Design of a 1k pixel Ge:Sb focal-plane array for far-IR astronomy

摘要

Development of large format, far infrared focal-plane arrays has been identified as a pressing need for futureastronomical instruments. In particular, array sizes as large as 128x128 with sensitivities equal to or better than 10-18W/√Hz are the goals to be achieved within the next fifteen years. As part of our continuing effort to further thistechnology, we are developing a 32x32 Ge:Sb photoconductor FPA with a CTIA cryogenic readout multiplexer. Anew, layered-hybrid architecture is employed to block the readout glow, improve heat dissipation and temperatureuniformity across the array, and alleviate the potential problems associated with the large CTE mismatch between theGe detector and the Si readout. This is the first 1k-pixel photoconductor FPA of its kind and is meant to be a pathfinderfor future large format FPAs. Based on the test results of a prototype 2x16 Ge:Sb array of similar design, we expect thesensitivity of this FPA to be as low as 10~(-18)W/√Hz. This paper presents the design, characteristics, and expectedperformance of this array.