For a 0D measurement the 2theta position of the detector arm is measured to a high precision together with the total intensity captured on the detector sensor. For each 2theta position a single intensity value is collected.
These days 0D applications are texture and stress measurements using an open detector, basic SAXS measurements without an evacuated beam path, high-resolution measurements using a triple- or double-bounce analyzer and reflectometry using a parallel plate collimator and reflectivity slits. Whilst dedicated 0D ‘point’ detectors are available and provide a cost-effective solution, the hybrid pixel detectors are increasingly popular as 0D detectors because of their low intrinsic noise and their capacity to measure the highest intensities without saturation.
In 1D mode, the 2theta position of the detector arm is recorded to a high precision. The detector is subdivided into equal strips, each strip corresponds to a 2theta position with its own unique relationship to the detector arm. During scanning mode the intensities of strips with the same absolute positions are added. In this way, whether static or scanning, for each detector position, intensity is collected simultaneously at a number of 2theta positions, affording a huge advance in detector speed.
Thanks to the small strip widths, 1D scanning and scanning have become the firm favorite for powder diffraction and a compact SAXS setup using ScatterX78. A large choice of PreFIX optics and monochromators are available to optimize intensity and resolution for every measurement.
In 2D mode, the raw scattering pattern is imaged directly on the detector. The intensity at each pixel is recorded separately. During scanning, the intensities of pixels with the same absolute position are added. The 2D scanning method brings the advantages of variable radius. The small pixel size of PANalytical’s hybrid detectors means that our 2D images have the best resolution on the market. The lack of detector noise means that very weak scattering can be detected with long exposure times, providing images that can compete in sensitivity with some of the best synchrotron results.
2D static and scanned images have proven popular for example in microdiffraction, GISAXS, SAXS, WAXS, and topography. Thanks to a choice of detectors and diffractometer radii, many applications can be covered on a single platform.
In 3D mode, a series of 2D frames are recorded under a set of changing conditions that constitutes the 3rd dimension. CT is a classic example of a 3D application, in which 2D absorption images (radiographs) are collected over a 360o range of rotation about the sample axis and combined to provide a transparent 3D view of the sample.