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.
METIS, the Mid-infrared Imager and Spectrograph for the Extremely Large Telescope (ELT), is one of the three first generation science instruments and about to complete its final design phase [1]. The Imager sub-system provides diffraction-limited imaging capabilities and low-resolution grism-spectroscopy in two channels: one covers the atmospheric LM bands with a field of view of 11x11 arcsec, and the second covers the N band, with a field of view of 14x14 arcsec. Both channels have a common collimator and a dichroic beam splitter dividing the light into two dedicated cameras and the corresponding detectors. In addition, the Imager provides a precise pupil re-imaging implementation allowing the positioning of high-contrast imaging masks for coronagraphic applications. The two channels are equipped with a HAWAII-2RG detector for LM-band and a GeoSnap detector for the N-band. We present the final optical design of the Imager in a summary, as well as the cryo-mechanical concept. The mechanical design gives an overview of the general design aspects and the analyses that demonstrate the approach how to deal with demanding stability and alignment requirements for high-contrast imaging. It further focuses on the design of individual units as e.g., on the GeoSnap detector mount and on the pupil re-imager. In addition, we exemplarily outline some of the key alignment and verification tasks, essential to guarantee the performance of the Imager.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.