A tiled CCD detector with 2×2 array and tapered fibre optics for electron microscopy

Charge coupled devices (CCD)-based detectors have made a major impact on data collection in electron microscopy over the past few years. There have been a number of successful applications of CCDs in electron crystallography of two-dimensional protein crystal arrays but high-resolution imaging has been hampered by the relatively poor spatial resolution (and fewer independent pixels) compared to film. A partial solution to this problem, presented in this paper, are to design detectors with larger effective pixel sizes and with more pixels. A CCD detector with a much greater number of ‘independent’ pixels, achieved by tiling a 2×2 array of CCDs, each of which has 1242×1152 pixels is described here. The sensitive area of the detector, using fibre optics with a demagnification of 2.5 : 1, is 140×130 mm2; the pixel size is 56 μm square and there is a total of ∼2500×2300 pixels.