Diffraction analysis package
The Gatan DIFPACK Module automates analysis of diffraction patterns and diffractograms. Measure spacing and angles between spots easily. Automatically keep track of all measurements and export them to word processors and plotting software. With DIFPACK you can measure:
- Diffraction spot (reciprocal) distance
- Angle to reference spot
- Angle to x-axis
- Brightest pixel amplitude for any spot in a diffraction pattern or diffractogram
- Automatic measurement management: Results are displayed as text and can be easily copied for use in other applications. All results are stored with the image, keeping them organised and making it easy to retrieve previous data. Individual measurements can be hidden, shown, deleted or listed.
- Improved diffractogram: The calculation of the diffractogram of a lattice image is preceded by masking in real-space. This eliminates streaking and improves accuracy. Lattice image regions and diffractograms are tracked automatically, for direct visual feedback of the region being analysed.
- Accurate peak location: Search peaks automatically and refine with sub-pixel accuracy using:
- Centre of mass calculation (for diffraction patterns)
- Interpolation (for diffractograms)
- Optimised calibration: Using peak location, calibrate magnification directly and accurately in reciprocal space. Diffractograms can be calibrated directly in reciprocal space or from the lattice image. Calibrations are automatically transferred between real and reciprocal space. The scale and units of the reference image can also be transferred to other images.
- Center location: Automatically locate the centre of diffraction patterns using a cross-correlation technique (for centrosymmetrical patterns). It can also be determined manually from a pair of spots located symmetrically around a central spot. Centers can be averaged to improve accuracy. Centres can also be identified manually and directly, when there are no symmetrical spots.
- Background thresholding: Background noise can be automatically distinguished from dim spots using an empirically determined threshold parameter.
- Flexible data types: Operates on integer 1, 2 and 4 bytes, real 4 and 8 bytes, complex 8 and 16 bytes, packed complex (after automatic conversion to complex 8) and RGB (after manual extraction of amplitude channel).