Single event imaging for electron microscopy using MAPS detectors

Monolithic active pixel sensors, MAPS, combine sensitivity to individual incident electrons with fast readout. This combination allows single event imaging, in which the final image is assembled from the information in the images of individual incident electrons to be implemented. This mode of imaging offers higher detective quantum efficiency and increased lifetime of the detector. Problems faced in processing the single electron events are discussed. It is proposed that the individual electron contributions should be accumulated into a final image with a probability distribution representing the uncertainty of their arrival position due to scattering. The use of a shadow image of a grid is advocated as a way to compare different methods for processing single electron events. Finally an example of a single event image is presented.