$tem diffraction pattern analysis$

$tem diffraction pattern analysis$

A commercial solution offers both hardware ( that contains beam scanning and precession for TEMs and optical camera to photo the viewing screen) for recording the data set and software for creating phase maps and orientation maps from it. There are several different solutions in the literature both for the recording and for the evaluation of such 4D-ED data sets.

$tem diffraction pattern analysis$

taking picture of the viewing screen, recording with conventional CCD or CMOS cameras or with pixelated detectors). selected area (SAED), nanobeam (NBD), convergent beam (CBED)) and also on the means of recording (e.g. There is a wealth of information in such 4D data sets, depending both on the type of electron diffraction recorded (e.g. Others call it scanned electron diffraction (SED). This mode of data collection produces a four-dimensional (4D) data set, since at each pixel of a 2D image a 2D-ED is saved. There is also an additional possibility to record a 2D-ED at each position of the beam (each position corresponding to a pixel of the HAADF image). a high angle annular dark-field (HAADF) detector). The beam is scanned line-by-line along a rectangle and an image is formed by a pre-selected electron detector (e.g. Scanning transmission electron microscopes (STEMs) brought the possibility to record such 2D-ED patterns systematically from many locations in a single experiment.

$tem diffraction pattern analysis$

This 2D-ED pattern carries structural information about the given location of the sample. Similarly, an electron diffraction (ED) pattern recorded at any locations of the sample is also 2D. Traditional electron microscopic imaging evaluates two-dimensional (2D) images recorded with different contrast mechanisms. Application is exemplified on the (fcc, hcp and bcc) phases in a sample with 4 major components (Co, Cr, Fe, Ni). These phase and orientation maps can complement usual compositional maps collected in the same STEM with energy dispersive x-ray spectrometers (EDS) to give a complete description of the crystalline phases. Many STEMs can collect such a four-dimensional electron diffraction (4D-ED) data sets by proper selection of microscope parameters, even if this fact is not over-emphasized in the operating manuals. The patterns, which are recorded independently from this program by a CCD or CMOS camera or by a pixelated camera are in Tif format, serve as input to DiffMap. The program runs in the Windows operating system on IBM PC compatible computers. A free computer program, called DiffMap, is presented for off-line evaluation of both phase maps and orientation maps from a large number of diffraction patterns recorded with a nearly parallel nano-beam scanned line-by-line over a rectangular area in a scanning transmission electron microscope (STEM).

$tem diffraction pattern analysis$

Tem diffraction pattern analysis