Influences of Array Parameters on Instrument Calibration

Abstract

One of the advantages of solid-state detector arrays is that they are intrinsically stable, both geometrically and in terms of the basic properties of the electronic building blocks (photodiodes or photogates, shift registers, amplifiers, etc.) of which they are constructed. Their stability arises because doping densities, carrier mobilities, device dimensions, etc., are not normally expected to change with time. However, it will be seen in the following discussion that several of the key performance parameters depend on operating conditions (e.g., temperature, applied voltages, clocking rates, and illumination conditions) so that unless these conditions are well defined, the device performance can vary. For this reason there is an important need for frequent calibration of array instrumentation (and for data correction) when radiometric or wavelength accuracy is required. It will also be seen that the most important parameters for the majority of applications in the UV, visible, and near-infrared can be calibrated by a simple arrangement of stable light source and optical filters, thus making the provision of calibration artifacts feasible and relatively straightforward.