Development of polarized electron source using GaAs-AlGaAs superlattice

A spin polarized electron beam is a very powerful tool to study the electroweak interaction by electron positron colliders at high energy. In linear colliders, for example, the JLC polarized electrons can be introduced to a interaction point without depolarization during acceleration, therefore a development of the polarized electron source is very important. The authors have measured a polarization of photoelectrons emitted from a GaAs-AlGaAs superlattice. The polarization of 52.5 + 0.3(stat.) + 5.0(sys.)% was obtained at a photon wavelength of 775 to 800nm. This polarization is interpreted that electrons excited from the heavy hole state only