Submicron X-ray diffraction

At the Advanced Light Source in Berkeley we have instrumented a beam line t hat is devoted exclusively to X-ray micro-diffraction problems. By micro-di ffraction we mean those classes of problems in Physics and Materials Scienc e that require X-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron-siz ed aluminum metal grains buried under a silicon dioxide insulating layer. T he resulting Laue pattern is collected on a large area CCD detector and aut omatically indexed to yield the grain orientation and deviatoric (distortio nal) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam. which allows monochromatic light to illumin ate the same part of the sample. Measurement of the diffracted photon energ y allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total st rain/stress tensor (6 components) inside each sub-micron-sized illuminated volume of the sample. (C) 2001 Elsevier Science B.V. All rights reserved.