Highly versatile laboratory X-ray scattering instrument enabling (nano-)material structure analysis on multiple length scales by covering a scattering vector range of almost five decades.

A compact laboratory X-ray scattering platform that uniquely enables for high-performance ultra-small-angle X-ray scattering (USAXS), small- and wide-angle X-ray scattering (SAXS/WAXS), and total scattering (atomic pair distribution function analysis; PDF) experiments was developed. It covers Bragg spacings from sub-Angstroms to 1.7 µm, thus allowing the analysis of dimensions and complex structures in (nano-)materials on multiple length scales. The accessible scattering vector q-range spans over almost five decades (qmin = 0.0036 nm-1, qmax = 215 nm-1), without any gaps. Whereas SAXS is suitable to characterize materials on a length scale of 1-100 nm, with USAXS, this range can be significantly extended to the micrometer range. On the other end, from WAXS and particularly from PDF measurements, information about the local atomic order and disorder can be obtained. The high performance, exceptional versatility, and ease-of-use of the instrument are enabled by a high-resolution 2-circle goniometer with kinematic mounts, a modular concept based on prealigned, quickly interchangeable X-ray components, and advanced detector technology. For USAXS measurements, a modified Bonse-Hart experimental setup with single crystal collimator and analyzer optics is used. SAXS/WAXS measurements are enabled by focusing optics, an evacuated beam path, and a 2D detector. For total scattering experiments, a high-energy X-ray source is used in combination with a hybrid pixel array detector that is based on a CdTe sensor for the highest counting efficiency. To ensure high resolution and sensitivity in these various applications, special care is taken to suppress any type of background scattering signal. The high resolution that can be achieved with the USAXS collimation system is demonstrated on a set of monodisperse, colloidal silica dispersions and derived colloidal crystals, with particle diameters in the range of hundreds of nanometers up to 1.6 µm. USAXS and SAXS results are shown to be consistent with those obtained by static light scattering (SLS) and dynamic light scattering. It is demonstrated that the obtainable USAXS data bridge the gap in q between SAXS and SLS. The capabilities of the instrument to acquire high-quality total scattering data for PDF analysis are demonstrated on amorphous SiO2 nanoparticles as well as on NaYF4 upconversion nanocrystals. To the best of our knowledge, it is for the first time that we present a single laboratory instrument that enables measurements of high-quality X-ray scattering data within such a wide q-range, by combining four complementary elastic X-ray scattering techniques. The modular design concept of the instrument allows for incremental improvements as well as to add more applications in the future.

High-performance small- and wide-angle X-ray scattering (SAXS/WAXS) experiments on a multi-functional laboratory goniometer platform with easily exchangeable X-ray modules.

Small-angle X-ray scattering (SAXS) is a well-established, versatile technique for the analysis of nanoscale structures and dimensions, e.g., in liquid dispersions, thin solid objects or powder samples. When combined with wide-angle X-ray scattering (WAXS), complementary information about the atomic structure can be obtained. SAXS experiments traditionally require dedicated instruments to achieve the desired angular resolution, sensitivity, stability, and speed of measurement. Here we demonstrate how a multi-functional laboratory goniometer platform, as widely being used for powder X-ray diffraction and for a variety of related techniques, can be configured with pre-aligned X-ray modules that enable advanced SAXS/WAXS experiments, without compromising the exceptional versatility of the instrument. Line and point collimation setups, as well as quick and easy switching between them, are readily possible. Key components are a detachable, evacuated beam path and a high-resolution, low-noise hybrid pixel area detector, in combination with a hardware interface design that allows to configure the instrument with different X-ray modules without the need for re-alignment. Software for SAXS data reduction and analysis was developed. The good SAXS/WAXS performance and the derived analytical results were verified on various test samples, such as gold nanoparticles, colloidal silica, liposomes, dilute protein solutions, and solid polymer samples. It is believed that this novel approach to SAXS/WAXS instrumentation will help to make this powerful structure analysis technique more widely accessible and affordable for multi-user laboratories.