Darkside

Abstract

DarkSide-50 is a dual-phase argon Time Projection Chamber (TPC), developed for use in a search for direct evidence of dark matter. The experiment is hosted in Hall C of the Laboratori Nazionali del Gran Sasso, underneath the Gran Sasso e Monti della Laga National Park, and has been collecting data since October 2013.
DS-20k is a two-phase LAr detector with a 50 tonnes active volume. It will be installed in LNGS Hall-C in 2022 and will either detect WIMP dark matter or reach a 90% exclusion sensitivity to WIMP-nucleon cross sections of 7.4x10^-48cm² at the mass of 1TeV/c².

Description of the detector and related techniques

DarkSide-50 is a dual-phase argon TPC. Thirty-eight 3" Hamamatsu low-background R11065 PMTs (photomultiplier tubes), 19 each on the top and the bottom, view the active region through fused silica windows. The windows are coated on both sides with Indium Tin Oxide, ITO, a transparent conductor. This allows the inner window surfaces to serve as the grounded anode (top) and -60 KV cathode (bottom) of the TPC while maintaining their outer surfaces near the -1.5 KV PMT photocathode potential.
A gas layer for production of the electroluminescence signature is provided by a cylindrical rim on the fused silica anode window, which extends downward to form a “diving bell” containing the 2 cm-thick argon vapor layer (“gas pocket”) above the TPC drift volume. The cylindrical vessel containing the active region is made of PTFE, treated to be highly reflective at visible wavelengths. The entire inner surface of the active volume is coated with the wavelength shifter TetraPhenylButadiene (TPB) to convert the 128 nm argon scintillation into the wavelength range detectable by the PMTs. The drift field is produced by system consisting of the ITO cathode and anode planes, a field cage, and a grid that separates the drift and electron extraction regions.
The DarkSide-50 TPC is deployed within a borated liquid scintillator-based neutron veto, which is in turn inside a water Cherenkov muon veto. This not only gave DarkSide-50 the benefits of active background suppression, but also provided the direct experience in operating a low background experiment in these active shields, in preparation for future upgrades.

DS-20k detector consists of two nested detectors housed within a ProtoDUNE-style membrane cryostat. It is foreseen to begin operations in 2023 and will either detect WIMP dark matter or exclude a large fraction of favored WIMP parameter space, to WIMP-nucleon cross sections of 7.4x10^-48cm² for a 1TeV/c² mass.
The inner detector is a dual-phase argon time projection chamber (LAr TPC) contained within a vessel made from ultra-pure acrylic (PMMA) filled with ultra low-radioactivity Argon from Underground sources (UAr) and readout by 8280 SiPM-based PhotoDetector Modules (PDM) arrays. The height of the TPC is 350 cm and the total mass of UAr in the active volume is 49.7 t.
The outer veto detector is made of a passive Gd-loaded PMMA shell surrounding the inner detector, and of an outer copper faraday cage. As a result, the volume contained in the ProtoDUNE-style cryostat is subdivided in three different volumes, requiring a fill of 760 tonnes of liquid Argon from the Atmosphere (AAr). All three volumes are equipped with PDMs and will be operated as anticoincidence veto detectors, reducing at once background from cosmic rays and from neutrons and gamma-rays sourced by the construction materials of the detector.
DarkSide-20k is designed to operate with zero backgrounds, meaning that all sources of instrumental background are reduced to <0.1 events over a 200 t yr exposure. All background from minimum-ionizing radiation sources will be completely removed thanks to the combined action of the Pulse Shape Discrimination (PSD) of the primary scintillation and comparison of the primary and secondary scintillation. This outstanding sensitivity to coherent nuclear recoils will enable DarkSide-20k to detect a supernova neutrino burst coming from anywhere in the Milky Way Galaxy and, for a majority of the galaxy, clearly identify the neutronization burst, thus performing a flavor-blind measurement of the total neutrino flux and average energy.

Spokesperson
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Deputy Spokesperson
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DarkSide-50 Collaboration (2019)

P. Agnes,¹ I.F.M. Albuquerque,² T. Alexander,³ A.K. Alton,⁴ M. Ave,² H.O. Back,³ G. Batignani,⁵, ⁶ K. Biery,⁷ V. Bocci,⁸ G. Bonfini,⁹ W.M. Bonivento,¹⁰ B. Bottino,¹¹, ¹² S. Bussino,¹³, ¹⁴ M. Cadeddu,¹⁵, ¹⁰ M. Cadoni,^{15, 10} F. Calaprice,¹⁶ A. Caminata,¹² N. Canci,^{1, 9} A. Candela,⁹ M. Caravati,^{15, 10} M. Cariello,¹² M. Carlini,^{9, 17} M. Carpinelli,^{18, 19} S. Catalanotti,^{20, 21} V. Cataudella,^{20, 21} P. Cavalcante,^{22, 9} S. Cavuoti,^{20, 21} A. Chepurnov,²³ C. Cicalò,¹⁰ A.G. Cocco,²¹ G. Covone,^{20, 21} D. D’Angelo,^{24, 25} M. D’Incecco,⁹ D. D’Urso,^{18, 19} S. Davini,¹² A. De Candia,^{20, 21} S. De Cecco,^{8, 26} M. De Deo,⁹ G. De Filippis,^{20, 21} G. De Rosa,^{20, 21} A.V. Derbin,²⁷ A. Devoto,^{15, 10} F. Di Eusanio,^{16, 22} G. Di Pietro,^{9, 25} C. Dionisi,^{8, 26} M. Downing,²⁸ E. Edkins,²⁹ A. Empl,¹ G. Fiorillo,^20, ²¹ K. Fomenko,³⁰ D. Franco,³¹ F. Gabriele,⁹ C. Galbiati,^{16, 17} C. Ghiano,⁹ S. Giagu,^{8, 26} C. Giganti,³² G.K. Giovanetti,¹⁶ O. Gorchakov,³⁰ A.M. Goretti,⁹ F. Granato,³³ A. Grobov,^{34, 35} M. Gromov,^{23, 30} M. Guan,³⁶ Y. Guardincerri,⁷, a M. Gulino,^{37, 19} B.R. Hackett,²⁹ K. Herner,⁷ B. Hosseini,¹⁰ D. Hughes,¹⁶ P. Humble,³ E.V. Hungerford,¹ Al. Ianni,⁹ An. Ianni,^{16, 9} V. Ippolito,⁸ T.N. Johnson,³⁸ K. Keeter,³⁹ C.L. Kendziora,⁷ I. Kochanek,⁹ G. Koh,¹⁶ D. Korablev,³⁰ G. Korga,^{1, 9} A. Kubankin,⁴⁰ M. Kuss,⁵ M. La Commara,^{20, 21} M. Lai,^{15, 10} X. Li,¹⁶ M. Lissia,¹⁰ G. Longo,^{20, 21} A.A. Machado,⁴¹ I.N. Machulin,^34,³⁵ A. Mandarano,^{17, 9} L. Mapelli,¹⁶ S.M. Mari,^{13, 14} J. Maricic,²⁹ C.J. Martoff,³³ A. Messina,^{8, 26} P.D. Meyers,¹⁶ R. Milincic,²⁹ A. Monte,^{7, 28} M. Morrocchi,^{5, 6} V.N. Muratova,²⁷ P. Musico,¹² A. Navrer Agasson,³² A.O. Nozdrina,^{34, 35} A. Oleinik,⁴⁰ M. Orsini,⁹ F. Ortica,^{42, 43} L. Pagani,³⁸ M. Pallavicini,^{11, 12} L. Pandola,¹⁹ E. Pantic,³⁸ E. Paoloni,^5, ⁶ K. Pelczar,^{9, 44} N. Pelliccia,^{42, 43} E. Picciau,^{15, 10} A. Pocar,²⁸ S. Pordes,⁷ S.S. Poudel,¹ H. Qian,¹⁶ F. Ragusa,^24, ²⁵ M. Razeti,¹⁰ A. Razeto,⁹ A.L. Renshaw,¹ M. Rescigno,⁸ Q. Riffard,³¹ A. Romani,^{42, 43} B. Rossi,²¹ N. Rossi,⁹ D. Sablone,^{16, 9} O. Samoylov,³⁰ W. Sands,¹⁶ S. Sanfilippo,^{14, 13} C. Savarese,^{17, 9, 16} B. Schlitzer,³⁸ E. Segreto,⁴¹ D.A. Semenov,²⁷ A. Shchagin,⁴⁰ A. Sheshukov,³⁰ P.N. Singh,¹ M.D. Skorokhvatov,^34, ³⁵ O. Smirnov,³⁰ A. Sotnikov,³⁰ C. Stanford,¹⁶ S. Stracka,⁵ Y. Suvorov,^{20, 21, 34} R. Tartaglia,⁹ G. Testera,¹² A. Tonazzo,³¹ P. Trinchese,^{20, 21} E.V. Unzhakov,²⁷ M. Verducci,^8, ²⁶ A. Vishneva,³⁰ R.B. Vogelaar,²² M. Wada,^{16, 10} T.J. Waldrop,⁴ H. Wang,⁴⁵ Y. Wang,⁴⁵ A.W. Watson,³³ S. Westerdale,¹⁶ M.M. Wojcik,⁴⁴ X. Xiang,¹⁶ X. Xiao,⁴⁵ C. Yang,³⁶ Z. Ye,¹ C. Zhu,¹⁶ and G. Zuzel ⁴⁴

¹Department of Physics, University of Houston, Houston, TX 77204, USA

²Instituto de Física, Universidade de Sao Paulo, Sao Paulo 05508-090, Brazil

³Pacific Northwest National Laboratory, Richland, WA 99352, USA

⁴Physics Department, Augustana University, Sioux Falls, SD 57197, USA

⁵INFN Pisa, Pisa 56127, Italy

⁶Physics Department, Università degli Studi di Pisa, Pisa 56127, Italy

⁷Fermi National Accelerator Laboratory, Batavia, IL 60510, USA

⁸INFN Sezione di Roma, Roma 00185, Italy

⁹INFN Laboratori Nazionali del Gran Sasso, Assergi (AQ) 67100, Italy

¹⁰INFN Cagliari, Cagliari 09042, Italy

¹¹Physics Department, Università degli Studi di Genova, Genova 16146, Italy

¹²INFN Genova, Genova 16146, Italy

¹³INFN Roma Tre, Roma 00146, Italy

¹⁴Mathematics and Physics Department, Università degli Studi Roma Tre, Roma 00146, Italy

¹⁵Physics Department, Università degli Studi di Cagliari, Cagliari 09042, Italy

¹⁶Physics Department, Princeton University, Princeton, NJ 08544, USA

¹⁷Gran Sasso Science Institute, L’Aquila 67100, Italy

¹⁸Chemistry and Pharmacy Department, Università degli Studi di Sassari, Sassari 07100, Italy

¹⁹INFN Laboratori Nazionali del Sud, Catania 95123, Italy

²⁰Physics Department, Università degli Studi “Federico II” di Napoli, Napoli 80126, Italy

²¹INFN Napoli, Napoli 80126, Italy

²²Virginia Tech, Blacksburg, VA 24061, USA

²³Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119234, Russia

²⁴Physics Department, Università degli Studi di Milano, Milano 20133, Italy

²⁵INFN Milano, Milano 20133, Italy

²⁶Physics Department, Sapienza Università di Roma, Roma 00185, Italy

²⁷Saint Petersburg Nuclear Physics Institute, Gatchina 188350, Russia

²⁸Amherst Center for Fundamental Interactions and Physics

Department, University of Massachusetts, Amherst, MA 01003, USA

²⁹Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, USA

³⁰Joint Institute for Nuclear Research, Dubna 141980, Russia

³¹APC, Université Paris Diderot, CNRS/IN²P³, CEA/Irfu, Obs de Paris, USPC, Paris 75205, France

³²LPNHE, CNRS/IN²P³, Sorbonne Université, Université Paris Diderot, Paris 75252, France

³³Physics Department, Temple University, Philadelphia, PA 19122, USA

³⁴National Research Centre Kurchatov Institute, Moscow 123182, Russia

³⁵National Research Nuclear University MEPhI, Moscow 115409, Russia

³⁶Institute of High Energy Physics, Beijing 100049, China

³⁷Engineering and Architecture Faculty, Universita` di Enna Kore, Enna 94100, Italy

³⁸Department of Physics, University of California, Davis, CA 95616, USA

³⁹School of Natural Sciences, Black Hills State University, Spearfish, SD 57799, USA

⁴⁰Radiation Physics Laboratory, Belgorod National Research University, Belgorod 308007, Russia

⁴¹Physics Institute, Universidade Estadual de Campinas, Campinas 13083, Brazil

⁴²Chemistry, Biology and Biotechnology Department, Università degli Studi di Perugia, Perugia 06123, Italy
⁴³INFN Perugia, Perugia 06123, Italy

⁴⁴M. Smoluchowski Institute of Physics, Jagiellonian University, 30-348 Krakow, Poland

⁴⁵Physics and Astronomy Department, University of California, Los Angeles, CA 90095, USA

Recent publications

P. Agnes et al. “First results from the DarkSide-50dark matter experiment at Laboratori Nazionali del Gran Sasso”. Physics Letters B, 743: 456-466 (2015).

P. Agnes et al. “Results from the first use of low radioactivity argon in a dark matter search”. Physical Review D, 93: 081101(R) (2016).

J. Xu et al. “A study of the trace 39Ar content in argon from deep underground sources”. Astroparticle Physics, 66: 53-60 (2015).

P. Agnes et al. "DarkSide-50 532-day dark matter search with low-radioactivity argon", Physical Review D 98, 102006 (2018).

P. Agnes et al. "Low-Mass Dark Matter Search with the DarkSide-50 Experiment", Physical Review Letters 121, 081307 (2018).

P. Agnes et al. "Constraints on Sub-GeV Dark-Matter–Electron Scattering from the DarkSide-50 Experiment", Physical Review Letters 121, 111303 (2018).

Official website
http://darkside.lngs.infn.it/