Polarized antiprotons allow unique access to a number of fundamental physics observables.
One example is the transversity distribution which is the last missing piece to complete
the knowledge of the nucleon partonic structure at leading twist in the QCD-based parton
model. The transversity is directly measurable via Drell-Yan production in double polarized
antiproton-proton collisions. This and a multitude of other findings, which are accessible
via ppbar scattering experiments, led the Polarized Antiproton eXperiments (PAX) collaboration
to propose such investigations at the High Energy Storage Ring (HESR) of the Facility for
Antiproton and Ion Research (FAIR).
Already the production of intense polarized antiproton beams is still an unsolved problem.
The PAX anticipated time plan to experiments at HESR mainly consists of three phases.
PAX@COSY, as first step, is aiming for an optimization of the polarization build-up in
proton beams at the Cooler Synchrotron COSY Jülich. The spin-filtering method, where
the originally unpolarized beam becomes polarized due to the spin-dependent part of the
hadronic interaction with a Polarized Internal Target (PIT), will be applied. The feasibility of
this method was shown to work for protons by the Filter Experiment (FILTEX) at the Test
Storage Ring (TSR) in Heidelberg. PAX@CERN will determine the spin-dependent cross
sections in ppbar scattering at beam energies of 50 - 450 MeV using the antiproton beam of
the Antiproton Decelerator (AD) at CERN. PAX@FAIR constitutes the third phase where the
antiproton beam will be polarized in a dedicated Antiproton Polarizer Ring (APR) at the
HESR, converted into a double-polarized proton-antiproton collider, in order to study the
transverse spin structure of nucleons.
The present thesis discusses the preparations for the spin-filtering experiments at COSY. This
includes the successful installation and commissioning of the experimental equipment such
as a low-β section, a dedicated pumping system, an Atomic Beam Source (ABS), a Breit-
Rabi Polarimeter (BRP), and a target chamber with an openable storage cell. In addition,
the accomplished investigations of the beam lifetime dependencies, resulting in significantly
improved beam lifetimes, and relevant machine parameters, e.g., the machine acceptance, are
described. The results are utilized to calculate the expected polarization build-up in a cooled
and stored proton beam with a kinetic energy of 49.3MeV using a target with an areal density
of 5*10¹³ atoms/cm². Simulations of the determination of the beam polarization using elastic
proton-deuteron scattering and a polarimeter, that consists of silicon micro-strip detectors,
allows one to estimate the achievable precision of the measurement of the spin-dependent
total hadronic cross section. The presented results constitute the basis of a beam time request
for transverse spin-filtering to the COSY Program Advisory Committee (PAC), which was
approved in spring 2011
