Gain sag in the FUV detector of the Cosmic Origins Spectrograph

David J. Sahnow; Cristina Oliveira; Alessandra Aloisi; Philip E. Hodge; Derck Massa; Rachel Osten; Charles Proffitt; Azalee Bostroem; Jason B. McPhate; Stéphane Béland; Steven N. Osterman; Steven V. Penton

doi:10.1117/12.893989

13 September 2011 Gain sag in the FUV detector of the Cosmic Origins Spectrograph

David J. Sahnow, Cristina Oliveira, Alessandra Aloisi, Philip E. Hodge, Derck Massa, Rachel Osten, Charles Proffitt, Azalee Bostroem, Jason B. McPhate, Stéphane Béland, Steven N. Osterman, Steven V. Penton

Author Affiliations +

Proceedings Volume 8145, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XVII; 81450Q (2011) https://doi.org/10.1117/12.893989
Event: SPIE Optical Engineering + Applications, 2011, San Diego, California, United States

Abstract

The Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) uses a large-format cross delay line (XDL) detector in its Far Ultraviolet (FUV) channel. While obtaining spectra, light falls non-uniformly on the detector due to the optical design and the spectral properties of the object being observed; in particular, bright emission lines from geocoronal Lyman-alpha can fall on the detector in more than 20 locations. As a result, some areas of the detector have received a much greater exposure than others. This non-uniform illumination has led to a time- and position-dependent change in the gain of the microchannel plates, which causes variations in the overall detector performance. We will discuss the effects of this gain sag on the science data, and discuss mitigation strategies which are being implemented in order to maximize the detector lifetime.

Citation Download Citation

David J. Sahnow, Cristina Oliveira, Alessandra Aloisi, Philip E. Hodge, Derck Massa, Rachel Osten, Charles Proffitt, Azalee Bostroem, Jason B. McPhate, Stéphane Béland, Steven N. Osterman, and Steven V. Penton "Gain sag in the FUV detector of the Cosmic Origins Spectrograph", Proc. SPIE 8145, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XVII, 81450Q (13 September 2011); https://doi.org/10.1117/12.893989

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available