Highlights from Gran LNGSSasso Laboratory INFN Gran Sasso
Highlights from Gran LNGSSasso Laboratory INFN Gran Sasso National Laboratory Lucia Votano – LNGS
Why Underground Laboratories Ø The physics of the earliest state of our Universe, when the fundamental forces were unified and the particles were interacting at energy not accessible to present accelerators, can be assessed by searching for very rare phenomena in matter and weak effects of elusive particles. Ø Searches for rare events like 0νDBD or proton decay, the study of weak interactions from cosmic or artificial neutrinos, the direct detection of dark matter candidates and nuclear astrophysics require low-background enviroments. Ø Thanks to the rock coverage and the corresponding reduction in the cosmic ray flux and c. r. -spallation induced neutrons, underground laboratories provide the necessary low background environment to investigate these processes. Ø Underground Laboratories are the main infrastructures for astroparticle and neutrino physics 6/8/2021 2
Gran Sasso Laboratory Ø Largest underground laboratory in the world § § Run by INFN under the Gran Sasso Mountain, Italy 120 km far from Rome, completed 1987 International scientific community (1000 users per year) Permanent staff: 82 + 19 temporary positions
Gran Sasso Laboratory 3 main halls A B C ~100 x 20 m 2 (h 20 m) Muon Flux 3. 0 10 -4 μ m-2 s-1 Neutron Flux 2. 92 10 -6 n cm-2 s-1 (0 -1 ke. V) 0. 86 10 -6 n cm-2 s-1 (> 1 ke. V) Depth: 1400 m (3800 m w. e. ) Surface: 17800 m 2 Volume: 180000 m 3 Rn in air: 20 -80 Bq/m 3 External facilities ISO 14001 Ventilation: 1 Lab volume/3 h Electrical power: 1300 k. W Access: horizontal
Physics at LNGS DAMA/LIBRA CRESST XENON CTF-Dark Side The inventory of Universe and the dark matter LBL - CNGS OPERA Icarus T 600 2 0 Properties of neutrinos and their role in cosmic evolution What about the interior of the Sun and the Earth LVD BOREXINO LUNA What about the supernova explosions CUORE GERDA COBRA Lucifer R&D
Gran Sasso Laboratory Research activities: Ø Dark matter searches Ø Neutrino physics Ø Nuclear Astrophysics Ø Associate Sciences: Environmental Radioactivity for Earth Sciences, Geophysics, Fundamental Physics, Biology
OCCUPANCY XENON 1 T CRESST GERDA LUNA CUORE LVD XENON WARP ERMES GIGS ICARUS CTF-DS-10 R&D BOREXINO VIP OPERA COBRA DAMA/LIBRA LOW ACTIVITY LAB
The dark side of the Universe. . .
Dark Matter ü Evidence of large abundance in the Universe of non-baryonic and non -relativistic “dark matter” comes from gravitational effects, also supported by measurements of the cosmic microwave background anisotropy ü Stable, Weakly Interacting Massive Particles, predicted by a number of theories beyond the SM, are candidates for DM. WIMPs could have been produced thermally in the early Universe and persist to the present day. Under this hypothesis the Earth is embedded within a WIMP gas. ü Direct detection of DM aims to observe the scattering of DM particle off target nuclei. WIMPs-target nuclei interactions produce exponentially falling differential energy spectra with energy deposition up to several- to several tens-of Ke. V. Very low rates expected (a few counts/kg/day- to a few counts/kg/year)
Dark Matter @ LNGS Different methods and techniques towards a “smoking gun” signature Noble liquids Ionization XENON 100 XENON 1 t CTF-Dark. Side R&D Crystals Na. I 250 kg Scintillation Heat DAMA/LIBRA Bolometric Cryogenic Ca. WO 4 CRESST
DM status and perspectives Rich experimental program at LNGS in the next years many complementary techniques and target materials available DAMA/LIBRA continue observations on annual modulation with improved set-up (lower energy threshold) Liquid XENON Xenon 100: Running, new results expected in 2012 XENON 1 T: approved by INFN and LNGS SC, location: Hall B, MOU signed, installation will start by 2012 Liquid Argon Technology Pioneered by Warp, cont. with Dark. Side-10 and CTF-Dark. Side R&D towards Dark. Side-50 CRESST Running, new results shown last September submitted to EPJC precursor of the next-generation dark matter project EURECA
Neutrino physics @ LNGS Ø Solar neutrinos § § 7 Be the main target for Borexino 8 B, pep, CNO, and possibly pp Ø Geo anti-neutrinos (Borexino) Ø CNGS neutrinos § OPERA and ICARUS Ø Super. Nova neutrinos § LVD, Borexino and ICARUS § LVD and Borexino are in the SNEWS network Ø Basic neutrino properties § 0 DBD
0 experiments Oscillation experiments have clearly demonstrated that: üneutrinos ( e, , t) do oscillate üneutrinos ( 1, 2, 3) are massive New Physics beyond SM must exist Oscillation experiment cannot answer to: 1. neutrinos are Dirac or Majorana particles? 2. what is the absolute mass scale and mass hierarchy? 0 experiments can answer to 1. and 2.
2 2 and 0 2 decay (A, Z+1) 2 2 decay: (A, Z) (A, Z+2) +2 e-+2 (A, Z) SM allowed & observed on several isotopes with forbidden single-. Conserves lepton number, but long half-life because 2 nd order (1019 ÷ 1021 y) (A, Z+2) 0 2 decay: (A, Z) (A, Z+2) +2 e- n p W L = Violates lepton number by two units. Possible only if R Majorana and ‹m › >0. n W- eep
0 2 decay If mediated by the exchange of massive Majorana neutrinos: 0νββ Decay rate 1/ = G(Q, Z) |Mnucl|2 <m >2 Phase space Nuclear (~Q 5) matrix element (NME) |Si Uei 2 mi | Majorana neutrino mass Experimental signatures: • peak at Q = Ee 1 + Ee 2 - 2 me • two electrons from vertex • production of grand-daughter isotope • 2 background (resolution) • nuclear backgrounds
Double Beta Decay Candidates
Neutrinoless Double Beta Decay LNGS program: complementary approaches concerning isotopes and techniques Ø GERDA: HPGe detectors enriched in 76 Ge § running Ø CUORE: Te. O 2 bolometers (130 Te) § construction phase. Ø Lucifer R&D to further suppress background: scintillating bolometers Ø COBRA R&D: Cd. Zn. Te room temperature detectors
GERDA INAUGURATION CERIMONY LNGS November 9 2010
The GERDA concept Use cryogenic liquid (liquid argon) as cooling medium and shield simultaneously array of naked detectors G. Heusser, Ann. Rev. Nucl. Part. Sci. 45 (1995) 543 Clean room Lock system Detector array Cryostat with internal Cu shield Water tank with HP water and -veto HP liquid Ar Additional water shielding: - cheap and safe - neutron moderator - Cherenkov medium for 4 p muon veto LAr required to shield g radiation from the stainless steel cryostat and from the rock external background from g, m and n < 10 -4 counts/(ke. V·kg·y)
GERDA goals and sensitivity GERDA goal: 10 -3 counts/(ke. V kg y) improvement of a factor 100 with respect of H-M Phase I: test claim crystals from HM and IGEX phase II phase I exposure: 15 kg·y bck: 10 -2 counts/(ke. V kg y) Phase II: measure T 1/2 or improve limit claim new better enr. Ge detectors (bought 40 kg of raw material) exposure: 100 kg·y bck: 10 -3 counts/(ke. V kg y)
Enriched detectors in GERDA Three enr. Ge detectors installed in May 2011 § ANG 4, RG 1 & 2 installed inside a new mini-shroud (unexpected 42 Ar/42 K signal) § The leakage currents for detectors < 50 p. A § Commissioning with enr. Ge detectors to confirm background at Q , ca. 4· 10 -2 counts/(ke. V·kg·y) All eight enr. Ge detectors (+ three November 2011 nat. Ge) deployed in § GERDA Phase I officially started! § Stable data taking since then § Background further improved (~factor of 2) § 42 K line a factor of 15 smaller than Run 1
Phase I data taking § The experiment is in stable data taking since Nov 6 th (duty cycle > 95%) § Exposure collected up to now with enr. Ge detectors > 4 kg·y § 30% of the nominal Phase I exposure (15 kg·y), about ½ of the exposure of the IGEX experiment § Blinding is applied to events in the Q region (from 2019 to 2059 ke. V) § the box will be opened when the nominal Phase I exposure is achieved § Studies are ongoing to assess the background contributions from U/Th chains, 42 K, a and m § only a few lines clearly seen in spite of the large exposure good! § study the 2 -neutrino decay with enr. Ge detectors
CUORE (Cryogenic Underground Observatory for Rare Events) The aim of CUORE experiment is is to study 0 from 130 Te by using cryogenic detectors made of Te. O 2 crystals The prototype CUORICINO, operated at LNGS up to 2008, demonstrated the feasibility of the large scale detector CUORE In Construction at LNGS
From CUORICINO to CUORE Closely packed array of 988 detectors 19 towers - 13 modules/tower - 4 detectors/module M = 741 kg 1027 nuclides 200 kg 130 Te Compact structure, ideal for active shielding Huge thermal detector array in a extremely low radioactivity and low 130 Te vibrations environment Energy resolution: 5 ke. V @ 2615 ke. V (FWHM) Each tower is a CUORICINO-like detector Custom dilution refrigerator
Mass: from few kg to almost a ton The production of CUORE crystals started at SICCAS Jiading in 2008 ~ 30 crystals/month 830 crystals already @ LNGS expected end of delivery in 2012 NUPECC 9 March 2012 33
CUORE goal Background goal: 0. 01 c/ke. V/kg/y T 1/2 = 1. 6 x 1026 y NUPECC 9 March 2012 mββ = 41 -95 me. V Cuoricino result and CUORE 1σ background-fluctuation sensitivity overlaid on plots that show the bands preferred by neutrino oscillation data (inner region: best-fit data; outer region: at 3σ). Both normal (red) and inverted (green) hierarchies are shown. 34
CUORE present status LNGS installation (building and clean room) completed CUORE cryostat commissioning is foreseen in early 2012 More than 800 crystals already @ LNGS. Delivery completed in 2012 Gluing & Assembly lines commissioned and tested Custom dilution refrigerator ordered to Leiden Cryogenics better than specifications The CUORE-0 prototype will be installed in few weeks in the Cuoricino cryostat CUORE data taking foreseen in 2014 NUPECC 9 March 2012 35
Conclusions Ø INFN-Gran Sasso laboratory is the largest underground laboratory in the world § Leadership in massive experiments with record performance and low-level background Ø The present scientific program of LNGS includes a very broad spectrum of competitive experiments (astroparticle, particle and nuclear physics) § 16 experiments + R&D activities, including world-leading in the fields of solar neutrinos, accelerator neutrinos, double beta decay, dark matter and nuclear astrophysics Ø Plan to maintain the scientific excellence in the next years by an extensive physics program (new experiments and upgrades of the present ones) Ø After the end of the CNGS program (2013 -2015), underground space (OPERA and ICARUS) could be made available § laboratory still open to proposals for new and innovative experiments
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