12-13 February 2014
Europe/Berlin timezone

Challenges for Polarimetry at the ILC

12 Feb 2014, 15:30


Institut für Kernphysik; Johannes Gutenberg-Universität Mainz; Johann-Joachim-Becher-Weg 45; D 55128 Mainz


Moritz Beckmann (DESY)


At the planned International Linear Collider (ILC), the longitudinal beam polarization needs to be determined with an unprecedented precision. For that purpose, the beam delivery systems (BDS) are equipped with two laser Compton polarimeters each, which are foreseen to achieve a systematic uncertainty of 0.25 %. The polarimeters are located 1.6 km upstream and 150 m downstream of the e^+e^- interaction point (IP). The average luminosity-weighted longitudinal polarization, which is the decisive quantity for the experiments, has to be determined from these measurements with the best possible precision. Therefore, a detailed understanding of the spin transport in the BDS is mandatory to estimate how precise the longitudinal polarization at the IP is known from the polarimeter measurements. The envisaged precision for the propagation of the measurement value is 0.1 %. The spin transport in the BDS has been simulated, including the simulation of the beam-beam collisions at the IP. This talk discusses the results of this study with focus on the collision effects and the spin transport after the collision.

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