[en] We are building a new type of Compton Polarimeter for a few GeV electron beam. To increase the efficiency of the polarimeter, the electron-photon interaction occurs inside an optical used to amplify the IR laser beam intensity. We aim at a photon beam power of 1000 W in the cavity, using a 300 mW. We describe the general design of this polarimeter and we discuss its expected performances. (author)

[en] Very large aperture quadrupole magnets have been recently considered as possible spectrometers on high energy colliders. The interesting characteristics are zero field on beam axis, low fields at small angles, transverse field at large angles. Dimension range is 1 m to 5 m for clear bore and 2 m to 8 m for length; typical maximum field is 2.5 T. Superconducting magnets with cosine 2 θ structure, coils with one or two layers and iron yoke have been modeled. Use of two types of conductors have been investigated: Rutherford cable and aluminium stabilized composite. The paper describes the optimization procedure and gives diagrams of feasibility. Two alternative structures are mentioned: superferric and active shield magnets

[en] A new kind of compton polarimeter using a resonant Fabry-Perot cavity as a power buildup for the photon beam is proposed. A prototype of such a cavity is described, along with the results obtained in terms of source to be used in a compton scattering polarimeter. (orig.)

[en] This report describes the design of the Compton polarimeter for the Cebaf electron beam in End Station A. The method of Compton polarimeter is first introduced. It is shown that at CEBAF beam intensities, the use of standard visible LASER light gives too low counting rates. An amplification scheme of the LASER beam based on a high finesse optical cavity is proposed. Expected luminosities with and without such a cavity are given. The polarimeter setup, including a 4 dipole magnet chicane, a photon and an electron detector, is detailed. The various sources of systematic error on the electron beam polarization measurement are discussed. (author)