Low Tube Current Research Articles

Determination of the spectral intensity distribution of the incident beam in energy-dispersive X-ray diffractometry

The measurement of the spectral intensity distribution of the incident beam in energy-dispersive X-ray diffractometry has been examined by several methods. The spectral distribution estimated from the integrated intensity of a well defined reflection at several energies is the most reliable. Three direct measurements of the spectral distribution by a solid-state detector are also examined. Of these only the measurement at very low tube current can be used in structure factor determination, but the accuracy is about 5% even for strong reflections.

Correction for spectral artifacts in cross-sectional reconstruction from x rays.

A monoenergetic response correction is described which, along with adequate filtration, may be used to remove the spectral shift artifact encountered in three-dimensional reconstruction from x rays. Reconstructions were carried out by means of a convolution algorithm for simulated data using this method. These are compared with reconstructions obtained using fixed-length water-bath scans as a remedy for the special artifact. These studies suggest that the spectral artifact can be successfully eliminated from computerized cross-sectional scans without resorting to the use of the water bath while, at the same time, improving quantum statistics and/or permitting operation at a lower tube current.