Spin polarized photoemission from GaAs and its application to electron polarimetry
Johnson, Bruce Elliot
Dunning, F. Barry
Master of Science
Spin polarized electron sources based on photoemission from GaAs are widely used. Several new advanced photocathodes are under development. In the present work we have investigated the use of cathodes based on epitaxially grown p-type GaAs(11) layers, which are 1 nm thick, as a source of electrons of known polarization. For photon radiation at 87 nm, we observed an electron spin polarization of 4. ± 2.5 %. This is similar to earlier measurements made in other laboratories suggesting that indeed such epilayers can be used as a new derivative standard for calibrating electron polarimeters.