Abstract
We developed a Mott analyzer of the spherical accelerator type, to measure the spin polarization of electrons extracted from a ferro-magnetic tip or a GaAs sample. This analyzer was designed for a low-acceleration voltage (40 kV). Inelastic scattered electrons are retarded by spherical electrodes. This paper reports the spin polarization of electrons extracted from negative electron affinity (NEA)-GaAs. It was found that this type of Mott analyzer involves a few problems to be solved.