Institut de recherche sur les lois fondamentales de l'Univers

Direction de la recherche fondamentale

Résumé du preprint DAPNIA-00-04

DAPNIA-00-04
Compton Scattering off polarized electrons with a High Finesse Fabry-Pérot Cavity at JLab
N.Falletto, M.Authier, G.Bardin, M.Baylac, M.Boyer, F.Bugeon, E.Burtin, C.Cavata, N.Colombel, G.Congretel, R.Coquillard, G.Coulloux, B.Couzy, P.Deck, A.Delbart, D.Desforges, A.Donati, B.Duboue, S.Escoffier, F.Farci, B.Frois, P.Girardot, J.Guillotau, C.Henriot, J.Jardillier, C.Jeanney, M.Juillard, J-P.Jorda, P.Legou, D.Lhuillier, Y.Lussignol, Ph.Mangeot, X.Martin, F.Marie, J.Martino, M.Maurier, B.Mazeau, J.F.Millot, F.Molinie, J-P.Mols, J-P.Mouly, M.Mur, D.Neyret, T.Pedrol, S.Platchkov, G.Pontet, T.Pussieux, Y.Queinec , Ph.Rebourgeard, J.C.Sellier, G.Tarte, C.Veyssiere, A.Zakarian (DAPNIA CEA Saclay, France) P.Bertin, A.Cosquer (LPC/IN2P3 Clermont Ferrand, France) J. P.Chen, J.Mitchell (Thomas Jefferson National Accelerator Facility, Newport News, VA, USA) J-M. Mackowski, L. Pinard (IPNL/IN2P3 Universite Claude Bernard Lyon I, Villeurbanne, France)
Abstract : ======= We built and commissioned a new type of Compton polarimeter to measure the electron beam polarization at the Thomas Jeferson National Accelerator Facility (Virginia, USA). The heart of this polarimeter is a High Finesse monolithic Fabry- P�rot 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-P�rot 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 = 26000 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/cm� . We have used this facility during the HAPPEX experiment (April-July 1999) and we give a preliminary measurement of Compton scattering asymmetry.

DAPNIA-00-04

Compton Scattering off polarized electrons with a High Finesse Fabry-Pérot Cavity at JLab

N.Falletto, M.Authier, G.Bardin, M.Baylac, M.Boyer, F.Bugeon, E.Burtin, C.Cavata, N.Colombel, G.Congretel, R.Coquillard, G.Coulloux, B.Couzy, P.Deck, A.Delbart, D.Desforges, A.Donati, B.Duboue, S.Escoffier, F.Farci, B.Frois, P.Girardot, J.Guillotau, C.Henriot, J.Jardillier, C.Jeanney, M.Juillard, J-P.Jorda, P.Legou, D.Lhuillier, Y.Lussignol, Ph.Mangeot, X.Martin, F.Marie, J.Martino, M.Maurier, B.Mazeau, J.F.Millot, F.Molinie, J-P.Mols, J-P.Mouly, M.Mur, D.Neyret, T.Pedrol, S.Platchkov, G.Pontet, T.Pussieux, Y.Queinec , Ph.Rebourgeard, J.C.Sellier, G.Tarte, C.Veyssiere, A.Zakarian (DAPNIA CEA Saclay, France) P.Bertin, A.Cosquer (LPC/IN2P3 Clermont Ferrand, France) J. P.Chen, J.Mitchell (Thomas Jefferson National Accelerator Facility, Newport News, VA, USA) J-M. Mackowski, L. Pinard (IPNL/IN2P3 Universite Claude Bernard Lyon I, Villeurbanne, France)

Abstract :
=======

We built and commissioned a new type of Compton polarimeter to measure the
electron beam polarization at the Thomas Jeferson National Accelerator Facility
(Virginia, USA). The heart of this polarimeter is a High Finesse monolithic Fabry-
P�rot 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-P�rot 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 = 26000 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/cm� .
We have used this facility during the HAPPEX experiment (April-July 1999) and
we give a preliminary measurement of Compton scattering asymmetry.