Precision, absolute proton polarization measurements at 200 MeV beam energy

A new polarimeter for absolute proton beam polarization measurements at 200 MeV to accuracy better than ±0.5% has been developed as a part of the RHIC polarized source upgrade. The polarimeter is based on the elastic proton-carbon scattering at 16.2° angle, where the analyzing power is close to 100% and was measured with high accuracy. The elastically and in-elastically scattered protons are clearly identified by the difference in the propagation through variable copper absorber and energy deposition of the protons in the detectors. The elastic scattering polarimeter was used for calibration of a high rate inclusive 12° polarimer for the on-line polarization tuning and monitoring. This technique can be used for accurate polarization measurements in energy range of at least 160-250 MeV.