Study on cosmogenic activation above ground for the DarkSide-20k project

The activation of materials due to the exposure to cosmic rays may become an important background source for experiments investigating rare event phenomena. DarkSide-20k is a direct detection experiment for galactic dark matter particles, using a two-phase liquid argon time projection chamber filled with 49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Here, the cosmogenic activity of relevant long-lived radioisotopes induced in the argon and other massive components of the set-up has been estimated; production of 120 t of radiopure UAr is foreseen. The expected exposure above ground and production rates, either measured or calculated, have been considered. 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. Activation of titanium, considered in early designs but not used in the final design, is discussed. The activity of 39Ar induced during extraction, purification and transport on surface, in baseline conditions, is evaluated to be 2.8% of the activity measured in UAr from the same source, and thus considered acceptable. Other products in the UAr such as 37Ar and 3H are shown to not be relevant due to short half-life and assumed purification methods

Directionality of nuclear recoils in a liquid argon time projection chamber

The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scintillation and charge signals produced by NRs. Furthermore, the existence of a drift electric field in the TPC breaks the rotational symmetry: the angle between the drift field and the momentum of the recoiling nucleus can potentially affect the charge recombination probability in liquid argon and then the relative balance between the two signal channels. This fact could make the detector sensitive to the directionality of the WIMP-induced signal, enabling unmistakable annual and daily modulation signatures for future searches aiming for discovery. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data were taken with 72 keV NRs of known recoil directions. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/- 0.027 and the upper limit is R < 1.072 with 90% confidence levelComment: 20 pages, 10 figures, submitted to Eur. Phys. J.

Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel

Dark matter lighter than 10 GeV/c$^2$ encompasses a promising range of candidates. A conceptual design for a new detector, DarkSide-LowMass, is presented, based on the DarkSide-50 detector and progress toward DarkSide-20k, optimized for a low-threshold electron-counting measurement. Sensitivity to light dark matter is explored for various potential energy thresholds and background rates. These studies show that DarkSide-LowMass can achieve sensitivity to light dark matter down to the solar neutrino floor for GeV-scale masses and significant sensitivity down to 10 MeV/c$^2$ considering the Migdal effect or interactions with electrons. Requirements for optimizing the detector's sensitivity are explored, as are potential sensitivity gains from modeling and mitigating spurious electron backgrounds that may dominate the signal at the lowest energies

Separating Ar39 from Ar40 by cryogenic distillation with Aria for dark matter searches

Aria is a plant hosting a 350m cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of 39Ar in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed, 39Ar is a -emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant

Study on cosmogenic activation above ground for the DarkSide-20k project

International audienceThe activation of materials due to the exposure to cosmic rays may become an important background source for experiments investigating rare event phenomena. DarkSide-20k is a direct detection experiment for galactic dark matter particles, using a two-phase liquid argon time projection chamber filled with 49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Here, the cosmogenic activity of relevant long-lived radioisotopes induced in the argon and other massive components of the set-up has been estimated; production of 120 t of radiopure UAr is foreseen. The expected exposure above ground and production rates, either measured or calculated, have been considered. 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. Activation of titanium, considered in early designs but not used in the final design, is discussed. The activity of 39Ar induced during extraction, purification and transport on surface, in baseline conditions, is evaluated to be 2.8% of the activity measured in UAr from the same source, and thus considered acceptable. Other products in the UAr such as 37Ar and 3H are shown to not be relevant due to short half-life and assumed purification methods

Directionality of nuclear recoils in a liquid argon time projection chamber

International audienceThe direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scintillation and charge signals produced by NRs. Furthermore, the existence of a drift electric field in the TPC breaks the rotational symmetry: the angle between the drift field and the momentum of the recoiling nucleus can potentially affect the charge recombination probability in liquid argon and then the relative balance between the two signal channels. This fact could make the detector sensitive to the directionality of the WIMP-induced signal, enabling unmistakable annual and daily modulation signatures for future searches aiming for discovery. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data were taken with 72 keV NRs of known recoil directions. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/- 0.027 and the upper limit is R < 1.072 with 90% confidence leve

Sensitivity of future liquid argon dark matter search experiments to core-collapse supernova neutrinos

none276Future liquid-argon DarkSide-20k and Argo detectors, designed for direct dark matter search, will be sensitive also to core-collapse supernova neutrinos, via coherent elastic neutrino-nucleus scattering. This interaction channel is flavor-insensitive with a high-cross section, enabling for a high-statistics neutrino detection with target masses of ∼50 t and ∼360 t for DarkSide-20k and Argo respectively. Thanks to the low-energy threshold of ∼0.5 keVnr achievable by exploiting the ionization channel, DarkSide-20k and Argo have the potential to discover supernova bursts throughout our galaxy and up to the Small Magellanic Cloud, respectively, assuming a 11-M⊙ progenitor star. We report also on the sensitivity to the neutronization burst, whose electron neutrino flux is suppressed by oscillations when detected via charged current and elastic scattering. Finally, the accuracies in the reconstruction of the average and total neutrino energy in the different phases of the supernova burst, as well as its time profile, are also discussed, taking into account the expected background and the detector response.noneAgnes P.; Albergo S.; Albuquerque I.F.M.; Alexander T.; Alici A.; Alton A.K.; Amaudruz P.; Arcelli S.; Ave M.; Avetissov I.C.; Avetisov R.I.; Azzolini O.; Back H.O.; Balmforth Z.; Barbarian V.; Barrado Olmedo A.; Barrillon P.; Basco A.; Batignani G.; Bondar A.; Bonivento W.M.; Borisova E.; Bottino B.; Boulay M.G.; Buccino G.; Bussino S.; Busto J.; Buzulutskov A.; Cadeddu M.; Cadoni M.; Caminata A.; Canci N.; Cappello G.; Caravati M.; Cardenas-Montes M.; Carlini M.; Carnesecchi F.; Castello P.; Catalanotti S.; Cataudella V.; Cavalcante P.; Cavuoti S.; Cebrian S.; Cela Ruiz J.M.; Celano B.; Chashin S.; Chepurnov A.; Chyhyrynets E.; Cicalo C.; Cifarelli L.; Cintas D.; Coccetti F.; Cocco V.; Colocci M.; E. Conde Vilda; Consiglio L.; Copello S.; Corning J.; Covone G.; Czudak P.; D'Auria S.; Da Rocha Rolo M.D.; Dadoun O.; Daniel M.; Davini S.; De Candia A.; De Cecco S.; De Falco A.; De Filippis G.; De Gruttola D.; De Guido G.; De Rosa G.; Della Valle M.; Dellacasa G.; De Pasquale S.; Derbin A.V.; Devoto A.; Di Noto L.; Dionisi C.; Di Stefano P.; Dolganov G.; Dordei F.; Doria L.; Downing M.; Erjavec T.; Fernandez Diaz M.; Fiorillo G.; Franceschi A.; Franco D.; Frolov E.; Funicello N.; Gabriele F.; Galbiati C.; Garbini M.; Garcia Abia P.; Gendotti A.; Ghiano C.; Giampaolo R.A.; Giganti C.; Giorgi M.A.; Giovanetti G.K.; Goicoechea Casanueva V.; Gola A.; Graciani Diaz R.; Grigoriev G.Y.; Grobov A.; Gromov M.; Guan M.; Guerzoni M.; Gulino M.; Guo C.; Hackett B.R.; Hallin A.; Haranczyk M.; Hill S.; Horikawa S.; Hubaut F.; Hugues T.; Hungerford E.V.; Ianni A.; Ippolito V.; James C.C.; Jillings C.; Kachru P.; Kemp A.A.; Kendziora C.L.; Keppel G.; Khomyakov A.V.; Kim S.; Kish A.; Kochanek I.; Kondo K.; Korga G.; Kubankin A.; Kugathasan R.; Kuss M.; Kuzniak M.; La Commara M.; Lai M.; Langrock S.; Leyton M.; Li X.; Lidey L.; Lissia M.; Longo G.; Machulin I.N.; Mapelli L.; Marasciulli A.; Margotti A.; Mari S.M.; Maricic J.; Martinez M.; Martinez Rojas A.D.; Martoff C.J.; Masoni A.; Mazzi A.; McDonald A.B.; Mclaughlin J.; Messina A.; Meyers P.D.; Miletic T.; Milincic R.; Moggi A.; Moharana A.; Moioli S.; Monroe J.; Morisi S.; Morrocchi M.; Mozhevitina E.N.; Mroz T.; Muratova V.N.; Muscas C.; Musenich L.; Musico P.; Nania R.; Napolitano T.; Navrer Agasson A.; Nessi M.; Nikulin I.; Nowak J.; Oleinik A.; Oleynikov V.; Pagani L.; Pallavicini M.; Pandola L.; Pantic E.; Paoloni E.; Paternoster G.; Pegoraro P.A.; Pelczar K.; Pellegrini L.A.; Pellegrino C.; Perotti F.; Pesudo V.; Picciau E.; Pietropaolo F.; Pira C.; Pocar A.; Poehlmann D.M.; Pordes S.; Poudel S.S.; Pralavorio P.; Price D.; Raffaelli F.; Ragusa F.; Ramirez A.; Razeti M.; Razeto A.; Renshaw A.L.; Rescia S.; Rescigno M.; Resnati F.; Retiere F.; Rignanese L.P.; Ripoli C.; Rivetti A.; Rode J.; Romero L.; Rossi M.; Rubbia A.; Salatino P.; Samoylov O.; Sanchez Garcia E.; Sandford E.; Sanfilippo S.; Santone D.; Santorelli R.; Savarese C.; Scapparone E.; Schlitzer B.; Scioli G.; Semenov D.A.; Shaw B.; Shchagin A.; Sheshukov A.; Simeone M.; Skensved P.; Skorokhvatov M.D.; Smirnov O.; Smith B.; Sokolov A.; Steri A.; Stracka S.; Strickland V.; Stringer M.; Sulis S.; Suvorov Y.; Szelc A.M.; Tartaglia R.; Testera G.; Thorpe T.N.; Tonazzo A.; Torres-Lara S.; Tricomi A.; Unzhakov E.V.; Usai G.; Vallivilayil John T.; Viant T.; Viel S.; Vishneva A.; Vogelaar R.B.; Wada M.; Wang H.; Wang Y.; Westerdale S.; Wheadon R.J.; Williams L.; Wojcik M.M.; Wojcik M.; Xiao X.; Yang C.; Ye Z.; Zani A.; Zichichi A.; Zuzel G.; Zykova M.P.Agnes, P.; Albergo, S.; Albuquerque, I. F. M.; Alexander, T.; Alici, A.; Alton, A. K.; Amaudruz, P.; Arcelli, S.; Ave, M.; Avetissov, I. C.; Avetisov, R. I.; Azzolini, O.; Back, H. O.; Balmforth, Z.; Barbarian, V.; Barrado Olmedo, A.; Barrillon, P.; Basco, A.; Batignani, G.; Bondar, A.; Bonivento, W. M.; Borisova, E.; Bottino, B.; Boulay, M. G.; Buccino, G.; Bussino, S.; Busto, J.; Buzulutskov, A.; Cadeddu, M.; Cadoni, M.; Caminata, A.; Canci, N.; Cappello, G.; Caravati, M.; Cardenas-Montes, M.; Carlini, M.; Carnesecchi, F.; Castello, P.; Catalanotti, S.; Cataudella, V.; Cavalcante, P.; Cavuoti, S.; Cebrian, S.; Cela Ruiz, J. M.; Celano, B.; Chashin, S.; Chepurnov, A.; Chyhyrynets, E.; Cicalo, C.; Cifarelli, L.; Cintas, D.; Coccetti, F.; Cocco, V.; Colocci, M.; E., Conde Vilda; Consiglio, L.; Copello, S.; Corning, J.; Covone, G.; Czudak, P.; D'Auria, S.; Da Rocha Rolo, M. D.; Dadoun, O.; Daniel, M.; Davini, S.; De Candia, A.; De Cecco, S.; De Falco, A.; De Filippis, G.; De Gruttola, D.; De Guido, G.; De Rosa, G.; Della Valle, M.; Dellacasa, G.; De Pasquale, S.; Derbin, A. V.; Devoto, A.; Di Noto, L.; Dionisi, C.; Di Stefano, P.; Dolganov, G.; Dordei, F.; Doria, L.; Downing, M.; Erjavec, T.; Fernandez Diaz, M.; Fiorillo, G.; Franceschi, A.; Franco, D.; Frolov, E.; Funicello, N.; Gabriele, F.; Galbiati, C.; Garbini, M.; Garcia Abia, P.; Gendotti, A.; Ghiano, C.; Giampaolo, R. A.; Giganti, C.; Giorgi, M. A.; Giovanetti, G. K.; Goicoechea Casanueva, V.; Gola, A.; Graciani Diaz, R.; Grigoriev, G. Y.; Grobov, A.; Gromov, M.; Guan, M.; Guerzoni, M.; Gulino, M.; Guo, C.; Hackett, B. R.; Hallin, A.; Haranczyk, M.; Hill, S.; Horikawa, S.; Hubaut, F.; Hugues, T.; Hungerford, E. V.; Ianni, A.; Ippolito, V.; James, C. C.; Jillings, C.; Kachru, P.; Kemp, A. A.; Kendziora, C. L.; Keppel, G.; Khomyakov, A. V.; Kim, S.; Kish, A.; Kochanek, I.; Kondo, K.; Korga, G.; Kubankin, A.; Kugathasan, R.; Kuss, M.; Kuzniak, M.; La Commara, M.; Lai, M.; Langrock, S.; Leyton, M.; Li, X.; Lidey, L.; Lissia, M.; Longo, G.; Machulin, I. N.; Mapelli, L.; Marasciulli, A.; Margotti, A.; Mari, S. M.; Maricic, J.; Martinez, M.; Martinez Rojas, A. D.; Martoff, C. J.; Masoni, A.; Mazzi, A.; Mcdonald, A. B.; Mclaughlin, J.; Messina, A.; Meyers, P. D.; Miletic, T.; Milincic, R.; Moggi, A.; Moharana, A.; Moioli, S.; Monroe, J.; Morisi, S.; Morrocchi, M.; Mozhevitina, E. N.; Mroz, T.; Muratova, V. N.; Muscas, C.; Musenich, L.; Musico, P.; Nania, R.; Napolitano, T.; Navrer Agasson, A.; Nessi, M.; Nikulin, I.; Nowak, J.; Oleinik, A.; Oleynikov, V.; Pagani, L.; Pallavicini, M.; Pandola, L.; Pantic, E.; Paoloni, E.; Paternoster, G.; Pegoraro, P. A.; Pelczar, K.; Pellegrini, L. A.; Pellegrino, C.; Perotti, F.; Pesudo, V.; Picciau, E.; Pietropaolo, F.; Pira, C.; Pocar, A.; Poehlmann, D. M.; Pordes, S.; Poudel, S. S.; Pralavorio, P.; Price, D.; Raffaelli, F.; Ragusa, F.; Ramirez, A.; Razeti, M.; Razeto, A.; Renshaw, A. L.; Rescia, S.; Rescigno, M.; Resnati, F.; Retiere, F.; Rignanese, L. P.; Ripoli, C.; Rivetti, A.; Rode, J.; Romero, L.; Rossi, M.; Rubbia, A.; Salatino, P.; Samoylov, O.; Sanchez Garcia, E.; Sandford, E.; Sanfilippo, S.; Santone, D.; Santorelli, R.; Savarese, C.; Scapparone, E.; Schlitzer, B.; Scioli, G.; Semenov, D. A.; Shaw, B.; Shchagin, A.; Sheshukov, A.; Simeone, M.; Skensved, P.; Skorokhvatov, M. D.; Smirnov, O.; Smith, B.; Sokolov, A.; Steri, A.; Stracka, S.; Strickland, V.; Stringer, M.; Sulis, S.; Suvorov, Y.; Szelc, A. M.; Tartaglia, R.; Testera, G.; Thorpe, T. N.; Tonazzo, A.; Torres-Lara, S.; Tricomi, A.; Unzhakov, E. V.; Usai, G.; Vallivilayil John, T.; Viant, T.; Viel, S.; Vishneva, A.; Vogelaar, R. B.; Wada, M.; Wang, H.; Wang, Y.; Westerdale, S.; Wheadon, R. J.; Williams, L.; Wojcik, M. M.; Wojcik, M.; Xiao, X.; Yang, C.; Ye, Z.; Zani, A.; Zichichi, A.; Zuzel, G.; Zykova, M. P