Lehrach, A. (Corresponding author)FZJ*

1998
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Abstract: Acceleration of the Polarized Proton Beam in the Cooler Synchrotron COSY The COoler SYnchrotron COSY at the Forschungszentrum Jülich accelerates protons up to a momentum of 3.4 GeV je. A concept has been developed and realized to accelerate a vertically polarized proton beam in COSY. In addition, different Siberian snake schemes for COSY were investigated. The acceleration of a polarized beam in a circular accelerator is a delicate topic. During the acceleration strong depolarizing resonances, called imperfection or intrinsic resonances, are crossed. The existing magnet system of COSY is sufficient to overcome imperfection resonances. Correction dipoles and the solenoids of the electron cooler acting as a partial snake were successfully used to conserve the polarization by exciting adiabatic spin flips. Both methods are available for all five imperfection resonances in the momentum range of COSY. With the standard optics of COSY five intrinsic resonances are excited. Calculations predict the possibility to suppress three of these resonances by changing the optics during acceleration. This method enables the acceleration of the polarized beam up to 2 GeV je. For the remaining intrinsic resonances a tune jump is necessary. A magnet system consisting of two ir on free pulsed quadrupoles was developed and successfully used. Polarization measurements during acceleration confirm that the developed concept allows the acceleration of a vertically polarized proton beam up to the maximum momentum of COSY. The installation of a Siberian snake could also provide a longitudinally polarized beam.

1. Institut für Kernphysik (IKP)