Prospects for hybrid pixel detectors in electron microscopy

The current status of CCD-based detectors for cryo-electron microscopy of membrane and other proteins is described briefly, highlighting the strengths and weaknesses of the technique. Over the past few years CCD detectors have been used extensively in electron crystallography of membrane proteins, and in particular, in the study of the molecular transitions which take place during the photo-cycle of the light-driven proton pump bacteriorhodopsin. Direct-detection methods, which avoid the intermediate stages of converting the electron energy into light, offer the possibility of improved spatial resolution compared to CCD detectors; in addition, photon counting and noise-free readout should improve the signal-to-noise ratio.