Development of 2D dispersive device for XRF imaging spectrometer

Micro-XRF analysis provides us with elemental maps, which are very useful for understanding the samples under test. Usually, scanning-type elemental mapping is performed. That means, a sample stage is scanned to a fixed X-ray micro beam. XRF analysis is performed at the scanned points, leading to 2D elemental mapping. One of the drawbacks of this technique is the long acquisition time depending on the area being mapped and the lateral resolution required. Thus, projection-type elemental mapping has been studied. We have studied the projection type XRF imaging by using a straight polycapillary optic combined with an X-ray CCD camera. To obtain the elemental map, we applied a wavelength dispersive spectrometer (WDS). In this paper, we report a newly developed 2D dispersive device. The construction and analytical performance of this X-ray optic will be explained. INTRODUCTION Micro X-ray beams are obtained by using several types of X-ray focusing optics in the laboratory. For example, a recent advanced polycapillary focusing optic gives an X-ray micro beam that is 10 m in diameter by combining it with a micro focused X-ray tube. In micro-XRF, the micro X-ray beam irradiates the localized point on the sample, and then XRF analysis is performed at the localized region. In advanced materials and micro-structured devices, micro-XRF analysis is very useful for the analysis of contamination particles on the surfaces of devices. Another important application of micro-XRF is elemental mapping (Tsuji and Nakano, 2011). The sample stage is scanned with a fixed X-ray micro beam. XRF analysis is performed at different positions, leading to 2D XRF images. This technique gives XRF images for which the resolution depends in part on the size of the X-ray beam. However, one drawback of this technique is long acquisition times if the imaging area is large. Thus, projection-type XRF imaging has been studied. This method does not require a 228 Copyright ©JCPDS-International Centre for Diffraction Data 2012 ISSN 1097-0002