Author/Authors :
Falletto، نويسنده , , N and Authier، نويسنده , , M and Baylac، نويسنده , , M and Boyer، نويسنده , , M and Bugeon، نويسنده , , F and Burtin، نويسنده , , E and Cavata، نويسنده , , C and Colombel، نويسنده , , N and Congretel، نويسنده , , G and Coquillard، نويسنده , , R and Coulloux، نويسنده , , G and Couzy، نويسنده , , B and Deck، نويسنده , , P and Delbart، نويسنده , , A and Desforges، نويسنده , , D and Donati، نويسنده , , A and Duboué، نويسنده , , B and Esc، نويسنده ,
Abstract :
We built and commissioned a new type of Compton polarimeter to measure the electron beam polarization at the Thomas Jefferson National Accelerator Facility (Virginia, USA). The heart of this polarimeter is a high-finesse monolithic Fabry–Pérot cavity. Its purpose is to amplify a primary 300 mW laser beam in order to improve the signal to noise ratio of the polarimeter. It is the first time that a high-finesse Fabry–Pérot cavity is enclosed in the vacuum of a particle accelerator to monitor the beam polarization by Compton polarimetry. The measured finesse and amplification gain of the cavity are F=26 000 and G=7300. The electron beam crosses this high-power photon source at an angle of 23 mrad in the middle of the cavity where the photon beam power density is estimated to be 0.85 MW/cm2. We have used this facility during the HAPPEX experiment (April–July 1999) and we give a preliminary measurement of Compton scattering asymmetry.
