Invited Talk: Sol M. GrunerAbstract Title: EMPAD, an integrating scanning transmission electron microscope pixel array detector*

Modern scanning transmission electron microscopes are powerful tools to probe the physical properties of thin sheet materials. However, extracting maximum information from the electrons transmitted through the sample imposes numerous constraints on the detector. The Cornell electron microscope pixel array detector (EMPAD) developed by a collaboration of the Cornell Detector Group and David Muller’s electron microscope group meets many of these constraints, including: (1) A detector sensor of sufficient thickness to convert all of the incident electron energy to a measured current of electron or hole carriers without unduly compromising image spatial resolution.  (2) An array of pixel size and shape well matched to the width of the carrier cloud produced in the sensor. (3) A dynamic range that spans from low-noise detection of single incident electrons to high currents (e.g., few hundred pA) per pixel per exposure, at electron energies ranging from ~60 to 300 keV. (4) Very rapid image acquisition to limit deleterious effects of sample movement over time. (5) A detector configuration that is robust, stable, and resistant to radiation damage. (6) A detector configuration that accommodates relatively easily into common STEM platforms. This talk will discuss the technical development of the EMPAD from conception to the devices now implemented in many STEM laboratories.