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The MAJORANA DEMONSTRATOR a Search for Neutrinoless Double-Beta Decay of Germanium-76

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The MAJORANA DEMONSTRATOR a Search for Neutrinoless Double-Beta Decay of Germanium-76 Office of Nuclear Physics MAJORANA The MAJORANA DEMONSTRATOR A search for neutrinoless double-beta decay of germanium-76 Alexis Schubert on behalf of the MAJORANA Collaboration Center for Experimental Nuclear Physics and Astrophysics The MAJORANA Collaboration (June 2011) Note: Red text indicates students The MAJORANA Collaboration MAJORANA Pacific Northwest National Laboratory, Richland, Washington Black Hills State University, Spearfish, SD Craig Aalseth, Estanislao Aguayo, Jim Fast, Eric Hoppe, Kara Keeter Todd Hossbach, Marty Keillor, Jeremy Kephart, Richard T. Kouzes, Harry Miley, John Orrell, Doug Reid Duke University, Durham, North Carolina , and TUNL Matthew Busch, James Esterline, Gary Swift, Werner Tornow Queen's University, Kingston, Ontario Art McDonald Institute for Theoretical and Experimental Physics, Moscow, Russia Alexander Barabash, Sergey Konovalov, South Dakota School of Mines and Technology, Rapid City, South Dakota Igor Vanushin, Vladimir Yumatov Cabot-Ann Christofferson, Mark Horton, Stanley Howard Joint Institute for Nuclear Research, Dubna, Russia University of Alberta, Edmonton, Alberta Viktor Brudanin, Slava Egorov, K. Gusey, Aksel Hallin Oleg Kochetov, M. Shirchenko, V. Timkin, E. Yakushev University of Chicago, Chicago, Illinois Lawrence Berkeley National Laboratory, Berkeley, California and Juan Collar, Nicole Fields the University of California - Berkeley Mark Amman, Marc Bergevin, Yuen-Dat Chan, Jason Detwiler, University of North Carolina, Chapel Hill, North Carolina and TUNL James Loach, Paul Luke, Ryan Martin, Alan Poon, Gersende Prior, Padraic Finnerty, Florian Fraenkle, Graham Giovanetti, Matthew Green, Kai Vetter, Harold Yaver Reyco Henning, Mark Howe, Sean MacMullin, David G. Phillips II, Jacqueline Strain, Kris Vorren, John F. Wilkerson Los Alamos National Laboratory, Los Alamos, New Mexico Melissa Boswell, Steven Elliott, Victor M. Gehman, University of South Carolina, Columbia, South Carolina Andrew Hime, Mary Kidd, Ben LaRoque, Keith Rielage, Larry Frank Avignone, Leila Mizouni Rodriguez, Michael Ronquest, Harry Salazar, David Steele University of South Dakota, Vermillion, South Dakota North Carolina State University, Raleigh, North Carolina and TUNL Vince Guiseppe, Tina Keller, Keenan Thomas, Dongming Mei, Dustin Combs, Lance Leviner, Albert Young Gopakumar Perumpilly, Chao Zhang Oak Ridge National Laboratory, Oak Ridge, Tennessee University of Tennessee, Knoxville, Tennessee Fred Bertrand, Greg Capps, Ren Cooper, Kim Jeskie, Yuri Efremenko, Sergey Vasiliev David Radford, Robert Varner, Chang-Hong Yu University of Washington, Seattle, Washington Osaka University, Osaka, Japan Tom Burritt, Jonathan Diaz, Peter J. Doe, Greg Harper, Robert Johnson, Hiroyasu Ejiri, Ryuta Hazama, Masaharu Nomachi, Shima Tatsuji Andreas Knecht, Michael Marino, Mike Miller, David Peterson R. G. Hamish Robertson, Alexis Schubert, Tim Van Wechel, Brett Wolfe The MAJORANA DEMONSTRATOR PANIC11 Neutrinoless double-beta decay (0νββ) MAJORANA • Observation indicates: Neutrino is a Majorana particle • • Lepton number is not conserved summed electron energy • Measurement of rate could provide information about neutrino mass 2νββ counts 0νββ Q-value The MAJORANA DEMONSTRATOR 3 PANIC11 Neutrino mass and 0νββ MAJORANA Sensitivity of a tonne-scale 76Ge experiment 0νββ rate (T1/2)-1 = G0ν M0ν 2 mββ2 Double-Beta Decay andNeutrino Neutrino mass hierarchy Mass m3 m2 m1 Normal $mAtm%45 meV Hierarchy Inverted Hierarchy !e !" !# NME: Simkovic et al, Phys Ref C 79, 055501 (2009) m2 m3 $mSol%9 meV m1 iδ i α1 c12c13 s12c13 s13e− e 2 00 iδ iδ i α2 U = s12c23 c12s23s13e c12c23 s12s23s13e s23c13 0 e 2 0 − − iδ − iδ s12s23 c12c23s13e c12s23 s12c23s13e c23c13 0 0 1 − − − 2 mββ = Ueiξimi ! " ! ! ! i ! The MAJORANA D!EMONSTRATOR" ! 4 PANIC11 ! ! 0!&& is sensitive to! !m&&", !and therefore the absolute masses, mixings and CP phases The GERDA and MAJORANA Experiments MAJORANA MAJORANA Detector array: enriched Ge crystals Detector array: enriched Ge crystals in submerged in liquid argon vacuum cryostats Shield: high-purity liquid argon, H20 Shield: lead, copper http://www.mpi-hd.mpg.de/gerda http://majorana.npl.washington.edu Goal: select best techniques developed in GERDA and MAJORANA for a joint tonne-scale Ge experiment The MAJORANA DEMONSTRATOR 5 PANIC11 The GERDA and MAJORANA Experiments MAJORANA MAJORANA 14:30 4-163 Status and Perspective of the GERDA Neutrinoless Double Beta Decay Experiment Karl Tasso Knoepfle Detector array: enriched Ge crystals Detector array: enriched Ge crystals in submerged in liquid argon vacuum cryostats Shield: high-purity liquid argon, H20 Shield: lead, copper http://www.mpi-hd.mpg.de/gerda http://majorana.npl.washington.edu Goal: select best techniques developed in GERDA and MAJORANA for a joint tonne-scale Ge experiment The MAJORANA DEMONSTRATOR 5 PANIC11 The MAJORANA Experiment MAJORANA • Search for neutrinoless double-beta decay using an array of germanium detectors enriched in 76Ge • First phase of MAJORANA under construction: the DEMONSTRATOR, 40-kg R&D detector • Attempt to achieve a background rate 100x lower than previous Ge experiments The MAJORANA DEMONSTRATOR 6 PANIC11 The MAJORANA Experiment MAJORANA • Search for neutrinoless double-beta decay using an array of germanium detectors enriched in 76Ge • First phase of MAJORANA under construction: the DEMONSTRATOR, 40-kg R&D detector • Attempt to achieve a background rate 100x lower than previous Ge experiments Background goal for tonne-scale: 1 count per tonne-year in 4-keV region surrounding Q-value The MAJORANA DEMONSTRATOR 6 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA • First phase of the MAJORANA experiment • 40-kg ultra-clean Ge detector array deployed in two cryostats at 4850ʼ level of Sanford Lab • 20 to 30 kg of crystals enriched to 86% 76Ge • Technical goal: demonstrate background levels that justify construction of tonne-scale experiment • Science goal: test recent claim of 0νββ observation - Phys. Lett. B 586 198 (2004) the inside of The MAJORANA DEMONSTRATOR 7 a cryostat PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Ge detector detector string cryostat TheThe M DAJORANAEMONSTRATOR DEMONSTRATOR 8 PANIC11 The MAJORANA DEMONSTRATOR MAJORANA Passive and active shielding: polyethylene scintillator veto radon exclusion box lead commercial copper electro-formed copper The MAJORANA DEMONSTRATOR 9 PANIC11 Germanium detectors MAJORANA • MAJORANA will use p-type point contact Ge detectors • Excellent energy resolution: 0.16% FWHM at 2039 keV Q-value • Can be enriched to 86% in 76Ge: source is detector • Pulse-shape analysis can distinguish multi-site backgrounds from single-site signal events • Low energy threshold allows opportunistic physics: dark matter search energy spectrum with pulse-shape analysis model of electric field in PPC detectors 30 1 25 0.8 208 20 Tl all events 0.6 15 DEP single-site events Z (mm) 0.4 10 0.2 5 0 0 -30 -20 -10 0 10 20 30 Radius (mm) The MAJORANA DEMONSTRATOR 10 PANIC11 Backgrounds MAJORANA The MAJORANA DEMONSTRATOR 11 PANIC11 Backgrounds MAJORANA Intrinsic radiation: U and Th decay chains, 2νββ Cosmic rays: Expected backgrounds • Activation at surface creates unstable isotopes in Ge, copper • Muons, muon-induced neutrons can interact in detectors and apparatus The MAJORANA DEMONSTRATOR 11 PANIC11 Backgrounds MAJORANA Intrinsic radiation: U and Th decay chains, 2νββ Cosmic rays: Expected backgrounds • Activation at surface creates unstable isotopes in Ge, copper • Muons, muon-induced neutrons can interact in detectors and apparatus Background Passive and active shielding: copper, lead, polyethylene, scintillator reduction Ultra-clean materials: Ge, copper, parylene techniques Depth: experiment will be conducted deep underground The MAJORANA DEMONSTRATOR 11 PANIC11 Backgrounds MAJORANA Intrinsic radiation: U and Th decay chains, 2νββ Cosmic rays: Expected backgrounds • Activation at surface creates unstable isotopes in Ge, copper • Muons, muon-induced neutrons can interact in detectors and apparatus Background Passive and active shielding: copper, lead, polyethylene, scintillator reduction Ultra-clean materials: Ge, copper, parylene techniques Depth: experiment will be conducted deep underground Analysis cuts: 0νββ should deposit energy in a small region of a single detector; other events can be flagged: Background mitigation • events that deposit energy in multiple detectors techniques • events that deposit energy in multiple locations in one detector • events that are time correlated with other events The MAJORANA DEMONSTRATOR 11 PANIC11 Recent progress MAJORANA • DOE and NSF funding started in FY 2010 • November 2010: 19 of 36 natural Ge detectors delivered to Sanford Lab • April 2011: All 36 natural Ge detectors characterized and accepted by Los Alamos National Lab • June 2011: Isoflex completed enrichment of 20 kg Ge; delivery by Sept. 2011 • August 2010: Production of electro-formed copper
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