Improving light yield in a LAr veto for neutrinoless double beta decay searches

ORAL

Abstract

The Large Enriched Germanium Experiment for Neutrinoless double beta Decay (LEGEND) is an upcoming experiment searching for neutrinoless double beta decay. This process has a predicted half-life of at least $10^{27}$ yrs in 76Ge, therefore reducing radioactive backgrounds that could mimic the expected signals is the largest challenge facing the experiment. A method that has been shown to work is to veto external backgrounds by surrounding the Ge detectors with a volume of liquid argon (LAr) scintillator. Our work is focused on improving the efficiency of the LAr veto by studying methods to maximize the scintillation light yield. With a LAr test stand we detect the scintillation using PMTs and measure the light yield by counting photons and characterizing the pulse shape. By measuring the lifetime of the triplet state in LAr we have demonstrated that the removal of impurities in argon greatly improves light yield. We plan to dope the LAr with ppm-levels of xenon, which has also been shown to improve light yield in small-scale detectors. Additionally, we are performing optical simulations with Geant4 to optimize the geometry of the Ge detectors and the light collection system, which will be used to inform the best design for the LEGEND experiment.

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Authors

  • Ryan Gibbons

    The University of New Mexico

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago

  • John Spence

    Brigham Young University, Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, Department of Scientific Research, The Metropolitan Museum of Art, New York, NY 10028, Century Darkroom, Toronto, ON M4M 2S1, Canada, Colorado State University, University of Waterloo, Southern Connecticut State University, Clemson University, Oak Ridge National Laboratory, University of Bordeaux, BYU REU Program, New Mexico State University, Arizona State University, Biodesign Institute, Center for Applied Structural Discovery, University of Utah, University of Hawaii, Johns Hopkins University, Embry-Riddle Aeronautical University, Arizona State University, Utah State University, Department of Physics, United States Air Force Academy, Department of Chemistry, Case Western Reserve University, Air Force Research Laboratory, Wright-Patterson Air Force Base, United States Air Force Academy, Lousiana State University, Brigham Young University - Provo, The University of New Mexico, Department of Physics and Astronomy, Brigham Young University, SLAC National Accelerator Laboratory, Department of Chemistry, Brigham Young University, Department of Materials, Devices, and Energy Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA, Department of Physics, New Mexico State University, Las Cruces, New Mexico 88003, USA, Center for Memory and Recording research, UCSD, Advanced Photon Source, Argonne National Laboratory, University of New Mexico, Los Alamos National Laboratory, University of Chicago