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2009
Journal Article
Titel
Linearly polarised photon beams at ELSA and measurement of the beam asymmetry in pi0 photoproduction omikron the proton
Abstract
At the electron accelerator ELSA a Iinearly polarised tagged photon beam is produced by coherent bremsstrahlung omikron a diamond crystal. Orientation and energy range of the linear polarisation can be deliberately chosen by accurate positioning of the crystal with a goniometer. The degree of polarisation is determined by the form of the scattered electron spectrum. Good agreement between experiment and expectations on the basis of the experimental conditions is obtained. Polarisation degrees of Rhogamma = 40% are typically achieved at half of the primary electron energy. The determination of Rhogamma is confirmed by measuring the beam asymmetry, Sigma, in pi0 photoproduction and by a comparison of the results to independent measurements using laser backscattering.
Author(s)
Bayadilov, D.E.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. Petersburg Nuclear Physics Institute, Gatchina, Russia
Crede, V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. Department of Physics, Florida State University, Tallahassee, FL, USA
Novinski, D.V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. Petersburg Nuclear Physics Institute, Gatchina, Russia
Pee, H. van
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. II. Physikalisches Institut, Universität Giessen, Germany
Sarantsev, A.V.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. Petersburg Nuclear Physics Institute, Gatchina, Russia
Thoma, U.
Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany u. II. Physikalisches Institut, Universität Giessen, Germany