title: A high-speed area detector for novel imaging techniques in a scanning transmission electron microscope.
abstract: A scanning transmission electron microscope (STEM) produces a convergent beam electron diffraction pattern at each position of a raster scan with a focused electron beam, but recording this information poses major challenges for gathering and storing such large data sets in a timely manner and with sufficient dynamic range. To investigate the crystalline structure of materials, a 16x16 analog pixel array detector (PAD) is used to replace the traditional detectors and retain the diffraction information at every STEM raster position. The PAD, unlike a charge-coupled device (CCD) or photomultiplier tube (PMT), directly images 120-200keV electrons with relatively little radiation damage, exhibits no afterglow and limits crosstalk between adjacent pixels. Traditional STEM imaging modes can still be performed by the PAD with a 1.1kHz frame rate, which allows post-acquisition control over imaging conditions and enables novel imaging techniques based on the retained crystalline information. Techniques for rapid, semi-automatic crystal grain segmentation with sub-nanometer resolution are described using cross-correlation, sub-region integration, and other post-processing methods.
authors.affiliation: Physics, Cornell University, 162 Clark Hall, Ithaca, NY 14853, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Caswell
authors.forename: P
authors.initials: P
authors.lastname: Ercius
authors.forename: M W
authors.initials: MW
authors.lastname: Tate
authors.forename: A
authors.initials: A
authors.lastname: Ercan
authors.forename: S M
authors.initials: SM
authors.lastname: Gruner
authors.forename: D A
authors.initials: DA
authors.lastname: Muller