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@PHDTHESIS{Genster:873774,
      author       = {Genster, Christoph},
      title        = {{S}oft- und {H}ardwareentwicklung für die
                      {F}lüssigszintillator-{D}etektoren der nächsten
                      {G}eneration {JUNO} und {OSIRISS}oftware and hardware
                      development for the next-generation liquid scintillator
                      detectors {JUNO} and {OSIRIS}},
      school       = {RWTH Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {FZJ-2020-00988, HBZ: HT020314384},
      pages        = {202 p},
      year         = {2019},
      note         = {Dissertation, RWTH Aachen, 2019},
      abstract     = {Large liquid scintillator~(LS) detectors are acknowledged
                      instruments in the field of neutrino physics. Based on
                      various successful experiments, reporting the currently best
                      limits on several parameters of neutrino flavor
                      oscillations, a new generation of detectors with several
                      tens of kilotons of LS are under consideration. The Jiangmen
                      Underground Neutrino Observatory~(JUNO) is a 20 kiloton LS
                      detector, that is fully funded and under construction in
                      China. Its main goal is the determination of the neutrino
                      mass ordering~(MO) through a precision measurement of the
                      reactor electron anti-neutrino spectrum. The first part of
                      this thesis discusses the underlying theory of neutrino
                      flavor oscillations, the JUNO detector design and how
                      neutrinos of various sources can be detected with this
                      instrument. The focus is laid on a correlated background for
                      the inverse beta decay~(IBD) measurement of reactor
                      anti-neutrinos, which stems from cosmic muons. When they
                      traverse the detector, the muons can create unstable
                      radioisotopes, which decay after a short time in a (beta +
                      n) channel. In order to identify and reject this background,
                      it is paramount to know the track of the muon precisely. For
                      this purpose, a novel muon reconstruction algorithm is
                      developed and tested in this work. It is based on the
                      geometric model of the intersection of the first-light front
                      with the PMT array. The track parameters are optimized in a
                      likelihood fit based on probability density functions
                      produced with a detailed detector simulation. In addition, a
                      simulation of the full readout electronics is performed to
                      yield the best estimate of the performance on real data.
                      Excluding the edge of the CD, the muon track's distance from
                      the detector center DeltaD can be determined with an
                      uncertainty of 5 cm and its direction with 0.3°. The impact
                      on the detector's exposure by a muon veto based on this
                      reconstruction was also studied. Compared to a perfect
                      knowledge of each muon track, the developed method only
                      creates an additional 4 $\%$ of loss in exposure. In the
                      second part, a pre-detector for JUNO is investigated. OSIRIS
                      is a standalone, 20 ton LS detector, that will be used to
                      monitor the radiopurity of the cleaned LS before it is
                      filled into JUNO.In the scope of this work, a detailed
                      detector simulation based on C++11 and Geant4 is developed.
                      It is then used to determine the sensitivity of the detector
                      to its main physics goal: the identification of Bi-Po
                      coincidences from the decay chains of U-238 and Th-232 in
                      the LS. Furthermore, a calibration campaign for OSIRIS is
                      studied. Under consideration of the available hardware, the
                      decision is made to utilize an automated calibration
                      unit~(ACU) from the Daya Bay collaboration. The energy range
                      of 0.5 - 3 MeV will be calibrated by exposing the detector
                      simultaneously to Cs-137, Zn-65, and Co-60 in a single
                      capsule. With different vertical positions on a fixed radial
                      distance r = 120 cm from the detector's center, its
                      non-uniformity can be properly sampled. Timing calibration
                      of the PMTs with an accuracy of~0.1 ns is realized with a
                      430 nm LED, that can be deployed along the same vertical
                      axis.},
      cin          = {IKP-2},
      cid          = {I:(DE-Juel1)IKP-2-20111104},
      pnm          = {612 - Cosmic Matter in the Laboratory (POF3-612)},
      pid          = {G:(DE-HGF)POF3-612},
      typ          = {PUB:(DE-HGF)29 / PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2019-11430},
      url          = {https://juser.fz-juelich.de/record/873774},
}