Latest on Polarization in Electron Storage Rings

To sum up, the over-all situation is a healthy one: (1) The linear theory of beam polarization and depolarization is substantially understood. Thanks to the transparency conditions proper design of spin manipulators (rotators, Siberian snakes, spin chromaticity correctors, etc.) becomes possible and corrections for rings with imperfections have been reduced to a problem of finding the most effective correction knobs. (2) Experts are working on the nonlinear theories. Their results so far are encouraging. Nonlinear depolarization effects associated with large energy spread seem to be a problem for LEPTbut there is no lack of clever schemes to choose from for defeating these effects. The heam-beam depolarization is only marginally harmful and there are again preliminary ideas of how to fight it. (3) Polarization monitoring seems to require only a reasonable extension of the present technology.