Study of cosmogenic activation above ground for the DarkSide-20k experiment

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 gamma/beta 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.Comment: As accepted for publication at Astroparticle Physic

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: Ar$^{36}$, Ar$^{38}$, and Ar$^{40}$. We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: Ar$^{36}$, Ar$^{38}$, and Ar$^{40}$. We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019

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.

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: 36Ar , 38Ar , and 40Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019.ISSN:1434-6044ISSN:1434-605

Separating 39Ar from 40Ar 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.ISSN:1434-6044ISSN:1434-605

Constraints on directionality effect 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 produced in a target material from the WIMP elastic scattering. The experimental identification of the direction of the WIMP-induced nuclear recoils is a crucial asset in this field, as it enables unmistakable modulation signatures for dark matter. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity in argon dual-phase time projection chambers (TPC), that are widely considered for current and future direct dark matter searches. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud. Data were taken with nuclear recoils of known directions and kinetic energy of 72 keV, which is within the range of interest for WIMP-induced signals in argon. 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 R< 1.072 with 90 % confidence level.ISSN:1434-6044ISSN:1434-605

SiPM-matrix readout of two-phase argon detectors using electroluminescence in the visible and near infrared range

Proportional electroluminescence (EL) in noble gases is used in two-phase detectors for dark matter searches to record (in the gas phase) the ionization signal induced by particle scattering in the liquid phase. The “standard” EL mechanism is considered to be due to noble gas excimer emission in the vacuum ultraviolet (VUV). In addition, there are two alternative mechanisms, producing light in the visible and near infrared (NIR) ranges. The first is due to bremsstrahlung of electrons scattered on neutral atoms (“neutral bremsstrahlung”, NBrS). The second, responsible for electron avalanche scintillation in the NIR at higher electric fields, is due to transitions between excited atomic states. In this work, we have for the first time demonstrated two alternative techniques of the optical readout of two-phase argon detectors, in the visible and NIR range, using a silicon photomultiplier matrix and electroluminescence due to either neutral bremsstrahlung or avalanche scintillation. The amplitude yield and position resolution were measured for these readout techniques, which allowed to assess the detection threshold for electron and nuclear recoils in two-phase argon detectors for dark matter searches. To the best of our knowledge, this is the first practical application of the NBrS effect in detection science.ISSN:1434-6044ISSN:1434-605

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

International audienceThe Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: Ar$^{36}$, Ar$^{38}$, and Ar$^{40}$. We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019

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