Modal Analysis Of Sprite Noise Spectra

The detector noise is the key limit to any imaging system. The unique design of signal processing in the element (SPRITE) detectors provides measurable signal to noise improvement over ordinary detectors. The analysis and description of the noise in this type of detector is complicated by the fact that transport phenomena filter the noise spectra prior to readout. Previous analyses of the noise behavior used an approximate solution to the charge transport problem to produce expressions for the noise PSD, and yield predictions of a flat PSD at low frequencies. Measurements of real devices show a large 1/f behavior at low frequencies, but this has always been attributed to contact effects. In this paper, we use the results of the eigenmode solution to the transport problem to derive the PSD of the noise. We show that this analysis produces noise PSDs that have a 1/f dependence caused simply by the operation of the transport processes. The result is then coordinated with the similarly obtained signal response MTF to produce the frequency dependent signal to noise ratio. These are computed over several ranges of detector parameters with the intent of revealing their optimum values