In situ spectroscopic erosion yield measurement with applications to sputtering and surface morphology alterations
An in situ spectroscopic erosion yield measurement is developed and used to monitor material surface erosion during bombardment by a plasma. The experiments are performed in a plasma that has the characteristics of a fusion tokamak boundary plasma but the technique is applicable to many processes where plasma erosion is important. Erosion yield of materials bombarded in a high flux (up to 10/sup 18/ ion/cm/sup 2/ s) plasma environment has been previously studied using weight loss measurements. In the present study, the sputtered flux from a material is monitored by the line emission intensities of atoms eroded from the surface. The line intensities can be used to infer erosion yields after proper calibration. The method agrees well with results from weight loss measurements. Earlier work established that the material surface structure can substantially influence the erosion yield. When a change of surface morphology (e.g., cone formation) occurs, weight loss methods cannot be used to determine the erosion yield. However, the in situ erosion measurement is suitable and is used to investigate the relation between the onset of morphology changes and alternations in erosion yield during plasma bombardment. Experiments are reported for copper, as an example of a pure material, and stainless steel, as an example of an alloy system. The formation of surface cones is observed only when both the sample temperature is above a critical value and surface impurities exist. If the source of impurities is removed, or the sample temperature is lowered below the critical value, a surface rough with cones will be returned to a smooth state.
- Research Organization:
- Mechanical, Aerospace and Nuclear Engineering Department and Institute of Plasma and Fusion Research, University of California, Los Angeles, California 90024
- OSTI ID:
- 6582298
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 7:1
- Country of Publication:
- United States
- Language:
- English
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In situ spectroscopic measurements of erosion behavior of Tokamak Fusion Test Reactor-redeposited carbon materials under high-flux plasma bombardment in PISCES-A (Plasma Interactive Surface Component Experimental Station-A)
In situ spectroscopic measurements of erosion behavior of Tokamak Fusion Test Reactor redeposited carbon materials under high-flux plasma bombardment in Plasma Interactive Surface Component Experimental Station-A
Related Subjects
COPPER
ION COLLISIONS
MORPHOLOGY
SPUTTERING
STAINLESS STEELS
THERMONUCLEAR REACTOR WALLS
DIVERTORS
EROSION
FIRST WALL
IMPURITIES
LIMITERS
MATERIALS
PLASMA
TOKAMAK DEVICES
ALLOYS
CLOSED PLASMA DEVICES
COLLISIONS
ELEMENTS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
METALS
STEELS
THERMONUCLEAR DEVICES
TRANSITION ELEMENTS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing