We developed a python-based fluorescence analysis package (PyXRF) at the National Synchrotron Light Source II (NSLS-II) for the X-ray fluorescence-microscopy beamlines, including Hard X-ray Nanoprobe (HXN), and Submicron Resolution X-ray Spectroscopy (SRX). This package contains a high-level fitting engine, a comprehensive commandline/ GUI design, rigorous physics calculations, and a visualization interface. PyXRF offers a method of automatically finding elements, so that users do not need to spend extra time selecting elements manually. Moreover, PyXRF provides a convenient and interactive way of adjusting fitting parameters with physical constraints. This will help us perform quantitative analysis, and find an appropriate initial guess for fitting. Furthermore, we also create an advanced mode for expert users to construct their own fitting strategies with a full control of each fitting parameter. PyXRF runs single-pixel fitting at a fast speed, which opens up the possibilities of viewing the results of fitting in real time during experiments. A convenient I/O interface was designed to obtain data directly from NSLS-II’s experimental database. PyXRF is under open-source development and designed to be an integral part of NSLS-II’s scientific computation library.
In an ongoing effort to advance the state of the art in x-ray nanofocusing optics , multilayer Laue lens (MLL) [2,3] fabrication at NSLS-II has matured to include multi-gas reactive sputtering for stress and interfacial roughness reduction, which has recently led to a 70 micron thick single-growth MLL. Reactive sputtering was found to produce WSi2/Si multilayers with an accumulated film stress significantly lower than Ar-only deposition with identical growth conditions. Significant effort has been focused on the achievement of highly-stable gas mixing and process gas pressure measurement for multilayer growth and the problems faced along with implemented solutions will be discussed in detail. Proper layer thickness and placement throughout the stack presents a major obstacle to the fabrication of high-quality nanofocusing MLLs. Initial metrology of extremely thick MLLs by stitching many scanning electron microscope images was found to be greatly simplified by inclusion of marker labels within the stack.
Hard x-ray point focusing by two crossed multilayer Laue lenses is studied using a full-wave modeling approach. This study shows that for a small numerical aperture, the two consecutive diffraction processes can be decoupled into two independent ones in respective directions. Using this theoretical tool, we investigate adverse effects of various misalignments on the 2D focus profile and discuss the tolerance to them. We also derive simple expressions that describe
the required alignment accuracy.