| Spin-dependent effects in electron-atom collisions, including spin-orbit interaction, electron-electron exchange interaction and fine structure effect, are obscured in collisions between unpolarized electrons and atoms, but may be examined in detail when polarized electrons are employed. Integrated Stokes parameters measurement of light emitted by atoms excited by polarized electrons has been developed to be a powerful tool for direct studies of spin-dependent effects in electron-impact excitation process. Spin-polarized electron collision apparatus (SPECA), as the foundation of spin-dependent effects studies, is succeeded only by a few groups in the world for its great difficulty and complexity. However, the interest and prospect of the SPECA is increasing significantly for its importance and potential.The major objective in this dissertation is to design and construct a high performance SPECA, furthermore carry out measurement of integrated Stokes parameters for Helium atoms excited by polarized electrons based on the newly developed SPECA. It is a very difficult work with significant challenge and innovation for development of SPECA. During the development of SPECA, many key techniques have been developed, including the successfully design and construction of the stable and stringent ultrahigh vacuum system with high capability of differential pumping (the pressures in spin source chamber and collision chamber are 4×10-8 Pa and 1×10-5 Pa, respectively), the complicated magnetic field shielding system instead of Helmholtz coils (<10mG in spin source chamber and differential pumping chamber, <5mG in collision chamber), GaAs spin-polarized electron source with high precision of control and measurement of temperature, electron optics system for transmission of low energy electrons through long distance, and Stokes parameters analyzer. The new SPECA with high performance has been developed successfully in China firstly by our group after several years of...
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