Review of Spin Manipulator in EIC

To reduce systematic error, polarized beam collisions are arranged with various collision spin pattern (++, +-, -+,--). Because the same bunches collide for a given interaction point, periodically reversing the spin will reduce systematic errors for asymmetry measurements even further. To flip spin periodically during store, spin manipulation device such as spin flipper is needed. At polarized collider with spin tune at ½, the spin flip operation is more complicated than at low energies. A 9-manget spin flipper was introduced in Relativistic Heavy Ion Collider (RHIC). Over 97% spin flip efficiency has been demonstrated at injection and store energies. The same device can also measure spin tune non-destructively. A similar device can be used for Electron Ion Collider (EIC). This paper summarizes the RHIC spin manipulation results and perspective spin manipulation for EIC.