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Astroparticle Physics at Gran Sasso Underground Laboratory: Borexino and geo-neutrino

Astroparticle Physics at Gran Sasso Underground Laboratory: Borexino and geo-neutrino. Lino Miramonti – 7 Feb 2006 - Honolulu (Hawaii). Astroparticle Physics. Astrophysics & Cosmology. Particle physics. Astroparticle physics.

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Astroparticle Physics at Gran Sasso Underground Laboratory: Borexino and geo-neutrino

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  1. Astroparticle Physics at Gran Sasso Underground Laboratory: Borexino and geo-neutrino Lino Miramonti – 7 Feb 2006 - Honolulu (Hawaii) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  2. Astroparticle Physics Astrophysics & Cosmology Particle physics Astroparticle physics • Employs knowledges and techniques from particle physics in order to study cosmological and astrophysical aspects. • Detects particles coming from space for particle physics studies. • Typical studies of astroparticle physics are: • Neutrino Physics(Solar, Supernova, Atmospherics, Geoneutrinos, neutrinos from reactors and from accelerators, etc..) • Cosmic Ray Physics • Rare Processes(double beta decay, proton decay etc..) • Dark Matter (WIMP’s) • Gravitational Waves • Nuclear Physics (Cross section measurements of astrophysics interest) • ……. Very little cross sections and/or very rare processes of events means to locate detector apparatus to the shelter from cosmic radiation Underground Physics Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  3. Underground Laboratories in Europe Pyhäsalmi Boulby Frejus Canfranc Gran Sasso

  4. ILIAS Integrated Large Infrastructures for Astroparticle Science ILIAS is an initiative supported by the European Union with the aim to support the European large infrastructures operating in the astroparticle physics sector. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  5. The ILIAS project is based on 3 groups of activities: • Networking Activities • (N2) Deep Underground science laboratories • (N3) Direct dark matter detection • (N4) Search on double beta decay • (N5) Gravitational wave research • (N6) Theoretical astroparticle physics • Joint Research Activities (R&D Projects) • (JRA1) Low background techniques for Deep Underground Science • (JRA2) Double beta decay European observatory • (JRA3) Study of thermal noise reduction in gravitational wave detectors • Transnational Access Activities • (TA1) Access to the EU Deep Underground Laboratories Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  6. JRA1 (Joint Research Activities 1) Low background techniques for deep underground sciences (LBT-DUSL) • Objectives: • Background identification and measurement (intrinsic, induced, environmental) • Background rejection techniques (shielding, vetoes, discrimination) Working packagesWP1: Measurements of the backgrounds in the underground labsWP2: Implementation of background MC simulation codesWP3: Ultra-low background techniques and facilitiesWP4: Radiopurity of materials and purification techniques A vast R&D programme on the improvement and implementation of ultra-low background techniques will be carried out cooperatively in the 5 European Underground Laboratories. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  7. LNGS - Laboratori Nazionali del Gran Sasso http://www.lngs.infn.it/ Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  8. LNGS permanent staff: 60 (physicists, technicians, administration) Scientists involved in LNGS experiments: 700 from 24 countries Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  9. 3 main halls A B C 100 x 18 m2 (h.20 m) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  10. Backgrounds & Facilities @ LNGS Residual muon flux (6 order of magnitude lower than surface) Coming from spontaneus fission (in particular from 238U) and (α,n) reaction on light elements in the rock also µ-induced neutrons Troublesome for anti-ν detection by Cowan-Reines reaction! Rock of Hall A is 10 times more radioactive in 238U than Hall B and Hall C (and 30 times more radioactive in 232Th) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  11. FACILITY FOR LOW-LEVEL RADIOACTIVITY MEASUREMENTS Present: 32 m2 on one floor in service tunnel Future: 60 m2 distributed on three floors in hall A HPGe Hall (32 m2 floor) Courtesy by Matthias.Laubenstein Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  12. Experiments @ LNGS (Gran Sasso) Completed experiments Atm ν, Monopoles MACRO (Streamer tubes + Liquid scintillators) Solar neutrinos GALLEX / GNO (~ 30 T Gallium radiochemical detector) ββ Heidelberg-Moscow (~ 11 kg enriched 76Ge detectors) Mibeta (~ 7 kg Bolometers TeO2) Dark Matter DAMA (~100 kg NaI detectors) MI-Beta Macro bb H-M Gallex - GNO Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  13. Running experiments ββ Cuoricino (~ 41 kg TeO2 crystals) Dark Matter CRESST (Sapphire cryodetector & CaWO4 crystals (phonons+scintillation)) LIBRA (~ 250 kg NaI crystals) HDMS / Genius-TF (Ge detector 73Ge enriched) Supernova neutrinos LVD (Streamer tubes + Liquid scintillator) Nuclear astrophysics LUNA (Accelerator) LUNA LIBRA HDMS LVD Cuoricino CRESST Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  14. Under construction CERN-GS beam ν OPERA (Emulsion) ICARUS (~ 600 T Liquid Argon) Solar Neutrinos Borexino (~ 300 T Liquid scintillator) Borexino Planned & proposed ββ CUORE (~ 750 kg Te02) GERDA (76Ge) Nuclear astrophysics LUNA-III Gravitational waves LISA R&D Dark matter Liquid Xe / Liquid Ar OPERA ICARUS CNGS Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  15. Borexino CHERENKOV Less than 0.01% of the solar neutrino flux is been measured in real time. RADIOCHEMICAL Integrated in energy and time The main goal of Borexino is the measurement in real time of the low energy component of solar neutrinos. pp cycle Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  16. Borexino Collaboration Italy (INFN & Universiy of Milano and Genova, Perugia Univ., LNGS) USA (Princeton Univ., Virginia Tech.) Russia (RRC KI, JINR, INP MSU, INP St. Petersburg) Germany (Hiedelberg MPI, Munich Technical University) France (College de France) Hungary (Research Institute for Particle & Nuclear Physics) Poland (Institute of Physics, Jaegollian University, Cracow) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  17. BOREXINO: subsystems • Scintillator purification systems: • Water extraction • Vacuum distillation • Silicagel adsorption Borexino detector Storage tanks: 300tons of PC Control room Counting room CTF DI Water plant Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  18. Borexino design Core of the detector: 300 tons of liquid scintillator (PC+PPO)contained in a nylon vessel of 8.5 m diameter. The thickness of nylon is 125 µm. 1st shield: 1000 tons of ultra-pure buffer liquid (pure PC) contained in a stainless steel sphere of 13.7 m diameter (SSS). 2200 photomultiplier tubes pointing towards the center to view the light emitted by the scintillator. 2nd shield: 2400 tons of ultra-pure water contained in a cylindrical dome. 200 photomultiplier tubes mounted on the SSS pointing outwards to detect Cerenkov light emitted in the water by muons. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  19. Eν = 862 keV (monochromatic) ΦSSM = 4.8· 109 ν s-1 cm2 Recoil nuclear energy of the e- Elastic Scattering expected rate (LMA hypothesis) is 35 counts/day in the 250-800 keV energy range Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  20. Status of Borexino The detctor is in this moment in commissioning We expect to start data-taking november 2006 Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  21. Experimental Hall C Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  22. External dome 18 m Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  23. Stainless Steel Sphere (SSS) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  24. PMTs ready to be mounted Clean Room Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  25. Borexino inner detector Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  26. Optical fiber istallation Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  27. Borexino inner detector Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  28. Nylon vessels (Princeton Univ.) Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  29. Nylon vessels installation Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  30. Nylon vessels installation Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  31. Nylon vessels installed and inflated Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  32. Cables installation Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  33. Counting Room Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  34. Cleen Room (on top of the Water Tank) for the insertions of lasers and sources for calibrations. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  35. Cleen Room (on top of the Water Tank) for the insertions of lasers and sources for calibrations. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  36. Counting Test Facility (CTF) CTF is a prototype of Borexino. Its main goal was to verify the capability to reach the very low-levels of contamination needed for Borexino 100 PMTs 4 tons of scintillator 4.5m thickness of water shield Muon-veto detector Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  37. Internal view of CTF Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  38. The CTF as a tool for tuning the apparatus before filling In this moment we use the CTF in order: • To asses the performances of the different BOREXINO sub-systems. • To test the 14C content in the PC • To test the efficiency of the purification methods (Water extraction, Vacuum distillation, Silicagel adsorption) • To test the cleanliness of the apparatus Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  39. Backgrounds we have to fight Natural radioactivity Muon Induced reactions Cosmogenic induced isotopes 14C Air contaminants: 222Rn, 85Kr, 39Ar Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  40. Natural radioactivity Primordial radioactivity: ( about 20 radioisotopes with half-life > Earth life) between them: 238U and 232Th (α and β emitters) 40K (β emitter with end-point = 1.3 MeV) • Selection of materials • Surface treatment to avoid dust and particulate • Purification: • Water extraction, • Vacuum distillation, • Ultra filtration • Nitrogen sparging Hardware • Alpha/Beta Discrimination • Delayed Coincidence Software Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  41. Purification of the Scintillator (with US Skids): • Water extraction: Impurity with high solubility in aqueous phase such as K and heavy metals in U Th chains. • Vacuum distillation: Low volatility components such as metals and dust particles. • Ultra filtration: Particle dust. • Nitrogen stripping: Nobles gases. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  42. alpha/beta discrimination The excitation of the scintillator depends on many factors including the energy loss density – a large dE/dx enhances the slow component of the decay curve The ratio tail over total is expected to be greater for alpha than for electrons An efficiency for alpha identification of ~ 97% at 751 keV with an associated beta misidentification of ~ 2.5%. At low energies (300-600 keV) the alpha I dentification efficiency range from 90 to 97 % with an associated beta misidentification of ~ 10%. Tail/Total charge ratio Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  43. Delayed Coincidence in U238 chain 222Rn α=5.49 MeV 218Po α=6.02 MeV 214Pb 214Bi 214Po α=7.69 MeV T=163 µs 210Pb 210Bi 210Po α=5.30 MeV 210Pb Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  44. Delayed Coincidence in Th232 chain 224Ra α=5.68 MeV 220Rn α=6.29 MeV 216Po α=6.792 MeV T=19.8 m 212Pb 212Bi 212Po α=6.04 MeV α=8.79 MeV T=0.3 µs 208Tl 208Pb Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  45. Muon Induced reactions At LNGS we have 1.1 µ m2 h-1 with a <Eµ> = 320 GeV A muon-veto system (The outer water shielding serves at the same time as water Cerenkov detector for atmospheric muons) reduce this number by a factor 5000-10000 Interacting with 12C of the organic scintillator they give: These elements having a τ > 1 s is not possible to tag them Ultrarelativistic µ can produce n which after been captured by p give a 2.2 MeV γ ray: Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  46. Cosmogenic induced isotopes Theoretical sea-level Cosmic Ray Flux (Latitude New York City ≈ LNGS) During transportation, pseudocumene is exposed to cosmic neutrons. Pseudocumene is produced in Sardinia and the voyage to LNGS take about one day. During transportation cosmic neutrons interact with 12C producing 7Be: Be-7 decays by electron capture to Li-7 and emits (with a 10.52% branching fraction) a 478 keV gamma. This line is a potential background in the Borexino neutrino window. 7Be is efficiently removed by distillation! Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  47. 14C The reactions expected to contribute the most to 14C production in deep underground geological formations are: The 14C content depend on the site of extraction. There is no possibility to eliminate this radionuclide, the only thing we can do, is to test, in CTF, samples of pseudocumene before to transport it to LNGS. Our threshold (at 250 keV) is due to the 14C! Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  48. Regular N2 High Purity N2 LAK (Low Ar/Kr content) N2 Air contaminants: 222Rn, 85Kr, 39Ar N2 Plant To reduce the effect of emanation we used only electroplisched stainless steel, applied orbital weldings. 85Kr β emitter: Emax = 687 keV (Eγ = 514 keV) Half-life: 10.8 years N2 used to sparge scintillator 39Ar βemitter: Emax = 565 keV (no gamma) Half-life: 269 years Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  49. sketch of N2 Plant • Liquid Nitrogen (commercial quality 4.0, i.e. 99,99%) is delivered with a truck and stored on site in three tanks of 6 m³. The tanks can be refilled without interrupting the nitrogen supply. • For Standard Purity N2 the liquid nitrogen is simply evaporated. The gas passes through a heat exchanger to keep it at constant temperature of ca. 15°C. The level of 222Rn is usually in the range of 0.1 – 0.2 mBq/m³ (STP). • For the High Purity N2 the liquid nitrogen passes through a cryogenic adsorption trap ("LTA" = Low Temperature Absorber), filled with 11.5 liters of activated carbon. (We use CarboAct F3/F4, which was found to be very low in 226Ra (less than 0,3 mBq/kg)). For the evaporation we use an electrical evaporator with only low surface. The level of 222Rn is usuallyis below 1 µBq/m³ (STP). The output can be up to 100 m³/h. Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

  50. Water plant Deionization Unit Reverse Osmisis Ultra Filters Nitrogen Stripping Lino Miramonti - 7 February 2006 - Honolulu Hawaii (USA)

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