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Proceedings Paper

Progress on development of UV photocathodes for photon-counting applications at NASA GSFC
Author(s): J. Stock; G. Hilton; T. Norton; B. Woodgate; S. Aslam; M. Ulmer
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Paper Abstract

The development of high quantum efficiency photemissive detectors is recognized as a significant advancement for astronomical missions requiring photon-counting detection. For solar-blind NUV detection, current missions (GALEX, STIS) using Cs2Te detectors are limited to ~10% DQE. Emphasis in recent years has been to develop high QE (>50%) GaN and AlGaN photocathodes (among a few others) that can then be integrated into imaging detectors suitable for future UV missions. We report on progress we have made in developing GaN photocathodes and discuss our observations related to parameters that effect efficiency and stability, including intrinsic material properties, surface preparation, and vacuum environment. We have achieved a QE in one case of 65% at 185 nm and are evaluating the stability of these high QEs. We also discuss plans for incorporating photocathodes into imaging and non-imaging sealed devices in order to demonstrate long term stability.

Paper Details

Date Published: 18 August 2005
PDF: 8 pages
Proc. SPIE 5898, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIV, 58980F (18 August 2005); doi: 10.1117/12.617517
Show Author Affiliations
J. Stock, Swales Aerospace (United States)
G. Hilton, Science Systems and Applications, Inc./NASA Goddard Space Flight Ctr. (United States)
T. Norton, Science Systems and Applications, Inc./NASA Goddard Space Flight Ctr. (United States)
B. Woodgate, NASA Goddard Space Flight Ctr. (United States)
S. Aslam, Muniz Engineering/NASA Goddard Space Flight Ctr. (United States)
M. Ulmer, Northwestern Univ. (United States)


Published in SPIE Proceedings Vol. 5898:
UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIV
Oswald H. W. Siegmund, Editor(s)

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