Polarimetry - from basics to precision

Abstract

In all experiments involving polarized beams or/and targets, the determination of the degree of polarization by asymmetry measurements is of prime importance. Over the years, so-called analyzing powers were extracted, e.g., for various reactions for well-defined beam/target polarizations as a function of the reaction energy. Reciprocally, the polarization can be deduced precisely from measured asymmetries if the analyzing power is known. In practice, the task may become complicated by the required unambiguous identification of the reaction channel. In cases where the statistics are limited, such as, e.g., in the planned EDM (Electric Dipole Moment)-search for charged particles in storage rings, polarimetry becomes a real challenge. In this overview, different aspects of possible polarimetry concepts, the efficient reaction selection, and the quasi non-invasive scattering targets will be discussed. Also, the recent progress achieved by the JEDI collaboration using polarized deuteron beams of COSY-J\"ulich will be presented.