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@MASTERSTHESIS{ElKordy:349916,
      author       = {El-Kordy, Tarek Ahmed},
      title        = {{S}torage {C}ell {T}ests for the {P}olarized {T}arget at
                      {LHC}b/{CERN}},
      school       = {FH Aachen},
      type         = {Masterarbeit},
      reportid     = {GSI-2024-00516},
      pages        = {90p},
      year         = {2023},
      note         = {Masterarbeit, FH Aachen, 2023},
      abstract     = {The gas injection system, referred to as the System for
                      Measuring Overlap With Gas(SMOG2), used in the Large Hadron
                      Collider beauty (LHCb) experiment at CERN,employs storage
                      cells to provide gas targets for collision experiments. In
                      the next stageof development, the LHCSpin project aims to
                      establish a polarized atomic hydrogen gastarget through the
                      utilization of an amorphous carbon-coated storage cell.At
                      the Nuclear Physics Institute of the Jülich research
                      center, an atomic beam sourcecapable of generating a
                      polarized atomic hydrogen beam was available, along with
                      aLamb-shift polarimeter capable of measuring the nuclear
                      polarization of hydrogen atomsand molecules. These resources
                      facilitated an in-depth exploration of the propertiesof such
                      a storage cell, with a specific focus on assessing the
                      recombination rate ofpolarized atoms and the polarization
                      preservation on carbon surfaces. Additionally, anovel beam
                      chopper design was introduced to investigate the impact of
                      the Lyman-αradiation induced desorption recombination
                      process.Results of mass spectrometry measurements, conducted
                      using a Wien filter in combinationwith a Faraday cup,
                      confirmed the absence of a dominant superficial water layer
                      andrevealed the beam chopper’s limitations in effectively
                      reducing atomic beam and photonintensity. Utilizing
                      transition units alongside a spin filter, polarization
                      measurementsfor atomic hydrogen showed a recombination rate
                      ranging from $95.8\%$ to $100\%$ and amaximum vector
                      polarization of −0.606 ± 0.002. In the case of molecular
                      hydrogen,measurements indicated a maximum polarization of
                      −0.54±0.01. The observed characteristicsalign with fit
                      parameters derived from a mathematical model describing the
                      lossof polarization due to surface interactions.These
                      findings emphasize the feasibility of employing
                      carbon-coated storage cells aswater-repellent, polarized
                      molecular gas targets in accelerator experiments.
                      Leveragingthe high-energy ion beam delivered by the Large
                      Hadron Collider creates possibilitiesfor conducting spin
                      physics experiments that were previously beyond reach.},
      cin          = {FFN},
      cid          = {I:(DE-Ds200)FFN-20210302OR452},
      pnm          = {612 - Cosmic Matter in the Laboratory (POF4-612)},
      pid          = {G:(DE-HGF)POF4-612},
      experiment   = {$EXP:(DE-Ds200)External_experiment-20200803$},
      typ          = {PUB:(DE-HGF)19},
      url          = {https://repository.gsi.de/record/349916},
}