Measurement of the gamma ray background in the Davis Cavern at the Sanford Underground Research Facility

Abstract

Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from γ-rays emitted by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4,850-foot level. In order to characterise the cavern background, in-situ γ-ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0--3300~keV) varied from 596~Hz to 1355~Hz for unshielded measurements, corresponding to a total flux in the cavern of 1.9±0.4~γ cm−2s−1. The resulting activity in the walls of the cavern can be characterised as 220±60~Bq/kg of 40K, 29±15~Bq/kg of 238U, and 13±3~Bq/kg of 232Th.

Metadata

Authors/Creators:

Akerib, D.S.
Akerlof, C.W.
Alsum, S.K.
Angelides, A.
Araújo, H.M.
Armstrong, J.E.
Arthurs, M.
Bai, X.
Balajthy, J.
Balashov, S.
Baxter, A.
Bernard, E.P.
Biekert, A.
Biesiadzinski, T.P.
Boast, K.
Boxer, B.
Brás, P.
Buckley, J.H.
Bugaev, V.V.
Burdin, S.
Busenitz, J.K.
Carels, C.
Carlsmith, D.L.
Carmona-Benitez, M.C.
Cascella, M.
Chan, C.
Cole, A.
Cottle, A.
Cutter, J.E.
Dahl, C.E.
Viveiros, L.D.
Dobson, J.E.Y.
Druszkiewicz, E.
Edberg, T.K.
Fan, A.
Fiorucci, S.
Flaecher, H.
Fruth, T.
Gaitskell, R.J.
Genovesi, J.
Ghag, C.
Gilchriese, M.G.D.
Gokhale, S.
van der Grinten, M.G.D.
Hall, C.R.
Hans, S.
Harrison, J.
Haselschwardt, S.J.
Hertel, S.A.
Hor, J.Y.-K.
Horn, M.
Huang, D.Q.
Ignarra, C.M.
Jahangir, O.
Ji, W.
Johnson, J.
Kaboth, A.C.
Kamdin, K.
Khaitan, D.
Khazov, A.
Kim, W.T.
Kocher, C.D.
Korley, L.
Korolkova, E.V.
Kras, J.
Kraus, H.
Kravitz, S.W.
Kreczko, L.
Krikler, B.
Kudryavtsev, V.A. https://orcid.org/0000-0002-7018-5827
Leason, E.A.
Lee, J.
Leonard, D.S.
Lesko, K.T.
Levy, C.
Li, J.
Liao, J.
Liao, F.-T.
Lin, J.
Lindote, A.
Linehan, R.
Lippincott, W.H.
Liu, R.
Liu, X.
Loniewski, C.
Lopes, M.I.
Paredes, B.L.
Lorenzon, W.
Luitz, S.
Lyle, J.M.
Majewski, P.A.
Manalaysay, A.
Manenti, L.
Mannino, R.L.
Marangou, N.
Marzioni, M.F.
McKinsey, D.N.
McLaughlin, J.
Meng, Y.
Miller, E.H.
Monzani, M.E.
Morad, J.A.
Morrison, E.
Mount, B.J.
Murphy, A.S.J.
Naim, D.
Naylor, A.
Nedlik, C.
Nehrkorn, C.
Nelson, H.N.
Neves, F.
Nikoleyczik, J.
Nilima, A.
Olcina, I.
Oliver-Mallory, K.C.
Pal, S.
Palladino, K.J.
Pease, E.K.
Penning, B.P.
Pereira, G.
Piepke, A.
Pushkin, K.
Reichenbacher, J.
Rhyne, C.A.
Riffard, Q.
Rischbieter, G.R.C.
Rodrigues, J.P.
Rosero, R.
Rossiter, P.
Rutherford, G.
Sazzad, A.B.M.R.
Schnee, R.W.
Schubnell, M.
Scovell, P.R.
Seymour, D.
Shaw, S.
Shutt, T.A.
Silk, J.J.
Silva, C.
Solmaz, M.
Solovov, V.N.
Sorensen, P.
Stancu, I.
Stevens, A.
Stiegler, T.M.
Stifter, K.
Szydagis, M.
Taylor, W.C.
Taylor, R.
Temples, D.
Terman, P.A.
Tiedt, D.R.
Timalsina, M.
Tomás, A.
Tripathi, M.
Tvrznikova, L.
Utku, U.
Uvarov, S.
Vacheret, A.
Wang, J.J.
Watson, J.R.
Webb, R.C.
White, R.G.
Whitis, T.J.
Wolfs, F.L.H.
Woodward, D.
Yin, J.

© 2019 Elsevier B.V. This is an author produced version of a paper subsequently published in Astroparticle Physics. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Keywords:

Dark matter; Low background; Radiation; Underground; Gamma rays; Gamma spectroscopy

Dates:

Accepted: 27 September 2019
Published (online): 4 October 2019
Published: March 2020

Institution:

The University of Sheffield

Academic Units:

The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield)

Funding Information:

Funder	Grant number
SCIENCE AND TECHNOLOGY FACILITIES COUNCIL	ST/M003469/1
SCIENCE AND TECHNOLOGY FACILITIES COUNCIL	ST/N001141/1
SCIENCE AND TECHNOLOGY FACILITIES COUNCIL	ST/N000277/1
Science and Technology Facilities Council	ST/N000277/1
SCIENCE AND TECHNOLOGY FACILITIES COUNCIL	ST/P00573X/1