CRYOGENIC READOUT ELECTRONICS AND TECHNOLOGY FOR FIRSTS STRESSED ARRAY

The ESA satellite ''FIRST'' (Far Infrared and Submillimeter Space Tele scope) is scheduled for launched in 2005. It is a successor to the IRA S and ISO satellites, and it should outperform them in terms of imagin g wavelength (the 100 mu m to 1 mm band), focal plane size, angular re solution and sensitivity. One major candidate for the focal plane inst rument is based on stressed Germanium-Gallium (Ge:Ga) detectors. For l ow leakage operation, these detectors should be operated at 1.6 Kelvin , and the closely coupled readout electronics should be operated at th e same temperature. In this paper we describe the electrical and envir onmental constraints of the design of the readout electronics for the 1616 pixel array. These specifications cannot be met with the readout circuits from the earlier ISOPHOT instruments. New circuits and ampli fication techniques and a new generation of cryogenic CMOS technology is needed.