://starfire.ne.uiuc.edu

Staff
Ruzic, David N. (Dr., PI)
Allain, Jean Paul (B.S., M.S., PhD candidate, jpallain@starfire.ne.uiuc.edu , IIAX, FLIRE, IPVD)
Alman, Darren (B.S., M.S., PhD candidate, alman@students.uiuc.edu , Molecular Dynamics Simulation)
Li, Ning (B.S., M.S., PhD candidate, ningli@students.uiuc.edu , IPVD)
Neumann, Martin (B.S., mneumann@starfire.ne.uiuc.edu , Plasma Quest, FLIRE)
Nieto, Martin (B.S., M.S., PhD candidate, nieto@starfire.uiuc.edu , FLIRE)
Norman, Jeff (B.S., jnorman@students.uiuc.edu , Plasma Quest, FLIRE)

Experimental Facilities:
IIAX Facility
The Ion-surface InterAction Experiment (IIAX) facility is used to conduct research in both fusion and semiconductor areas. Absolute sputtering yields and angularly-resolved sputtering yields have been measured in IIAX. These include measurements of D+, He+ and Li+ bombardment of solid phase lithium and tin-lithium, as well as liquid phase lithium and tin-lithium. Other measurements include deuterium bombardment of Be, Ar+ and N+ bombardment of Ti and TiN, Ar+ bombardment of Al and Al-0.5%Cu. A Colutron ion source is used to create and accelerate gaseous or metal ions onto a 100 mm² metal target. The bombarding ions are mass-selected through an E X B filter and decelerated near the target. The target can be rotated in order to provide variation in the angle of incidence. A plasma cup is used to remove the first few monolayers and thus provide a ''clean'' surface. Two diagnostics are rotated in front of the target to collect the sputtered flux. A newly designed dual quartz crystal oscillator unit is used to measure the absolute sputtering yield. A new configuration has also been implemented to undergo absolute sputtering yield measurements from liquid metals. A small high-temperature, HV substrate heater has been added along with a temperature controller to effectively increase the temperature of metal samples such as lithium and tin-lithium. Current research in IIAX investigates the anomalous increase in physical sputtering yield from liquid metal targets bombarded by low-energy, light-ion particles.

FLIRE Facility
The goal of the Flowing Liquid-Surface Illinois Retention Experiment (FLIRE) is very straightforward. FLIRE will provide fundamental data on the retention and pumping of He, H, and other gases in flowing liquid surfaces. This will allow elucidation of the dominant phenomena that liquid surfaces will have on the plasma edge performance. The device initially utilizes an ion source for bombardment, which will be upgraded to a highly-intense plasma environment able to test significant heat load removal of > 1 MW/m² onto free surface flowing liquids. The upgrade will use an existing 250 kJ capacitor bank complete with power supplies and control circuitry. This type of plasma source would convert the FLIRE facility into a full-fledged plasma-flowing surface interaction test facility.

IPVD Facility
Semiconductor research is conducted in an ionized physical vapor deposition system in the PMI group at UIUC. The facility consists of a conventional magnetron deposition system donated by the Materials Research Corporation (now Tokyo Electron, Inc.), which uses a rf inductively coupled plasma for sputter deposition of a variety of materials. Research using the IPVD facility include characterization of magnetron-sputtered partially ionized deposition as a function of metal and gas species, the use of a helicon plasma source for IPVD, the use of a pulsed-system to grow aluminium-oxide films, and the study of TiN films in an IPVD system. The IPVD facility is currently doing research in thermally-activated IPVD deposition of aluminium-oxide films.

Plasma Quest Facility
A Plasma Quest 256 research reactor powered by a PMT Mori 200 Helical plasma source is used to study plasma-wave interactions. The reactor is a donation by the Intel Corporation. Magnetically enhanced inductively coupled plasmas can operate in very different modes and operating regimes simply through external control. Research is currently being done to device multi-functioning processing environments potentially replacing existing single-step process devices for semiconductor fabrication. Additional research uses the high-density plasma source to develop processes to treat polymers for biomaterial engineering applications, including protein-fouling, drug engineering, drug delivery systems, reduction of friction and wear-resistance of polymers.

Molecular Dynamics Simulation of Hydrocarbons Incident on a Graphite Surface
To aid in erosion/redeposition modeling of carbon plasma facing components, reflection coefficients for carbon atoms and hydrocarbon molecules incident on a 0.4 H:C graphite surface are calculated. Due to the low incident energies of interest, a molecular dynamics code is used. The code is written for dealing with covalently bonded materials and uses the Brenner hydrocarbon potential, which is an empirical many-body potential developed for hydrocarbons that can model intramolecular chemical bonding in a variety of small hydrocarbons as well as graphite and diamond lattices. The Brenner potential is based on Tersoff's covalent bonding formalism, with some additional correction terms added. It uses a fixed time step integrator, has no pressure bath to maintain a constant pressure, and applies periodic boundary conditions to the two directions parallel to the surface. At the boundaries, the Berendsen velocity scaling method is used to couple the target to an external bath, keeping the target temperature constant. In addition to text output of the results, graphical output is supported through the output of a sequence of scene files that can be rendered using freeware ray-tracing programs such as Rayshade or POV-Ray for Windows. In order to obtain adequate statistics for the reflection coefficients many flights are run, each with a random impact location on the surface.

Funding
1) DOE ALPS Program (Advanced Limiter/Divertor Plasma-facing Surfaces)
2) DOE Argonne National Laboratory

Staffing Level
1 Principal Investigator/Faculty
6 Graduate Students
6 Undergraduate Students