Depending on the scientific question and the sample geometry, the following methods, amongst others, may be used:

• Powder X-ray diffraction (powder XRD) for phase identification and structural analysis of crystalline materials
• Grazing-incidence X-ray diffraction (GIXRD) for the investigation of crystalline phases and preferred orientations in thin films
• X-ray reflectometry (XRR) for the model-based determination of film thickness, density and interfacial roughness of suitable thin-film systems

Depending on the sample environment and the required measurement geometry, time-resolved, in situ or operando investigations can also be carried out.

In addition, we have equipment for small-angle X-ray scattering in transmission and grazing-incidence geometries (SAXS and GISAXS), GIWAXS and in-plane GID measurements, high-resolution X-ray diffraction and reciprocal space maps, as well as specialised transmission, capillary and texture measurements. Although the system is designed as a flexibly configurable multi-purpose platform, the configuration changes required for this involve extensive modifications, re-calibration and method-specific validation measurements. As this temporarily interrupts routine operations, such investigations can only be carried out on a case-by-case basis and with sufficient lead time.

Current configuration

The instrument is currently operated predominantly in a copper-based configuration for powder XRD, GIXRD and XRR:

• Generator: 3 kW generator with internal water-to-water cooling unit
• Goniometer: vertical ATLAS-θ/θ goniometer with non-coplanar detector arm
• X-ray source: ceramic Cu X-ray tube with line and point focus, maximum power 2.2 kW
• Radiation: Cu K_α1/2 radiation; suppression of K_β and white radiation by the Göbel mirror and, depending on the measurement configuration, by an additional Ni filter
• Wavelengths: λ(K_α1) = 1.5406 Å and λ(K_α2) = 1.5444 Å; the K_α1/K_α2 doublet is used in the routine configuration
• Primary optics: 60 mm Göbel mirror for generating a parallel beam, as well as interchangeable apertures, collimators and stray light shields
• Secondary optics: permanently installed motorised stray beam stop with axial and equatorial collimation via Soller collimators
• Detector: EIGER2 R 500K hybrid pixel area detector
• Sample positioning: compact motorised UMC sample stage for powder XRD and GIXRD, as well as a rotating 5-inch vacuum sample stage with a cutting aperture attachment for XRR measurements
• Control and analysis: DIFFRAC.MEASUREMENT, as well as DIFFRAC.EVA, DIFFRAC.TOPAS, DIFFRAC.LEPTOS and DIFFRAC.SAXS

Components for special configurations

In addition, the following components, amongst others, are available but are not routinely installed in the instrument:

• ceramic Mo X-ray tube with line and point focus, maximum power 3 kW
• Focusing 60 mm Göbel mirror for Mo radiation and Zr filter
• ACC2 Ge(004) double monochromator for high-resolution measurements with Cu-K_α1 radiation, typical beam divergence 0.0045°
• parallel PolyCap optics
• Motorised centric Euler cradle with Χ - and φ - axes and XYZ positioning
• Capillary sample stage
• evacuated flight path, as well as pinhole, UBC and small-angle collimators
• Sample stage and beam stops for GISAXS and GIWAXS measurements
• Special secondary optics for USAXS
• X-ray camera option, including camera mount

The equipment is used by several research groups at Paderborn University, as well as within the framework of scientific collaborations. Enquiries from other research groups at the university and from external research organisations are welcome.

Researchers interested in using the equipment may contact Prof. Dr Julia Linnemann to discuss the research question, the suitability of the samples and the possible measurement method. It would be helpful to provide brief details of

• the research question and the desired information
• the material and sample geometry
• the number of samples
• any expected phases or structures
• any specific requirements regarding the sample environment or measurement period

Depending on the research question, the work is carried out either as part of a scientific collaboration or as a supervised measurement. Independent use of the equipment requires appropriate training and authorisation.