Results from Cs activated GaN photocathode development for MCP detector systems at NASA GSFC

Timothy Norton*, Bruce Woodgate, Joseph Stock, George Hilton, Melville P Ulmer, Shahid Aslam, R. D. Vispute

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

20 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)155-164
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5164
StatePublished - Dec 1 2003
EventUV/EUV and Visible Space Instrumentation for Astronomy II - San Diego, CA, United States
Duration: Aug 7 2003Aug 7 2003

Keywords

  • Detectors
  • Microchannel plates
  • Negative electron affinity
  • Photocathodes
  • Photon-counting

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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