  We present a description of a new 1024x1024 Si:As array designed for
ground-based use from 5 - 28 microns. With a maximum well depth of 5e6
electrons, this device brings large-format array technology to bear on
ground-based mid-infrared programs, allowing entry to the megapixel realm
previously only accessible to the near-IR. The multiplexer design features
switchable gain, a 256x256 windowing mode for extremely bright sources, and it
is two-edge buttable. The device is currently in its final design phase at DRS
in Cypress, CA. We anticipate completion of the foundry run in the beginning of
2006. This new array will enable wide field, high angular resolution
ground-based follow up of targets found by space-based missions such as the
Spitzer Space Telescope and the Widefield Infrared Survey Explorer (WISE).
