readme.txt Title of paper Elemental and topographical imaging of microscopic variations in deposition on NSTX-U and DIII-D samples Author(s): C.H. Skinner, C.P. Chrobak, R. Kaita, B.E. Koel Name of Journal: Nuclear Materials and Energy Keywords: Erosion, Deposition, NSTX-U, DiMES, Plasma-Materials Interaction, Surface Analysis Abstract: Tokamak plasma facing components have surface roughness that can cause microscopic spatial variations in erosion and deposition and hence influence material migration, erosion lifetime, dust and tritium accumulation, and plasma contamination. However high spatial resolution measurements of deposition on the scale of the surface roughness have been lacking to date. We will present elemental images of graphite samples from NSTX-U and DIII-D DiMES experiments performed with a Scanning Auger Microprobe at sub-micron resolution that show strong microscopic variations in deposition and correlate this with 3D topographical maps of surface irregularities. The NSTX-U samples were boronized and exposed to deuterium plasmas and the DiMES samples had localized Al and W films and were exposed to dedicated helium plasmas. Topographical maps of the samples were performed with a 3D confocal optical microscope and compared to the elemental deposition pattern. The results revealed localized deposition concentrated in areas shadowed from the ion flux, incident in a direction calculated (for the DiMES case) by taking account of the magnetic pre-sheath. Attached data files are Fig1a.jpg jpg image Fig1b.jpg jpg image Fig2.csv csv files containing X,Y coordinates of points in plot Fig3a.jpg jpg image Fig3b.jpg jpg image Fig4a.jpg jpg image Fig4b.csv csv files containing X,Y coordinates of points in plot Fig5.jpg jpg image Fig6a.csv csv files containing X,Y coordinates of points in plot Fig6b.csv csv files containing X,Y coordinates of points in plot Fig7.csv csv files containing X,Y coordinates of points in plot Fig8.jpg jpg image Fig9a.jpg jpg image Fig9b.csv csv files containing X,Y coordinates of points in plot