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A Simplified Gaas Polarized Electron Source, H. M. Al-Khateeb, B. G. Birdsey, T. C. Bowen, A. S. Green, M. E. Johnston, Timothy J. Gay
A Simplified Gaas Polarized Electron Source, H. M. Al-Khateeb, B. G. Birdsey, T. C. Bowen, A. S. Green, M. E. Johnston, Timothy J. Gay
Timothy J. Gay Publications
We report operational and construction details of a simplified GaAs polarized electron source. It is contained in a modified 4.63 in. Conflat four-way cross, and uses a single 56 ℓ /s turbomolecular pump. The design incorporates multiple cesiators to extend source lifetime, a new spring-clamp GaAs crystal mounting design to provide uniform crystal heating, and a very simple tubular 90° electrostatic deflector. We also discuss matters related to preparing, heat cleaning, and activating the GaAs crystal.
Near-Threshold Measurement Of Integrated Stokes Parameters For Kr Excited By Polarized Electrons, B. G. Birdsey, H. M. Al-Khateeb, M. E. Johnston, T. C. Bowen, Timothy J. Gay, V. Zeman, K. Bartschat
Near-Threshold Measurement Of Integrated Stokes Parameters For Kr Excited By Polarized Electrons, B. G. Birdsey, H. M. Al-Khateeb, M. E. Johnston, T. C. Bowen, Timothy J. Gay, V. Zeman, K. Bartschat
Timothy J. Gay Publications
We have made high-accuracy measurements of the integrated Stokes parameters for resonance fluorescence from polarized electron-impact excitation of the 4p55p[5/2] 3D3 and 4p55p [5/2] 3D2 states of Kr. We report measurements in the region within 0.6 eV of threshold, which is below the first cascade threshold. We also present theoretical calculations of these Stokes parameters using a recently developed relativistic Breit-Pauli Rmatrix code. In well LS-coupled systems, nonzero values of the integrated Stokes parameter P2 signal relativistic effects (like continuum spin-orbit coupling, i.e., Mott scattering). …
Optically Pumped Electron Spin Filter, Herman Batelaan, A. S. Green, B. A. Hitt, Timothy J. Gay
Optically Pumped Electron Spin Filter, Herman Batelaan, A. S. Green, B. A. Hitt, Timothy J. Gay
Timothy J. Gay Publications
This paper reports the first experimental demonstration of an optically pumped electron spin filter. Unpolarized electrons produced in a cold-cathode discharge drift through a mixture of spin-polarized Rb and a nitrogen or helium buffer gas. Through spin-exchange collisions with the Rb, the drifting electrons become polarized along the optical pumping axis. We study the role of the buffer gas in both the optical pumping and the spin transfer to the free electrons. This spin filter produces electron beams with currents and polarizations comparable to first-generation GaAs polarized electron sources.