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METIS, the Mid-infrared ELT Imager and Spectrograph for the Extremely Large Telescope (ELT), is one of the three firstgeneration science instruments, it has passed final design [1],[2] and is midway the Manufacturing, Assembly, Integration and verification (MAIV) phase. The Imager will be completely assembled and tested at MPIA in Heidelberg, Germany, before integration into the METIS instrument in Leiden, Netherlands. The Imager sub-system provides diffraction-limited imaging capabilities and low-resolution grism spectroscopy in two channels: the first covers the atmospheric L&M bands with a field of view of 11x11 arcsec, the second covers the N band, with a field of view of 14x14 arcsec. The two channels are equipped with a HAWAII-2RG detector for LM band and a GeoSnap detector for the N band, respectively [3],[5]. Challenging requirements suitable for high contrast imaging require a thorough integration and verification, particularly considering the size, complexity and the operating temperature of the instrument. Virtually, all components and units are in production or are already finished. The integration and verification of these units follow an MAIV plan including a detailed alignment scheme. The AIV part consists of three different phases: acceptance tests of components, alignment tasks, and verification of requirements. A dedicated test cryostat has been developed for the end-to-end verification to guarantee a smooth integration into the METIS instrument. Here, we present this MAIV process and describe in detail exemplary individual tasks of each phase to demonstrate the complexity of this stage of development and the managing of the challenging procedures. We also describe the tools and the corresponding setups used in the laboratory to execute the various tests, and the application of interferometric measurements at cryogenic conditions.
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