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Scanning Transmission Electron Microscopy Facility

STEM Data Format

   STEM images consist of 512 x 512 pixels with two 8-bit channels (interleaved) of data and a 4096 byte header. For convenience, 64 such images are packaged into a folder with a name such as nk9285\nk928564.dat. The last two digits are the file number. One such folder contains 32.2 MB of data. A text editor with large capacity can open such a file to view the header.

For example:
NK9285 FILE64STEM bsmv vanadate U18696 04/30/0915:24:28 0.256 1.6263 6.5707 -146.0 -8.7 208.978d 5.

   The third field "STEM" is the user name for the grid being imaged. The next fields contain additional specimen description. The "U18696" is a unique grid identifier, followed by the date & time the image was recorded, the scan width in microns, the x and y electrical offsets of the beam in microns, the x and y stage offsets in microns, the dose in el/A2 and the preamp gain. The PCMass program displays the header information at the left margin below the large angle image.

   PhotoShop can open these images using the "open as" option in the File Menu and selecting the "Raw" option and entering 4096 for the header size and 512 for both height and width. However the header will not be displayed and mass measurement will not be supported.


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Last Modified: June 12, 2009
Please forward all questions about this site to: Kathy Folkers

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