Polarimetry for the polarized deuterium target at ANKE/COSY

Abstract

The understanding of the NN interaction is fundamental to the whole of nuclear and hadronic physics. The scattering amplitudes for the complete description of NN interactions can be reconstructed from phase-shift analyses (PSA), which require measurements with polarized beam and polarized target. Very little is known about the np system above 800 MeV nucleon energy. The ANKE collaboration at COSY-Julich has proposed to extract np scattering amplitudes using deuterons as a source of quasi-free neutrons. The first part of the program with a polarized deuteron beam and a hydrogen target allowed successful determination of np amplitudes up to 1.15 GeV nucleon energy. Use of a polarized deuterium target and a proton beam will allow to increase np studies up to 2.8 GeV, the highest energy available at COSY. In order to compensate the low density of the atomic beam source (ABS), polarized deuterium gas will be injected into a storage cell, placed along the COSY beam direction. Commissioning of the polarized deuterium target at ANKE was carried out in June 2012. Nuclear reactions with large and well-known cross sections and analyzing powers were selected to measure the target vector and tensor polarizations (Qyand Qyy). © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.