The Dark Energy Survey Camera focal plane array will consist of 62 2k x 4k CCDs with a pixel size of 15 microns and a silicon thickness of 250 microns for use at wavelengths between 400 and 1000 nm. Bare CCD die will be received from the Lawrence Berkeley National Laboratory (LBNL). At the Fermi National Accelerator Laboratory, the bare die will be packaged into a custom back-side-illuminated module design. Cold probe data from LBNL will be used to select the CCDs to be packaged. The module design utilizes an aluminum nitride readout board and spacer and an Invar foot. A module flatness of 3 microns over small (1 sqcm) areas and less than 10 microns over neighboring areas on a CCD are required for uniform images over the focal plane. A confocal chromatic inspection system is being developed to precisely measure flatness over a grid up to 300 x 300 mm. This system will be utilized to inspect not only room-temperature modules, but also cold individual modules and partial arrays through flat dewar windows.

Date Published: 5 June 2006
PDF: 10 pages
Proc. SPIE 6276, High Energy, Optical, and Infrared Detectors for Astronomy II, 627608 (5 June 2006); doi: 10.1117/12.672505

Published in SPIE Proceedings Vol. 6276:
High Energy, Optical, and Infrared Detectors for Astronomy II
David A. Dorn; Andrew D. Holland, Editor(s)