Author: Montgomery, E.J.
Paper Title Page
THP204 Corrections to Quantum Efficiency Predictions for Low Work Function Electron Sources 2504
 
  • K. L. Jensen
    NRL, Washington, DC, USA
  • D.W. Feldman, E.J. Montgomery, P.G. O'Shea
    UMD, College Park, Maryland, USA
  • J.J. Petillo
    SAIC, Billerica, Massachusetts, USA
 
  Funding: Funding by the Joint Technology Office and the Office of Naval Research.
The Three-Step Model of Spicer, or the analogous Moments-based models, can be used to predict photoemission from metals and cesiated metals. In either, it is a convenient approximation to neglect electrons that have undergone scattering. Using Monte Carlo to follow scattered electrons, we assess the utility of the approximation particularly for low work function (cesiated) surfaces.
 
 
THP208 Development of Alkali-Based High Quantum Efficiency Semiconductors for Dispenser Photocathodes 2510
 
  • E.J. Montgomery, D.W. Feldman, S.A. Khan, P.G. O'Shea, P.Z. Pan, B.C. Riddick
    UMD, College Park, Maryland, USA
  • K. L. Jensen
    NRL, Washington, DC, USA
 
  Funding: This work is supported by the Office of Naval Research.
Photocathodes as electron beam sources can meet the stringent requirements of high performance FELs, but exhibit a lifetime-efficiency tradeoff. High quantum efficiency (QE) cathodes are typically semiconductors, well described by recently enhanced theory*. Cesium dispenser technology, proven to extend lifetime of tungsten cathodes**, can be extended to high QE via the development of semiconductor coatings which are suitable for rejuvenation. Rejuvenation occurs via controlled cesium diffusion through a sintered substrate to resupply the surface (as described by models of pore*** and surface**** diffusion). Compatible coatings must be thermally stable materials with a cesium-based surface layer. Following standard fabrication processes*****, we discuss alkali antimonides and alkali aurides as cesium dispenser photocathode coatings and analyze future prospects. We also describe improvements to experimental techniques.
*K.L. Jensen et al., (this conference)
**Moody et al., J. Appl. Phys. 102(10), 2010
***B.C. Riddick et al., (this conference)
****P.Z. Pan et al., (this conference)
*****S.A. Khan et al., (this conference)