Speaker
Description
GaAs photocathodes operated in a negative electron affinity (NEA) state typically achieve 35%-40% photoemitted electron spin polarization (ESP). However, when operated in a slight positive electron affinity (PEA) state, the barrier for electrons to escape into vacuum can cause upwards of 50% ESP electron beams to be photoemitted. In this proceeding, we explore the mechanisms and limitations of this effect. This is done experimentally with ESP measurements performed in a retarding-field Mott polarimeter on GaAs photocathodes with varying electron affinities, and theoretical modeling of material properties through Monte Carlo simulations.
Funding Agency
This work is supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams and by the U.S. Department of Energy under Award DE-SC0023517.
| Region represented | America |
|---|---|
| Paper preparation format | LaTeX |
