A new concept for high throughput defect detection with multiple parallel electron beams is described. As many as 30 000 beams can be placed on a footprint of a in.(2), each beam having its own microcolumn and detection system without cross-talk. Based on the International Technology Roadmap for Semiconductors requirements, some high level properties of the implementation of this concept were derived. A projection lens was designed that can both focus the primary beam into a small spot and simultaneously collect 75% of the secondary electrons. Conceptual design studies were performed for three crucial components of the detector chain: the scintillator, the light optics, and the detection array. The throughput of this concept is expected to be at least a factor of 300 higher than standard electron beam based defect detection systems. (C) 2007 American Vacuum Society.