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Proceedings Paper

Results from Cs activated GaN photocathode development for MCP detector systems at NASA GSFC
Author(s): Timothy J. Norton; Bruce E. Woodgate; Joseph Stock; George Hilton; Melville P. Ulmer; Shahid Aslam; R. D. Vispute
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Paper Abstract

We describe the development of high quantum efficiency UV photocathodes for use in large area two dimensional microchannel plated based, detector arrays to enable new UV space astronomy missions. Future UV missions will require improvements in detector sensitivity, which has the most leverage for cost-effective improvements in overall telescope/instrument sensitivity. We use new materials such as p-doped GaN, AlGaN, ZnMgO, SiC and diamond. We have currently obtained QE values > 40% at 185 nm with Cesiated GaN, and hope to demonstrate higher values in the future. By using controlled internal fields and nano-structuring of the surfaces, we plan to provide field emission assistance for photoelectrons while maintaining their energy distinction from dark noise electrons. We will transfer these methods from GaN to ZnMgO a new family of wide band-gap materials more compatible with microchannel plates. We also are exploring technical parameters such as doping profiles, internal and external field strengths, angle of incidence, field emission assistance, surface preparation, etc.

Paper Details

Date Published: 8 December 2003
PDF: 10 pages
Proc. SPIE 5164, UV/EUV and Visible Space Instrumentation for Astronomy II, (8 December 2003); doi: 10.1117/12.507528
Show Author Affiliations
Timothy J. Norton, Science Systems and Applications, Inc. (United States)
NASA Goddard Space Flight Ctr. (United States)
Bruce E. Woodgate, NASA Goddard Space Flight Ctr. (United States)
Joseph Stock, Swales Aerospace Inc. (United States)
George Hilton, Science Systems and Applications, Inc. (United States)
NASA Goddard Space Flight Ctr. (United States)
Melville P. Ulmer, Northwestern Univ. (United States)
Shahid Aslam, Raytheon ITSS (United States)
NASA Goddard Space Flight Ctr. (United States)
R. D. Vispute, Univ. of Maryland/College Park (United States)


Published in SPIE Proceedings Vol. 5164:
UV/EUV and Visible Space Instrumentation for Astronomy II
Oswald H. W. Siegmund, Editor(s)

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