14 September 2007 Conversion gain non-linearity and its correction in hybridised near infrared detectors
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The conversion gain in hybridised near infrared detectors with Source Follower per Detector unit cells changes non-linearly as the signal integrates on the junction capacitance of the detector diodes[1,2]. However, the non-linearity in the measured conversion gain as calculated from the conventional photon transfer technique (~15% in VIRGO-2K for example) is higher than the non-linearity noticed at the detector output (~4% in the same detectors). This paper presents experimental data from the VIRGO-2K, Aladdin-III and Hawaii-1RG detectors which is used to highlight this discrepancy and thus show the shortcomings of the use of the photon transfer technique with such non-linear detectors. The mechanism for the changing detector node capacitance with integrating signal is explained. A method for correcting the measured conversion gain to account for this non-linearity has been implemented on the data from the same detectors and will be presented. If not corrected, this non-linearity can be another source of error that could cause an over-estimation of the detector performance parameters (as is the case with the inter-pixel capacitance).
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Nagaraja Bezawada, Nagaraja Bezawada, Derek Ives, Derek Ives, David Atkinson, David Atkinson, "Conversion gain non-linearity and its correction in hybridised near infrared detectors", Proc. SPIE 6690, Focal Plane Arrays for Space Telescopes III, 669005 (14 September 2007); doi: 10.1117/12.732454; https://doi.org/10.1117/12.732454

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