Abstract

Much of the benefit from using higher voltage in the study of radiation sensitive biological samples is currently lost due to the deterioration in performance of existing electron imaging detectors at higher voltages. As the loss in performance cannot be made up for with increased dose there is strong interest in having better detectors, particularly for use at 300 kV. Of the detectors we have investigated, CMOS based monolithic active pixel sensors (MAPS) look the most promising. MAPS detectors are damaged by exposure to the electron beam but can be designed to have sufficient lifetime that their performance, especially when backthinned, promises a revolution in the investigation of radiation sensitive samples. The sensitivity and speed of MAPS detectors allow new ways to acquire data. In particular, it possible to achieve the ultimate in detector performance through the generation of a final image from the recorded signals of individual incident electrons.