EBSD datasets for: Direct large-area observation of subsurface plastic activity in conditioned copper electrodes

Electron backscatter diffraction (EBSD) misorientation datasets for nine regions of interest on two OFE copper cathodes from the CERN pulsed-DC Large Electrode System: a cathode conditioned at surface fields up to ~80 MV/m in a sloped-anode geometry, and an unexposed reference cathode with identical machining and heat treatment. The deposit contains per-ROI nearest-neighbor misorientation-angle histograms (0–5° window at 0.1° bins; full range at 1.4° bins) exported from OIM Analysis, and a JSON file of derived per-ROI statistics (distribution moments and maximum-likelihood gamma parameters with bootstrap confidence intervals). Acquisition: 15 kV, 3.2 nA, 3 µm hexagonal grid, 500-µm-wide ROIs, no data-cleaning filters. Add per-ROI grain-size distributions. See README.txt inside the archive for file formats and ROI positions. These data underlie the figures and table of the associated article.