Speaker
Description
Summary
Using the electron stretcher accelerator ELSA as an example, the method of Compton polarimetry will be explained. It is based on Compton backscattering of circularly polarized laser light off the longitudinally or transversely polarized revolving electrons. Two methods for detecting the backscattered photons will be presented: measurement of the integral asymmetry and measurement of the shift of the center of the photon intensity distribution when changing the helicity of the laser beam. Whereas the analyzing power of the first method is strongly sensitive on width and divergence of the electron beam, the second one is almost independent of the beam parameters. The requirements on the detector, depending on the envisaged measurement precision, will be discussed. A novel method for photon detection, using a counting silicon strip detector, will be presented. First results obtained at ELSA will be presented and compared with a possible employment at future storage rings.
