Development of confocal 3D micro-XRF spectrometer with dual Cr-Mo excitation

A new 3D micro-XRF instrument based on a confocal setup using two independent polycapillary x-ray lenses and two x-ray sources (Cr and Mo targets) was developed. A full polycapillary x-ray lens was attached to each x-ray tube. Another half polycapillary lens was attached to a silicon drift x-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The depth resolutions that were evaluated by use of a 10-mu m thick Au foil were approximately 90 mu m for the x-ray energy of Au L alpha. The effects of the dual Cr-Mo x-ray beam excitation were investigated. It was confirmed that the XRF intensity of light elements was increased by applying the Cr-target x-ray tube in a confocal configuration. In the proposed confocal configuration, 3D elemental mapping of the major elements of an amaranth seed was performed nondestructively at ambient air pressure. Each element of the seed showed different mapping images in the different depth layers. Copyright (c) 2007 John Wiley & Sons, Ltd.