Operation of Cs-Sb-O activated GaAs in a high voltage DC electron gun at high average current

TL;DR

This paper demonstrates that Cs-Sb-O activated GaAs photocathodes can operate at high voltages to produce high current electron beams with significantly improved lifetime, especially at 780 nm wavelength.

Contribution

It introduces a new Cs-Sb-O activation method for GaAs photocathodes that enhances lifetime in high voltage, high current applications.

Findings

45% lifetime increase at 780 nm with Cs-Sb-O activation

Spectral dependence affects lifetime improvement

Successful operation at high voltage for high current output

Abstract

Negative Electron Affinity (NEA) activated GaAs photocathodes are the most popular option for generating a high current (> 1 mA) spin-polarized electron beam. Despite its popularity, a short operational lifetime is the main drawback of this material. Recent works have shown that the lifetime can be improved by using a robust Cs-Sb-O NEA layer with minimal adverse effects. In this work, we operate GaAs photocathodes with this new activation method in a high voltage environment to extract a high current. We observed spectral dependence on the lifetime improvement. In particular, we saw a 45% increase in the lifetime at 780 nm for Cs-Sb-O activated GaAs compared to Cs-O activated GaAs.