Berlin 2005 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 29: Instrumentation und Anwendungen
HK 29.1: Vortrag
Dienstag, 8. März 2005, 14:00–14:15, TU MA042
Beam-Induced Depolarisation in the HERMES Transversely Polarised Hydrogen Target — •Davide Reggiani, Erhard Steffens, and Phil Tait — Physikalisches Institut, Universität Erlangen-Nürnberg, 91058 Erlangen
The HERMES polarised hydrogen target is situated in the HERA electron storage ring in Hamburg. For the transverse spin program at HERMES, the magnetic holding field of the target is perpendicular to the HERA positron beam. An unwanted consequence is that the beam-induced resonance between hydrogen hyperfine states with Δ mF=0, which was previously forbidden, can occur. The shape and spacing of these resonances will be shown. In order to prevent these resonances from reducing the nuclear polarization in the target cell, a pair of correction coils have been added to improve the field homogeneity. The change of the resonance shape and the increase of the target polarization obtained by using these coils will be presented along with an overview of the overall target performance.