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@INPROCEEDINGS{Schmidt:1031494,
      author       = {Schmidt, Norberto and Schwab, Alexander and Li, Jingjing
                      and Rücker, Ulrich and Voigt, Jörg and Lieutenant, Klaus
                      and Damián, José Ignacio Márquez and Granada, Rolando and
                      Dawidowski, Javier and Mauerhofer, Eric and Gutberlet,
                      Thomas and Zakalek, Paul},
      title        = {{C}omparison of experimental and simulated neutron cold
                      spectra for para- and ortho-hydrogen},
      reportid     = {FZJ-2024-05700},
      year         = {2024},
      abstract     = {The High Brilliance Neutron Source (HBS) [1] project aims
                      to develop a High-Current Accelerator-driven Neutron Source
                      (HiCANS) for neutron scattering, analytics, and imaging. It
                      will feature several cold neutron sources, including a
                      liquid para-hydrogen moderator. At the Forschungszentrum
                      Jülich, time-of-flight measurements were performed with the
                      prototype of such a cryogenic moderator for different ratios
                      between para- and ortho-hydrogen. In order to optimize the
                      design of future instruments that will use this cold neutron
                      source, an accurate description of the source
                      characteristics is necessary, which requires simulations of
                      the neutron transport to the detector for a comparison of
                      simulated and experimental data.This work focuses on the
                      comparison of various simulated spectra against experimental
                      ones for different para- and ortho-hydrogen ratios. Several
                      Monte Carlo codes, including MCNP, PHITS, McStas, VITESS,
                      and KDSource, and nuclear data from the ENDF/B-VII.1,
                      JENDL-4.0 and JENDL-5.0 libraries were utilized. The
                      simulations started with the comparison of the
                      proton-neutron yield spectra, continued with coupling the
                      event files before and after the modeling of the neutron
                      guide, and ended with the neutron time distribution at the
                      detector. A good agreement between simulations and
                      experiments was obtained, with a relative error below
                      $20\%.The$ results provide insights into the strengths and
                      limitations of each Monte Carlo code and nuclear data
                      library combination. Not only the observed discrepancies are
                      discussed, but also the potential sources of uncertainty are
                      identified. Also, the conclusions will help to improve the
                      accuracy and reliability of neutron cold moderator designs,
                      especially for projects that will deploy a para-hydrogen
                      cold source such as the HBS.[1] T. Brückel et al, 2022.
                      Technical Design Report High Brilliance Neutron Source.
                      Forschungszentrum Jülich.
                      https://doi.org/10.34734/FZJ-2023-03722},
      month         = {Sep},
      date          = {2024-09-16},
      organization  = {Deutsche Neutronstreutagung, RWTH
                       Aachen (Germany), 16 Sep 2024 - 18 Sep
                       2024},
      subtyp        = {Invited},
      cin          = {JCNS-2 / JCNS-HBS / JARA-FIT},
      cid          = {I:(DE-Juel1)JCNS-2-20110106 / I:(DE-Juel1)JCNS-HBS-20180709
                      / $I:(DE-82)080009_20140620$},
      pnm          = {632 - Materials – Quantum, Complex and Functional
                      Materials (POF4-632) / 6G4 - Jülich Centre for Neutron
                      Research (JCNS) (FZJ) (POF4-6G4)},
      pid          = {G:(DE-HGF)POF4-632 / G:(DE-HGF)POF4-6G4},
      typ          = {PUB:(DE-HGF)24},
      url          = {https://juser.fz-juelich.de/record/1031494},
}