Infrared Arrays at the European Southern Observatory

Abstract

This paper gives an overview of infrared array detectors which have been tested and used at ESO. The performance of arrays using Reticon type readouts, CCD readouts and switched FET multiplexers have been evaluated for both InSb and Hg_1-xCd_xTe detectors. Performance limitations specific to the NICMOS3 256 x 256 Hg_1-xCd_xTe detector installed in the ESO infrared array camera IRAC2 are addressed. The first test results with a high well capacity SBRC 256 x 256 InSb array are also presented.

Advanced readout techniques for image sharpening tested on a 2.2-m telescope are discussed briefly. A new generation of instruments being built for the VLT, the very large telescope project of ESO, is designed to house large format 1024 x 1024 IR arrays. A fast data acquisition system is currently being developed at ESO. The system is capable of handling the high data rates generated in the thermal infrared by large format low well capacity arrays. It can also cope with the low read noise required for flux levels of ≤ one photon/sec. It will first be installed in ISAAC, the Infrared Array Camera and Spectrometer built for the VLT (Moorwood 1993). The present status of both the detector developments and the data acquisition system is reviewed.