  Precision and accuracy of quantitative scanning transmission electron
microscopy (STEM) methods such as ptychography, and the mapping of electric,
magnetic and strain fields depend on the dose. Reasonable acquisition time
requires high beam current and the ability to quantitatively detect both large
and minute changes in signal. A new hybrid pixel array detector (PAD), the
second-generation Electron Microscope Pixel Array Detector (EMPAD-G2),
addresses this challenge by advancing the technology of a previous generation
PAD, the EMPAD. The EMPAD-G2 images continuously at a frame-rates up to 10 kHz
with a dynamic range that spans from low-noise detection of single electrons to
electron beam currents exceeding 180 pA per pixel, even at electron energies of
300 keV. The EMPAD-G2 enables rapid collection of high-quality STEM data that
simultaneously contain full diffraction information from unsaturated bright
field disks to usable Kikuchi bands and higher-order Laue zones. Test results
from 80 to 300 keV are presented, as are first experimental results
demonstrating ptychographic reconstructions, strain and polarization maps. We
introduce a new information metric, the Maximum Usable Imaging Speed (MUIS), to
identify when a detector becomes electron-starved, saturated or its pixel count
is mismatched with the beam current.
