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For several years, the R&D group at KPNO has been evaluating the performance of a 32 X 1 InSb CID array obtained from General Electric (Syracuse) under background conditions anticipated for ground-based astronomical spectroscopic applications. The array, consisting of 100 pm square pixels on 125 pm centers, is intended for use in a cryogenic grating spec-trometer over the range 1.3 - 5.2 pm, with resolving power X/n -100 - 1000. To summarize the results of this evaluation12 i , it was found that an operating temperature -15 K would permit the MOS silicon scanner to operate reliably (but with changes in procedure from 77 K operation) and reduce the thermal dark current to negligible values. Quantum efficiencies measured in the laboratory under these operating conditions ranged from -0.8 at 2.2 pm to 0.25 at 4.7 pm. The most serious problem encountered with this array is the significant delay in output response to incident flux under conditions of low background. This "response lag" could present linearity problems in spectroscopic applica-tions where the integration time is limited by a strong spectral feature or by the thermal background at the long wavelength end of the spectral region being measured. In the summer of 1983, the array was sent to GE for repair of the scanner; in the course of this repair, four dead pixels were removed from the readout sequence and additional CID pixels at one end of the array were connected to the scanner. Thus, the new 33-element scanner reads out a linear array subtending 37 pixels, with pixels 4, 15, 19, and 21 missing from the sequence. After this repair was completed, the array was mounted in a cryostat for an evaluation of its performance as an imager through broadband photometric filters. This paper will summarize the imaging test and further experiments on the response lag problem and will conclude with some initial results with the array operating in the cryogenic grating spectrometer.
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