Recent Developments in Dual-Laser Digital Holography for Plasma-Facing Surface Characterization

Journal Article · Mon Oct 14 00:00:00 EDT 2019 · IEEE Transactions on Plasma Science

DOI:https://doi.org/10.1109/TPS.2019.2943739· OSTI ID:1607086

Smith, Cary D. ^[1]; Biewer, Theodore M. ^[2]; Ren, Xi ^[3]; Thomas, C. E. ^[4]; Gebhart, III, Trey ^[2]; Zhang, Zhili ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Beloit College, Beloit, WI (United States)
4. Third Dimension Technologies, Knoxville, TN (United States)

A digital holography device is currently undergoing development at the Oak Ridge National Laboratory for the purpose of measuring surface topography, with the goal of deployment as a real-time plasma-facing component diagnostic for the study of materials that could be utilized in a nuclear fusion device. The holography system utilizes one or two lasers depending on the scale of surface features under measurement. Measurements of surface roughness were performed in a single-laser mode and compared with the data from profilometry, with a linear correlation of increased holographic measurement fidelity as surfaces became smoother. Characterization of the dual-laser operating mode has been performed via surface measurement of stainless steel targets with ``stair-step'' features in various sizes. Results demonstrated that surface features with known sizes as small as 25.4 μm could be resolved. Measurements were within ~55 μm or less deviation from the actual sizes, and measurement accuracy was improved as feature size was increased, corresponding to the effect of noise becoming less pronounced. In conclusion, a target exposed to plasma generated by an electrothermal (ET) arc source was analyzed with flat-field correction and averaging of sequential image frames to demonstrate the improved measurement quality in preparation for future use of holography on ET arc-exposed targets.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1607086
• Journal Information: IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 6 Vol. 48; ISSN 0093-3813
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
digital holography (DH)
nuclear fusion
plasma diagnostic
plasma-facing component (PFC)
plasma-material interaction (PMI)