Quantum effects for electrons in a storage ring are studied in a co-moving, accelerated frame. The polarization effect due to spin flip synchrotron radiation is examined by treating the electron as a simple quantum mechanical two-level system coupled to the orbital motion and to the radiation field. The excitations of the spin system are related to the Unruh effect, i.e. the effect that an accelerated radiation detector is thermally excited by vacuum fluctuations. The importance of orbital fluctuations is pointed out and the vertical fluctuations are examined.