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Proceedings Paper

Intrapixel sensitivity in NIR detectors for NGST
Author(s): Utkarsh Sharma; Donald Frank Figer; Bernard J. Rauscher; Michael W. Regan; Louis E. Bergeron; Jesus C. Balleza; Robert H. Barkhouser; Russell Pelton; Mike Telewicz; Paul Stemniski; Sungsoo Kim; Gretchen R. Greene; Stephan Robert McCandliss; Anand Sivaramakrishnan; Thomas Reeves; Hervey S. Stockman
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Paper Abstract

Intra-Pixel Sensitivity (IPS) is defined as the spatially varying response of the pixel to incoming flux. IPS plays a crucial role when the Point-Spread Function (PSF) is critically, or under-, sampled. Variations in IPS lead to photometric and astrometric errors. The Next Generation Space Telescope (NGST) requires high quality photometry and astrometry, so an accurate estimation of the IPS function is necessary for a successful NGST mission. Photo-electrons generated in a pixel may be detected in the depletion region (detection of the flux) of the same pixel, or might diffuse and end up in the microstructure of the detector, the electric field distribution therein, wavelength of the incident radiation, and diffusion processes of the excess charge carriers generated determines the IPS function of a pixel that can vary from pixel to pixel. The total detected flux is proportional to the convolution of the PSF and the IPS function. If we approximate the profile of the PSF, then the problem of determining the IPS function reduces to deconvolving using the experimentally obtained Sensitivity variation profile and the calculated PSF. We aim to obtain a highly undersampled PSF, scan it over a single pixel on a grid of 10 x 10 points, and retrieving IPS function using deconvolution. We present our results, experiment design, and the scope of further work, using an NGST detector, to estimate the IPS function at various wavelengths.

Paper Details

Date Published: 5 March 2003
PDF: 7 pages
Proc. SPIE 4850, IR Space Telescopes and Instruments, (5 March 2003); doi: 10.1117/12.461554
Show Author Affiliations
Utkarsh Sharma, Johns Hopkins Univ. (United States)
Space Telescope Science Institute (United States)
Donald Frank Figer, Space Telescope Science Institute (United States)
Bernard J. Rauscher, Space Telescope Science Institute (United States)
Michael W. Regan, Space Telescope Science Institute (United States)
Louis E. Bergeron, Space Telescope Science Institute (United States)
Jesus C. Balleza, Space Telescope Science Institute (United States)
Robert H. Barkhouser, Johns Hopkins Univ. (United States)
Russell Pelton, Johns Hopkins Univ. (United States)
Mike Telewicz, Space Telescope Science Institute (United States)
Paul Stemniski, Space Telescope Science Institute (United States)
Sungsoo Kim, Space Telescope Science Institute (United States)
Gretchen R. Greene, Johns Hopkins Univ. (United States)
Stephan Robert McCandliss, Johns Hopkins Univ. (United States)
Anand Sivaramakrishnan, Space Telescope Science Institute (United States)
Thomas Reeves, Johns Hopkins Univ. (United States)
Hervey S. Stockman, Space Telescope Science Institute (United States)


Published in SPIE Proceedings Vol. 4850:
IR Space Telescopes and Instruments
John C. Mather, Editor(s)

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