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Arnquist IJ, Avignone FT, Barabash AS, Barton CJ, Bertrand FE, Blalock E, Bos B, Busch M, Buuck M, Caldwell TS, Chan YD, Christofferson CD, Chu PH, Clark ML, Cuesta C, Detwiler JA, Drobizhev A, Edwards TR, Edwins DW, Edzards F, Efremenko Y, Elliott SR, Gilliss T, Giovanetti GK, Green MP, Gruszko J, Guinn IS, Guiseppe VE, Haufe CR, Hegedus RJ, Henning R, Aguilar DH, Hoppe EW, Hostiuc A, Kim I, Kouzes RT, Lopez AM, López-Castaño JM, Martin EL, Martin RD, Massarczyk R, Meijer SJ, Mertens S, Myslik J, Oli TK, Othman G, Pettus W, Poon AWP, Radford DC, Rager J, Reine AL, Rielage K, Ruof NW, Saykı B, Schönert S, Stortini MJ, Tedeschi D, Varner RL, Vasilyev S, Wilkerson JF, Willers M, Wiseman C, Xu W, Yu CH, Zhu BX. α -event characterization and rejection in point-contact HPGe detectors. Eur Phys J C Part Fields 2022; 82:226. [PMID: 35310515 PMCID: PMC8921096 DOI: 10.1140/epjc/s10052-022-10161-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector's response to α particles incident on the sensitive passivated and p + surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the Majorana Demonstrator experiment, a search for neutrinoless double-beta decay ( 0 ν β β ) in 76 Ge. α decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of α identification, reliably identifying α background events on the passivated surface of the detector. We demonstrate effective rejection of all surface α events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the 0 ν β β region of interest window by an order of magnitude in the Majorana Demonstrator and will be used in the upcoming LEGEND-200 experiment.
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Affiliation(s)
- I. J. Arnquist
- Pacific Northwest National Laboratory, Richland, WA 99354 USA
| | - F. T. Avignone
- Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 USA
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - A. S. Barabash
- National Research Center “Kurchatov Institute” Institute for Theoretical and Experimental Physics, Moscow, 117218 Russia
| | - C. J. Barton
- Department of Physics, University of South Dakota, Vermillion, SD 57069 USA
| | | | - E. Blalock
- Department of Physics, North Carolina State University, Raleigh, NC 27695 USA
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
| | - B. Bos
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - M. Busch
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics, Duke University, Durham, NC 27708 USA
| | - M. Buuck
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
- Present Address: SLAC National Accelerator Laboratory, Menlo Park, CA 94025 USA
| | - T. S. Caldwell
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - Y.-D. Chan
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | | | - P.-H. Chu
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - M. L. Clark
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - C. Cuesta
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
- Present Address: Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, 28040 Madrid Spain
| | - J. A. Detwiler
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
| | - A. Drobizhev
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - T. R. Edwards
- Department of Physics, University of South Dakota, Vermillion, SD 57069 USA
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - D. W. Edwins
- Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 USA
| | - F. Edzards
- Max-Planck-Institut für Physik, 80805 Munich, Germany
- Present Address: Physik-Department, Technische Universität, 85748 Munich, Germany
| | - Y. Efremenko
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37916 USA
| | - S. R. Elliott
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - T. Gilliss
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
- Present Address: Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 USA
| | - G. K. Giovanetti
- Physics Department, Williams College, Williamstown, MA 01267 USA
| | - M. P. Green
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
- Department of Physics, North Carolina State University, Raleigh, NC 27695 USA
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
| | - J. Gruszko
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - I. S. Guinn
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | | | - C. R. Haufe
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - R. J. Hegedus
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - R. Henning
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - D. Hervas Aguilar
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - E. W. Hoppe
- Pacific Northwest National Laboratory, Richland, WA 99354 USA
| | - A. Hostiuc
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
| | - I. Kim
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - R. T. Kouzes
- Pacific Northwest National Laboratory, Richland, WA 99354 USA
| | - A. M. Lopez
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37916 USA
| | | | - E. L. Martin
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics, Duke University, Durham, NC 27708 USA
| | - R. D. Martin
- Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 Canada
| | - R. Massarczyk
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - S. J. Meijer
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - S. Mertens
- Max-Planck-Institut für Physik, 80805 Munich, Germany
- Present Address: Physik-Department, Technische Universität, 85748 Munich, Germany
| | - J. Myslik
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - T. K. Oli
- Department of Physics, University of South Dakota, Vermillion, SD 57069 USA
| | - G. Othman
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
- Universität Hamburg, 20146 Hamburg, Germany
| | - W. Pettus
- Department of Physics, Indiana University, Bloomington, IN 47405 USA
- IU Center for Exploration of Energy and Matter, Bloomington, IN 47408 USA
| | - A. W. P. Poon
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - D. C. Radford
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - J. Rager
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
- Present Address: Applied Research Associated, Raleigh, NC 27615 USA
| | - A. L. Reine
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - K. Rielage
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - N. W. Ruof
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
| | - B. Saykı
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - S. Schönert
- Present Address: Physik-Department, Technische Universität, 85748 Munich, Germany
| | - M. J. Stortini
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - D. Tedeschi
- Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 USA
| | - R. L. Varner
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - S. Vasilyev
- Joint Institute for Nuclear Research, Dubna, 141980 Russia
| | - J. F. Wilkerson
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
- Triangle Universities Nuclear Laboratory, Durham, NC 27708 USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514 USA
| | - M. Willers
- Present Address: Physik-Department, Technische Universität, 85748 Munich, Germany
| | - C. Wiseman
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, WA 98195 USA
| | - W. Xu
- Department of Physics, University of South Dakota, Vermillion, SD 57069 USA
| | - C.-H. Yu
- Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - B. X. Zhu
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
- Present Address: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
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