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The WFI instrument is designed for high-resolution X-ray imaging and spectroscopy with a large field of view. A movable mirror focuses the X-rays onto the focal plane detectors of the WFI. For design development of the instrument, structural analysis is performed from early project phases. The WFI project has entered phase B and the preliminary design is evolving towards a more detailed design including interface definitions. The focal plane of WFI consists of two detectors: Large Detector Array (LDA) and Fast Detector (FD). The LDA assembly is used for main observation modes, whereas FD is for very bright point sources. The complexity of the LDA design is due to the fact that it has to be compliant to contradictory requirements. Its sensors have to be thermally decoupled from the structure, but with a high stiffness to avoid relative displacement and deformation of sensitive components, e.g. bond wires. The LDA has an active area that is as large as ≈14x14 cm2 but the thermal gradient across it shall be below 2.5-3K. The LDA is optimized with respect to mechanical requirements for launch loads and operational conditions in space. In order to minimize mass while withstanding thermo-mechanical, static and dynamic loads, various design studies have been carried out. With the aim to develop a design, which meets all structural and functional requirements, various structural analyses are performed. In this paper, the structural design studies and the preliminary analysis results of the WFI Large Detector Array are presented.

The WFI (Wide Field Imager) instrument is planned to be one of two complementary focal plane cameras on ESA's next X-ray observatory Athena. It combines unprecedented survey power through its large field of view of 40 arcmin x 40 arcmin together with excellent count-rate capability (>= 1 Crab). The energy resolution of the silicon sensor is state-of-the-art in the energy band of interest from 0.2 keV to 15 keV, e.g. the full width at half maximum of a line at 6 keV will be

The Mercury Imaging X-ray Spectrometer (MIXS) is an instrument on board of the 5th ESA cornerstone mission BepiColombo. This Spectrometer comprises two instruments for imaging x-ray spectroscopy of the Mercury surface. The detector plane arrays (DPA) for the energy and spatial resolved detection of x-rays are based on DEPFET (Depleted P-channel FET) macropixel detectors with 64×64 pixel each and 300×300 μm 2 pixel size. The MIXS target energy band is from 0.5 to 7 keV with an energy resolution better than 200 eV at 1 keV at mission end. This allows to access the Fe-L line at about 0.7 keV, which was not accessible to previous instruments, and to separate the x-ray lines of the elements of interest. Before a detector chip is integrated into a detector module, it is electrically pre-characterized in order to select only the best chips for the complex and time-consuming integration. The high degree of complexity of the integration process comes from the need to thermally decouple the detector chip from its readout and steering ASICs by a sophisticated mechanical structure, due to the limited amount of cooling power available for the instrument. After the spectroscopic characterization of the detector modules, the flight and flight spare detectors were calibrated at the PTB (Physikalisch-Technische Bundesanstalt) beamlines at the BESSY-II synchrotron. We report on the pre-characterization, integration, qualification and calibration of MIXS flight and flight spare detectors, which is now successfully completed.