Application of slow-scan CCD cameras in routine biological TEM

Abstract

Slow scan CCD (charge-coupled device) cameras (SSCs) are based on image detection technology introduced in the seventies and first used in astronomy in the eighties. When they are properly configured for the detection of medium energy electrons rather than photons, they are able to capture images whose quality exceeds the quality of images recorded on photographic film. Here we discuss aspects of their operation pertinent to routine biological TEM.Compared to the TV-rate CCD sensors that have become ubiquitous in miniature camcorders, scientific (astronomy-grade) CCDs have several unique characteristics: 1) their pixels are typically 20-27 μm in size rather than the 6 μm typical of TV rate CCDs, 2) their read-out amplifiers are optimized for low noise at read out rates of 1/10 to 1/100 of TV rate, 3) they do not have a separate frame-transfer buffer for CCD read-out, and 4) they are available in large total sizes (up to 2048 × 2048 pixels).