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Proceedings Paper

CCD riddle: a) signal vs time: linear; b) signal vs variance: non-linear
Author(s): Mark Downing; Dietrich Baade; Peter Sinclaire; Sebastian Deiries; Fabrice Christen
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Paper Abstract

Photon transfer curve is one of the most valuable tools for calibrating, characterizing, and optimizing the performance of CCDs. Its primary purpose is to determine the conversion gain of the CCD system, from which many of the other performance parameters such as read noise, dark current, QE, full well etc. are determined. Recent measurements on CCDs from different manufacturers have revealed that the photon transfer curve is non-linear (in excess of 15%) with the variance progressively becoming less at high signal levels than that predicted by simple photon shot noise. The puzzling thing is that the signal linearity is excellent and unaffected. This paper reports on the investigation which has isolated the source of the non-linearity to the CCD image area. Additionally, spatial autocorrelation analysis shows that the mechanism behind the non-linearity is due to spreading or sharing of charge between pixels in the image area. The authors only have a description of the phenomenon and invite all to help with an explanation.

Paper Details

Date Published: 15 June 2006
PDF: 11 pages
Proc. SPIE 6276, High Energy, Optical, and Infrared Detectors for Astronomy II, 627609 (15 June 2006); doi: 10.1117/12.671457
Show Author Affiliations
Mark Downing, European Southern Observatory (Germany)
Dietrich Baade, European Southern Observatory (Germany)
Peter Sinclaire, ESO La Silla Observatory (Chile)
Sebastian Deiries, European Southern Observatory (Germany)
Fabrice Christen, Kapteyn Astronomical Institute (Netherlands)

Published in SPIE Proceedings Vol. 6276:
High Energy, Optical, and Infrared Detectors for Astronomy II
David A. Dorn; Andrew D. Holland, Editor(s)

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