IPAC'24 - 15th International Particle Accelerator Conference

Chemical robustness enhancement of negative electron affinity photocathodes through cesium-iodide deposition

MOPR82

20 May 2024, 16:00

2h

Rock 'n Roll (MCC Exhibit Hall A)

Poster Presentation MC3.T02 Electron Sources Monday Poster Session

Speaker

Samuel Levenson (Cornell University (CLASSE))

Description

Photocathodes at Negative Electron Affinity (NEA), like GaAs and GaN, allow for efficient production of spin-polarized electrons. When activated to NEA with cesium and an oxidant, they are characterized by an extreme sensitivity to chemical poisoning, resulting in a short operational lifetime. In this work, we demonstrate that deposition of a cesium iodide (CsI) layer can be used to enhance the dark lifetime of both GaN and GaAs photocathodes activated with cesium. The mechanism behind this improvement is investigated using X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM) techniques.

Funding Agency

This work is supported by the U.S. National Science Foundation under Award No. PHY-1549132, the Center for Bright Beams, NSF-1734189 and U.S. Department of Energy grants DE-SC0021002 and DE-SC0021425.