High-Brightness Photocathodes through Ultrathin Surface Layers on Metals
Abstract
We report how ultrathin MgO films on Ag(001) surfaces can be used to control the emittance properties of photocathodes. In addition to substantially reducing the work function of the metal surface, the MgO layers also favorably influence the shape of the surface bands resulting in the generation of high-brightness electron beams. As the number of MgO surface layers varies from 0 to 3, the emitted electron beam becomes gradually brighter, reducing its transverse emittance to 0.06mmmrad. We suggest the use of such photocathodes for the development of free-electron x-ray lasers and energy-recovery linac x-ray sources.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2010
- DOI:
- 10.1103/PhysRevLett.104.046801
- Bibcode:
- 2010PhRvL.104d6801N
- Keywords:
-
- 73.20.At;
- 73.21.Ac;
- 73.21.Fg;
- Surface states band structure electron density of states;
- Multilayers;
- Quantum wells