Direct Electron Imaging Using Back Thinned CCDs . EBCCD Principles . Back-illuminated CCDs are sensitive to kilovolt-energy electrons incident on the back surface through the EBS gain process. ... Backside enhancement techniques such as UV charging, ion implanting, and annealing and flash gate technologies are designed to reverse the field near the surface so that electrons generated there are repelled and collected in the CCD well. ... Cross-sectional drawing of a proximity focused EBCCD. ...