TY - JOUR
T1 - Study of cosmogenic activation above ground for the DarkSide-20k experiment
AU - The DarkSide-20k collaboration
AU - Elersich, A.
AU - Agnes, P.
AU - Ahmad, I.
AU - Albergo, S.
AU - Albuquerque, I. F.M.
AU - Alexander, T.
AU - Alton, A. K.
AU - Amaudruz, P.
AU - Atzori Corona, M.
AU - Ave, M.
AU - Avetisov, I. Ch
AU - Azzolini, O.
AU - Back, H. O.
AU - Balmforth, Z.
AU - Barrado-Olmedo, A.
AU - Barrillon, P.
AU - Basco, A.
AU - Batignani, G.
AU - Bocci, V.
AU - Bonivento, W. M.
AU - Bottino, B.
AU - Boulay, M. G.
AU - Busto, J.
AU - Cadeddu, M.
AU - Caminata, A.
AU - Canci, N.
AU - Capra, A.
AU - Caprioli, S.
AU - Caravati, M.
AU - Cargioli, N.
AU - Carlini, M.
AU - Castello, P.
AU - Cavalcante, P.
AU - Cavuoti, S.
AU - Cebrian, S.
AU - Cela Ruiz, J. M.
AU - Chashin, S.
AU - Chepurnov, A.
AU - Chyhyrynets, E.
AU - Cifarelli, L.
AU - Cintas, D.
AU - Citterio, M.
AU - Cleveland, B.
AU - Cocco, V.
AU - Colaiuda, D.
AU - Conde Vilda, E.
AU - Consiglio, L.
AU - Copello, S.
AU - Covone, G.
AU - Galbiati, C.
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023/10
Y1 - 2023/10
N2 - The activation of materials due to exposure to cosmic rays may become an important background source for experiments investigating rare event phenomena. DarkSide-20k, currently under construction at the Laboratori Nazionali del Gran Sasso, is a direct detection experiment for galactic dark matter particles, using a two-phase liquid-argon Time Projection Chamber (TPC) filled with 49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Despite the outstanding capability of discriminating γ/β background in argon TPCs, this background must be considered because of induced dead time or accidental coincidences mimicking dark-matter signals and it is relevant for low-threshold electron-counting measurements. Here, the cosmogenic activity of relevant long-lived radioisotopes induced in the experiment has been estimated to set requirements and procedures during preparation of the experiment and to check that it is not dominant over primordial radioactivity; particular attention has been paid to the activation of the 120 t of UAr used in DarkSide-20k. Expected exposures above ground and production rates, either measured or calculated, have been considered in detail. From the simulated counting rates in the detector due to cosmogenic isotopes, it is concluded that activation in copper and stainless steel is not problematic. The activity of 39Ar induced during extraction, purification and transport on surface is evaluated to be 2.8% of the activity measured in UAr by DarkSide-50 experiment, which used the same underground source, and thus considered acceptable. Other isotopes in the UAr such as 37Ar and 3H are shown not to be relevant due to short half-life and assumed purification methods.
AB - The activation of materials due to exposure to cosmic rays may become an important background source for experiments investigating rare event phenomena. DarkSide-20k, currently under construction at the Laboratori Nazionali del Gran Sasso, is a direct detection experiment for galactic dark matter particles, using a two-phase liquid-argon Time Projection Chamber (TPC) filled with 49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Despite the outstanding capability of discriminating γ/β background in argon TPCs, this background must be considered because of induced dead time or accidental coincidences mimicking dark-matter signals and it is relevant for low-threshold electron-counting measurements. Here, the cosmogenic activity of relevant long-lived radioisotopes induced in the experiment has been estimated to set requirements and procedures during preparation of the experiment and to check that it is not dominant over primordial radioactivity; particular attention has been paid to the activation of the 120 t of UAr used in DarkSide-20k. Expected exposures above ground and production rates, either measured or calculated, have been considered in detail. From the simulated counting rates in the detector due to cosmogenic isotopes, it is concluded that activation in copper and stainless steel is not problematic. The activity of 39Ar induced during extraction, purification and transport on surface is evaluated to be 2.8% of the activity measured in UAr by DarkSide-50 experiment, which used the same underground source, and thus considered acceptable. Other isotopes in the UAr such as 37Ar and 3H are shown not to be relevant due to short half-life and assumed purification methods.
KW - Argon
KW - Cosmogenic activation
KW - Dark matter
KW - Rare events
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U2 - 10.1016/j.astropartphys.2023.102878
DO - 10.1016/j.astropartphys.2023.102878
M3 - Article
AN - SCOPUS:85164302182
SN - 0927-6505
VL - 152
JO - Astroparticle Physics
JF - Astroparticle Physics
M1 - 102878
ER -