Abstract
The work contained in this thesis is concerned with the performance of infrared integrating detector arrays, within the context of astronomical spectroscopy.
A linear array of thirty-two InSb photo diodes is investigated. It is found to exhibit good capacitance and dark current uniformity across the array. By applying the principle of charge conservation to the multiplexed readout arrangement of this device, the signal response of the detector to different levels of illumination is derived. It is found from this, and confirmed experimentally, that the device has a highly linear radiation response over a range of reverse biases.
The interaction between dark current and photo-current is studied,primarily by the application of a simple model. The results indicate that the effective signal gain of a detector can vary in the situation where dark current dominates the discharge processes, since in this instance accurate dark current subtraction becomes difficult.
The predictions of the model are compared with experiments performed on two integrating arrays; one under study in the laboratory,and the other installed in the low background environment of a cooled grating spectrometer. Finally, suggestions are presented of ways of avoiding this problem, the simplest of which involves utilizing, where possible, low dark current detector materials.
The importance of achieving good dark current uniformity with arrays is stressed, since this will improve the ability to flat-field faint object spectra.
To illustrate the importance of these devices, infrared spectra obtained with array detectors, covering a range of astronomical objects,are presented and discussed.
