Hard x-ray nanoprobe facility at the National Synchroton Light Source II

摘要: In scanning x-ray microscopy beamlines (such as that illustrated in Figure 1), monochromatic x-rays are focused to produce a nanobeam. X-ray imaging can be performed by scanning a sample across the focused beam, and the resulting x-ray signals are collected to visualize (with the use of a variety of contrast mechanisms) elemental, structural, and chemical details of the sample. Fluorescent x-rays, for example, are emitted by excited electrons in the sample and provide a unique fingerprint of its elemental composition. Bragg-diffracted x-rays yield detailed information on the crystalline phase, crystallite (ie, grain) orientation, and strain distribution. To obtain comprehensive structural and chemical images of a sample, scanning x-ray instruments must be capable of making simultaneous measurements of these different signal types.