Temperature sensitivity characterization of a silicon diode array spectrometer

High spectral resolution remote sensing devices are frequently used to quantify the flux of energy reflected from or transmitted through an optical medium. Their use requires careful calibration against a well-characterized standard. This study was conducted to characterize temperature sensitivity of a typical silicon-detector-based spectroradiometer, demonstrate the potential errors due to temperature effects, and present a methodology to correct for temperature-induced errors. Three Spectron Engineering SE590 units were independently evaluated under varying temperatures at three separate institutions. A procedure for correcting calibration coefficients (radiance/count) as a junction of temperature and wavelength was developed and applied. The evaluation showed that at wavelengths between 390 nm and 940 nm the calibration coefficients differed from each other by less than 5% among all ambient temperatures. At 1000 nm, the calibration coefficient decreases about 5% going from 25°C to 35°C and increases about 25% going from 25°C to 0°C. Wavebands below 390 nm responded chaotically to temperature. At any given wavelength above 940 nm the change in calibration coefficient value was a nearly linear function of temperature, an indication that a simple temperature correction can be applied. Calibration coefficients were linearly interpolated for each waveband greater than 940 nm at temperatures between temperature extremes imposed upon the instruments during the experiments. Linearly interpolated calibration coefficients were found to be within 4% of actual values. Users of silicon-detector-based spectroradiometers should be aware of potential errors in data due to temperature effects.