Daniel F. Puentes and Jose L. Bañuelos
GI-SAXS and XR are experimental techniques for investigating the nanoscale structure and composition of thin films: GI-SAXS gives information about the in-plane structure of nanotextured films, and XR gives the information on how the nanostructure changes as a function of depth. Such studies are traditionally carried out at synchrotron radiation facilities so this capability will improve access to these techniques for surface scientists in the region. A Labview program was developed to control a sample stage that is able to precisely orient a sample and control the x-ray beam incidence angle for use in GI-SAXS and XR studies on the Xeuss 2.0 HR SAXS system in the UTEP department of physics. The program takes a user-specifed angular range, total number of points for the desired resolution, and duration of x-ray collection time per point for the experiment as inputs. The program outputs the start time, end time, and stage position information into a graphical display and a log file to synchronize with the x-ray detector data. Tests of this new experimental setup as well as the data processing routines to extract standard reflectivity curves have been done. A 50-100 nm glassy carbon thin film deposited on a sapphire substrate is being used to test the XR setup. Future tests will involve studying the lateral structure of the film (using GI-SAXS) as well as the behavior of complex fluids at the fluid-solid interface with applied electric fields. Details of the control program, x-ray techniques, and preliminary measurements will be presented.