Non-destructive, comprehensive dislocations characterization in fine grained Interstitial-Free Steel was realized for the first time by Accurate Electron Channeling Contrast Imaging "A-ECCI" in a Scanning Electron Microscope. Conventional Transmission Electron Microscopy gÁb = 0 invisibility criterion and trace analysis were applied to determine Burgers vectors and line directions in this bulk material. This approach relies on the live collection of High Resolution Selected Area Channeling Patterns "HR-SAC-Ps" using an innovative procedure to rock the beam with a remarkable spatial resolution of about 1 lm.

Collection of selected area channeling patterns (SACPs) on a high resolution FEG-SEM is essential to carry out quantitative electron channeling contrast imaging (ECCI) studies, as it facilitates accurate determination of the crystal plane normal with respect to the incident beam direction and thus allows control the electron channeling conditions. Unfortunately commercial SACP modes developed in the past were limited in spatial resolution and are often no longer offered. In this contribution we present a novel approach for collecting high resolution SACPs (HR-SACPs) developed on a Gemini column. This HR-SACP technique combines the first demonstrated sub-micron spatial resolution with high angular accuracy of about 0.1°, at a convenient working distance of 10mm. This innovative approach integrates the use of aperture alignment coils to rock the beam with a digitally calibrated beam shift procedure to ensure the rocking beam is maintained on a point of interest. Moreover a new methodology to accurately measure SACP spatial resolution is proposed. While column considerations limit the rocking angle to 4°, this range is adequate to index the HR-SACP in conjunction with the pattern simulated from the approximate orientation deduced by EBSD. This new technique facilitates Accurate ECCI (A-ECCI) studies from very fine grained and/or highly strained materials. It offers also new insights for developing HR-SACP modes on new generation high-resolution electron columns.