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Proceedings Paper

Read noise for a 2.5µm cutoff Teledyne H2RG at 1-1000Hz frame rates
Author(s): Roger M. Smith; David Hale
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Paper Abstract

A camera operating a Teledyne H2RG in H and Ks bands is under construction at Caltech to serve as a near-infrared tip-tilt sensor for the Keck-1 Laser Guide Star Adaptive Optics system. After imaging the full field for acquisition, small readout windows are placed around one or more natural guide stars anywhere in the AO corrected field of view. Windowed data may be streamed to RAM in the host for a limited time then written to disk as a single file, analogous to a “film strip”, or be transmitted indefinitely via a second fiber optic output to a dedicated computer providing real time control of the AO system. The various windows can be visited at differing cadences, depending on signal levels. We describe a readout algorithm that maximizes exposure duty cycle, minimizes latency, and achieves very low noise by resetting infrequently then synthesizing exposures from Sample Up The Ramp data. To illustrate which noise sources dominate under various conditions, noise measurements are presented as a function of synthesized frame rate and window sizes for a range of detector temperatures. The consequences of spatial variation in noise properties, and dependence on frame rate and temperature are discussed, together with probable causes of statistical outliers.

Paper Details

Date Published: 25 September 2012
PDF: 15 pages
Proc. SPIE 8453, High Energy, Optical, and Infrared Detectors for Astronomy V, 84530Y (25 September 2012); doi: 10.1117/12.927148
Show Author Affiliations
Roger M. Smith, California Institute of Technology (United States)
David Hale, California Institute of Technology (United States)

Published in SPIE Proceedings Vol. 8453:
High Energy, Optical, and Infrared Detectors for Astronomy V
Andrew D. Holland; James W. Beletic, Editor(s)

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