Euclid: methodology for derivation of IPC-corrected conversion gain of nonlinear CMOS APS

Abstract

We introduce a fast method to measure the conversion gain in complementary metal-oxide-semiconductor (CMOS) active pixel sensors (APS), which accounts for nonlinearity and interpixel capacitance (IPC). The standard ``mean-variance'' method is biased because it assumes that pixel values depend linearly on the signal, and existing methods to correct for nonlinearity still introduce significant biases. While current IPC correction methods are prohibitively slow for a per-pixel application, our new method uses separate measurements of the IPC kernel to calculate the gain almost instantaneously. Using test data from a flight detector of the ESA Euclid mission, the IPC correction recovers the results of slower methods with 0.1% accuracy. The nonlinearity correction ensures that the estimated gain is independent of signal, correcting a bias of more than 2.5%.

Affiliated Institutions

• European Space Agency FR
• Université Paris Cité FR
• Centre National d'Études Spatiales FR
• Institut de Physique des 2 Infinis de Lyon
• Institut d'Astrophysique Spatiale FR
• Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules FR
• Institut d'Astrophysique de Paris FR
• Astrophysique, Instrumentation et Modélisation FR
• Institute of Nuclear Physics of Lyon FR
• Centre de physique des particules de Marseille FR
• Château Gombert FR
• Laboratoire d’Astrophysique de Marseille FR
• Laboratoire AstroParticule et Cosmologie FR
• CEA Paris-Saclay FR
• Commissariat à l'Énergie Atomique et aux Énergies Alternatives FR

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