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Steward's Imaging Technology Laboratory Delivers More Than 100 CCDs For The LSST Telescope

The University of Arizona has completed delivery of over 100 science-grade 4kx4k Charge-Coupled Device (CCD) image sensors for the Large Synoptic Survey Telescope (LSST). This work was performed at the UA Imaging Technology Laboratory (ITL). The sensors are among the most demanding ever produced in terms of quantum efficiency, readout speed, and surface flatness. ITL had previously delivered a set of 4kx2k wavefront sensors which will also be used in the LSST focal plane. Both sensors were designed by Semiconductor Technology Associates, Inc. in California. The Imaging Technology Laboratory is directed by Dr. Michael Lesser and is a research group within the University's Steward Observatory. Financial support for LSST comes from the National Science Foundation (NSF) through Cooperative Agreement No. 1258333, the Department of Energy (DOE) Office of Science under Contract No. DE-AC02-76SF00515, and private funding raised by the LSST Corporation. The NSF-funded LSST Project Office for construction was established as an operating center under management of the Association of Universities for Research in Astronomy (AURA). The DOE-funded effort to build the LSST camera is managed by the SLAC National Accelerator Laboratory (SLAC).

Michael Lesser of ITL has graciously sent us three photos and explanations. 

Photo 1 (Click to enlarge) 

This photo shows the four liquid nitrogen cooled Dewars used for testing the science and wavefront sensors at ITL.  During the project’s production phases, two sensors were often characterized each day, with the other dewars warming up or cooling down for subsequent testing.

Photo 2 (click to enlarge)

An LSST STA4400 2kx4k Curvature Wavefront CCD sensor on its aluminum test tower.  The silicon CCD is mounted on a gold-plated silicon-aluminum alloy chosen for its excellent thermal characteristics. These sensors will be located in the “LSST corner rafts” and are used to provide feedback to the telescope’s active optics system.

Photo 3 (click to enlarge)

An LSST STA3800 4kxk4k CCD sensor undergoing final metrology inspection on a VIEW Summit 600 Coordinate Measuring Machine.  The surface flatness of the sensors is typically less than 4 microns peak-to-valley. Every sensor produced underwent electro-optical and metrological characterization before delivery.