Optically pumped spin-exchange polarized-electron source

Authors

Munir Pirbhai, University of NebraskaFollow
J. Knepper, University of Nebraska-Lincoln
E. T. Litaker, University of Nebraska-LincolnFollow
D. Tupa, Los Alamos National Laboratory, Los Alamos, New MexicoFollow
Timothy J. Gay, University of Nebraska - LincolnFollow

Date of this Version

2013

Citation

PHYSICAL REVIEW A 88, 060701(R) (2013)

DOI: 10.1103/PhysRevA.88.060701

Comments

©2013 American Physical Society. Used by permission.

Abstract

We describe the operation of a prototype polarized-electron source. Rubidium vapor, contained in a cell, is optically pumped in the presence of a buffer gas. Unpolarized electrons from a tungsten filament are injected into the cell and extracted after undergoing spin exchange with the Rb atoms. We compare the performance of the source when different buffer gases are used. We measure a decrease in electron polarization as their injection energy increases, but find an unexpected regime at higher injection energies yielding increased electron polarization accompanied by a 40-fold increase in current, suggesting the production of slow secondary electrons in the target cell. With ethylene, we have measured electron currents of 4 μA simultaneously with electron polarizations of 24%. This work offers the promise of a simple, benchtop, “turnkey” source of polarized electrons.