X-ray analysis with high-flux MetalJet sources

To continue advanced research in the hard X-ray regime > 10 keV at HZB, which is carried out so far at the materials science beamline EDDI@BESSY II, two local measuring stations equipped with high-flux liquid-metal-jet sources are established and will be operated within the X-ray corelab. Both X-ray facilities will be equipped with various easy-to-swap sample environments such as diffractometer systems, heating stations, mechanical load devices and deposition chambers, which allow for fast in-situ and ex-situ experiments in different fields of energy and materials research. The focus of experimental methods provided for

  • in-house POF-relevant research in the field of energy materials,
  • external user groups from national and international scientific institutions, and
  • industry

will be on the analysis of phase formation, residual stresses, microstructure, and texture in complex thin film systems and technical components. The main scientific objectives are the development and application of advanced measuring and data evaluation techniques which exploit the specific features of the X-ray spectrum emitted by the liquid-metal-jet source. Making use of the strong characteristic Kα lines of Ga and In at 9 keV and 24 keV, respectively, as well as of the white bremsstrahlung spectrum will allow for simultaneous angle- and energy-dispersive diffraction and fluorescence experiments.

X-ray Lab for real-time film growth, residual stress and microstructure analysis

The in-situ X-ray Lab (IXLab) at EMIL in Adlershof is dedicated to the study of reactive growth processes of functional thin films as well as to residual stress and microstructure analysis. For the analysis of time-critical reaction processes such as phase formations and microstructure changes, the Ga-Kα (9.2 keV) and In-Kα (24.2 keV) lines of the metal-jet X-ray source are used for angle-dispersive X-ray diffraction (ADXRD). An X-ray area detector allows to record diffraction rings within a few seconds (see Fig. 1), which provides sufficient time resolution for the investigation of various types of solid state reactions in thin films [1,2,3]. For residual stress analysis by energy-dispersive X-ray diffraction (EDXRD) [4], continuous polychromatic X-ray radiation up to 160 keV generated by bremsstrahlung is utilized.

IXLab: MetalJet setup and measured diffraction rings

Figure 1: In-situ X-ray Lab (IXLab) at EMIL in Adlershof. Left: Pilatus 1M detector, in-situ PVD chamber for the real-time analysis of compound semiconductor film growth, Excillum MetalJet X-ray source with a maximum voltage of 160 kV. Right: Diffraction rings and integrated intensities (inset) from a Cu(In,Ga)Se2 film recorded by the Pilatus 1M detector within 10 seconds.

To be able to switch between in-house research, external user research, and industry research, the sample environment can be exchanged with the help of a modular mounting stage. For the analysis of film formation processes during film deposition [1,2] or during annealing under reactive or inert atmospheres [3], tailor made in-situ process chambers are employed (see Fig. 1). For residual stress [4] and texture analysis, an Eulerian cradle based diffractometer setup with integrated x-y-z translation table can be mounted.

[1] Rodriguez-Alvarez, et al. Adv. Energy Mater. 3, 1381-1387 (2013), doi: 10.1002/aenm.201300339.
[2] Mainz, et al. Energy Environ. Science 9, 1818-1827 (2016), doi: 10.1039/c6ee00402d.
[3] Mainz, et al. Nature Communications 5, 3133 (2014), doi: 10.1038/ncomms4133.
[4] Klaus, C. Genzel, J. Appl. Chryst. 50, 252 (2017), doi: 10.1107/S1600576716020598.

X-ray Lab for diffraction and imaging

The metal jet X-ray source at Lise-Meitner-Campus in Wannsee generates white X-rays up to 70 keV on a liquid anode material which consists of a Ga-In alloy. The primary beam spectrum consists of Bremsstrahlung which is superimposed by the characteristic emission lines of Ga (9.2 keV) and with a minor contribution of In (24.2 keV). Thus, the source is suitable for many applications and measurement methods. The instrument concept is modular to enable energy- and angular-dispersive diffraction modes for residual stress, texture and microstructure determinations in the surface zone of materials. For this purposes the instrument is equipped with a sample table consisting of a two-circle HUBER diffractometer and an x-y-z translation unit. The sample stage is made to carry heavy loads and, thus, allows for further sample environment equipment, e.g. furnaces and stress rigs. Moreover, an Eulerian cradle including a local x-y-z-stage is available for further sample manipulation (see Fig. 2a). An option for beam focusing is currently under development.

MetalJet setup in Wannsee

Figure 2: (a) Excillum MetalJet X-ray source with 70 kV accelerating voltage equipped with a Huber diffractometer, an Eulerian cradle and a Ge multi-channel analyser. (b) Synchrotron setup for combined imaging-diffraction experiments which should be adapted to the lab.