Bulletin of the American Physical Society
59th Annual Meeting of the APS Division of Plasma Physics
Volume 62, Number 12
Monday–Friday, October 23–27, 2017; Milwaukee, Wisconsin
Session JO4: Spherical Tokamaks, Other
2:00 PM–5:00 PM,
Tuesday, October 24, 2017
Chair: Kathreen Thome, General Atomics
Abstract ID: BAPS.2017.DPP.JO4.11
Abstract: JO4.00011 : Elemental and topographical imaging of microscopic variations in deposition on NSTX-U and DIII-D samples*
4:00 PM–4:12 PM
Preview Abstract Abstract
Tokamak plasma facing components (PFCs) have surface roughness that can cause microscopic spatial variations in erosion and deposition and hence influence material migration. Previous RBS measurements showed indirect evidence for this but the spatial (~0.5mm) resolution was insufficient for direct imaging. We will present elemental images at sub-micron resolution of deposition on NSTX-U and DiMES samples that show strong microscopic variations and correlate this with 3D topographical maps of surface irregularities. The elemental imaging is performed with a Scanning Auger Microprobe (SAM) that measures element-specific Auger electrons excited by an SEM electron beam. 3D topographical maps of the samples are performed with a Leica DCM 3D confocal light microscope and compared to the elemental deposition pattern. The initial results appear consistent with erosion at the downstream edges of the surface pores exposed to the incident ion flux, whereas the deeper regions are shadowed and serve as deposition traps.
*Support was provided through DOE Contract Numbers DE-AC02-09CH11466, DE-FC02-04ER54698 and DE-NA0003525.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.DPP.JO4.11
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