4π-continuous mode polarized solid state target

For high quality measurements of polarization variables at CB-ELSA the Polarized Target Group in Bonn focusses much of its efforts on the improvement of the instrumentation and hardware. Currently one of the main tasks is the competition of a 4π-continuous mode target which could be used to maintain higher mean polarization values at lower temperatures. The new cryostat uses specially designed pre-cooling elements as well a unique superconducting inverse notched coil for polarization. Due to this development the need for the cumbersome alternation of polarization and data-taking is removed and makes an external polarizing magnet unnecessary. In addition the data-taking period in cold operation is increased. It is designed to provide a transversal and a longitudinal polarization if necessary.