Berlin 2005 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 22: Postersitzung

HK 22.93: Poster

Montag, 7. März 2005, 16:30–18:00, TU MA141

A new bremsstrahlung tagging system for the CBELSA experiment* — •Kathrin Fornet-Ponse, Susanne Kammer, and Andre Süle — Physikalisches Institut Universität Bonn

For future double polarisation experiments at CBELSA with real photon beams and polarised proton and neutron targets, a new photon tagging system has been designed. It enables accurate flux determination and the control and measurement of both linear and circular beam polarisation. The tagger consists of a dipol magnet for momentum selection of the decelerated electrons. Using standard focal plane hodoscopes a photon energy resolution of 0.2-2.2% over the tagging range of 4-82% of the electron beam energy is achieved. The photon flux is determined from geometrically overlapping scintillator channels. Control of the linear polarisation of the photon beam is provided by adequate orientation of a diamond radiator using a commercial goniometer. The measurement of the circular photon beam polarisation requires Møller polarimetry of the longitudinally polarised electron beam. This shall be realised by using polarised ferromagnetic radiator foils and the coincident measurement of the symmetric Møller pairs in a dedicated focal plane detection system.

* supported by DFG (SFB/TR 16).