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Hmotná neutrina Vít Vorobel, ÚČJF MFF UK
Úvod (milníky, pojmy) Kinematická měření mn Oscilace neutrin (mixování neutrin) Dvojný beta-rozpad (Majorana x Dirac ?) Experiment NEMO-3 – dvojný beta-rozpad Experiment SuperNEMO Experiment Daya Bay – oscilace reaktorových antineutrin Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Neutrinové milníky 1930 Pauli – neutrální částice v b-rozpadu 1937 Majorana – co když n = anti-n ? 1956 Reines, Cowan – pozorování reaktorových anti-n 1957 Pontecorvo – hypotéza oscilací neutrin 1968 Davis – pozorování slunečních n (deficit) množství experimentů a trpělivost 1998 Super-Kamiokande – pozorování oscilací atmosférických n 80 let poté 2010 Hierarchie? Majorana? Hmotnost? Proč tak malá? ... Seminář ÚČJF - Vít Vorobel
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Základní formalizmus - mísení neutrin
Slabé stavy Hmotnostní stavy Směšovací matice Pontecorvo-Maki-Nakagawa-Sakata Informace o hmotnosti neutrin (9 parametrů) Hmotnosti (3) Parametry PMNS matice Směšovací úhly (3) Diracova fáze (1) Majoranovy fáze (2) Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Kinematická měření Beta – rozpad 3H Mainz, Troick, mne < 2 eV/c2 KATRINE, plánovaná citlivost 0.2 eV/c2 Rozpad p – PSI, mnm < 170 keV/c2 Rozpad t – OPAL, DELPHI,ALEPH mnt < 18 MeV/c2 Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Oscilace neutrin Oscilace ve vakuu - Pontecorvo 1957 2 neutrina: oscilační délka Oscilace v hmotném prostředí - Wolfenstein 1978, Mikheyev-Smirnov (MSW effect) významný efekt pro sluneční a urychlovačová neutrina Z0 : ne, nm, nt W+: pouze ne Efektivní mi jsou jiná v prostředí než ve vakuu Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
bb-rozpad (A,Z)(A,Z+2) + 2e- + 2n (A,Z)(A,Z+2) + 2e- 2: proces dovolený v SM, T1/2 ~ 1020y 0: proces mimo SM, T1/2 1025y Seminář ÚČJF - Vít Vorobel
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NEMO-3/SuperNEMO collaboration
Neutrino Ettore Majorana Observatory (Neutrino Experiment on MOlybdenum – historical name) 80 physicists / 30 institutions Seminář ÚČJF - Vít Vorobel
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0nbb and neutrino fundamental properties
Probe of neutrino nature. Neutrinos are Majorana fermions (particle antiparticle) if 0 takes place See-Saw mechanism, Leptogenesis, Baryon asymmetry, CP violation Neutrino mass hierarchy. 0 measurements might help to establish the right one. Absolute mass scale. 0 experiments are among the most sensitive ones. Spreads are due to variations of unknown CP phases Seminář ÚČJF - Vít Vorobel
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Fréjus Underground Laboratory : 4800 m.w.e.
The NEMO3 detector 3 m 4 m B (25 G) Fréjus Underground Laboratory : 4800 m.w.e. 20 sectors Magnetic field: 25 Gauss Gamma shield: Pure Iron (18 cm) Neutron shield: borated water (~30 cm) + Wood (Top/Bottom/Gaps between water tanks) Able to identify e-, e+, g and a-delayed Source: 10 kg of isotopes cylindrical, S = 20 m2, 60 mg/cm2 Tracking detector: drift wire chamber operating in Geiger mode (6180 cells) Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
NEMO3 unique features Multisource bb-detector Multi-source detector Measurement of full bb-event pattern Self-determination of ALL background components measuring independent channels Seminář ÚČJF - Vít Vorobel
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Unique spectra from tracko-calo technique
100Mo 2 Results NEMO-3 ’’2n-factory’’ in action Sum energy spectrum Angular distribution Single electron energy spectrum • Data MC ββ2 background subtracted 100Mo 100Mo 100Mo events 389 days S/B=40 Unique spectra from tracko-calo technique Latest results: Seminář ÚČJF - Vít Vorobel
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(7.11 ± 0.02(stat)±0.54(syst))·1018 (SSD favored)
100Mo 2 Results Summary of NEMO-3 2n-results Isotope Expo- sure, days Events S/B T1/2(2νββ), years Published 100Mo 389 219000 40 (7.11 ± 0.02(stat)±0.54(syst))·1018 (SSD favored) 100Mo(0+1) 334.3 37,5 4 ( (stat) )±0.8(syst))·1020 82Se 2750 (9.6± 0.3(stat)±1.0(syst))·1019 116Cd 168.4 1371 7.5 (2.8± 0.1(stat)±0.3(syst))·1019 150Nd 939 2018 2.8 ( (stat)±0.63(syst))·1018 New preliminary 130Te 1152 236 0.35 (6.9± 0.9(stat)±1.0(syst))·1020 96Zr 1221 428 1 (2.35± 0.14(stat)±0.16(syst))·1019 48Ca 943.2 116 6.8 ( (stat)±0.4(syst))·1019 Systematic studies of 2nbb process provide crucial knowledge for 0nbb search!
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100Mo 2 Results 0n-results Isotope <mn>, eV Experiment Year
T1/2(0νββ) limit, ×1024years <mn>, eV Experiment Year 76Ge > 15.7 < IGEX 2002 15. HM(KGC) 2004 > 15.5 HM(Others) 2005 130Te >3 < CUORICINO 2008 100Mo >1.1 < NEMO-3 2009
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Energy resolution (FWHM) SUPERNEMO R&D is in progress since 2006
From NEMO to SuperNEMO NEMO-3 successful experience allows to extrapolate tracko-calo technique on larger mass next generation detector to reach new sensitivity level. NEMO-3 SuperNEMO 100Mo, 7kg Isotope, mass 82Se, kg 208Tl: < 20 mBq/kg 214Bi: < 300 mBq/kg Background in bb-foil 208Tl: < 2 mBq/kg 214Bi: < 10 mBq/kg 8% Efficiency 30% 3 MeV Energy resolution (FWHM) 3 MeV T1/2 > 2 x 1024 y <mn> < 0.3 – 0.8 eV Sensitivity T1/2 > 1-2 x 1026 y <mn> < 40 – 100 meV SUPERNEMO R&D is in progress since 2006
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SuperNEMO basic design
SuperNEMO module 20 modules, each of them hosts: - 5 kg of source foil (82Se, 40mg/cm2) Geiger channels - 600 Calorimeter channels: PVT Scintillator + 8’’ PMT SuperNEMO is the favorite project to be hosted in the new LSM laboratory (hall A) planned to be opened at 2013
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SuperNEMO demonstrator
Source: 6.3 kg of 82Se Tracker R&D Calorimeter R&D Simulations Low background R&D BiPo setup SuperNEMO demonstrator (first module) being finalizing, which will: Prove the concept Test 0nbb at level of KGC Start in 2012
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Aktivity MFF UK v NEMO-3/SuperNEMO
V úzké spolupráci s UTEF ČVUT NEMO-3 Simulace a návrh neutronového stínění Koordinace výroby/dodávky nosné konstrukce detektoru (Transporta Chrudim) Koordinace výroby/dodávky „Radon Trapping Facility“ (Hradec Králové) Analýza dat 150Nd (excitovaný stav) SuperNEMO Studie alternativní podoby kalorimetru (PD x PMT) Optimalizace tvaru scintilátorů Měření Rn Testování scintilátorů BiPo setup Seminář ÚČJF - Vít Vorobel
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Scintillator response vs irradiation position
position scan Peak position, ADC Irradiated area 11.6 mm 1 MeV, % 91.5 88.6 85.5 20 mm 20 mm 11.8 13.8 14.1 87.3 88.7 91.9 12.7 11.5 13.9 90.6 92.5 89.9 13.7 11.9 12.5 NEMO3/SuperNEMO collaboration meeting, Prague
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Daya Bay Reactor Antineutrino Oscillation Experiment
Seminář ÚČJF - Vít Vorobel
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The Daya Bay Collaboration
North America (14)(54) BNL, Caltech, George Mason Univ., LBNL, Iowa state Univ. Illinois Inst. Tech., Princeton, RPI, UC-Berkeley, UCLA, Univ. of Houston, Univ. of Wisconsin, Virginia Tech., Univ. of Illinois-Urbana-Champaign Asia (18) (88) IHEP, Beijing Normal Univ., Chengdu Univ. of Sci. and Tech., CGNPG, CIAE, Dongguan Polytech. Univ., Nanjing Univ.,Nankai Univ., Shandong Univ., Shenzhen Univ., Tsinghua Univ., USTC, Zhongshan Univ., Hong Kong Univ., Chinese Hong Kong Univ., National Taiwan Univ., National Chiao Tung Univ., National United Univ. Europe (3) (9) JINR, Dubna, Russia Kurchatov Institute, Russia Charles University, Czech Republic ~ 150 collaborators Seminář ÚČJF - Vít Vorobel
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13The Last Unknown Neutrino Mixing Angle
? UMNSP Matrix Maki, Nakagawa, Sakata, Pontecorvo atmospheric, accelerator reactor, 0 SNO, solar SK, KamLAND 12 ~ 32° 23 = ~ 45° 13 = ? ? What ise fraction of 3? Ue3 is the gateway to CP violation in neutrino sector: 23 45 P( e) - P( e) sin(212)sin(223)cos2(13)sin(213)sin ˉ Seminář ÚČJF - Vít Vorobel
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Small oscillation due to q13 Large oscillation due to q12
Measuring 13 Using Reactor Anti-neutrinos Electron anti-neutrino disappearance probability Small oscillation due to q13 < 2 km Large oscillation due to q12 > 50 km Osc. prob. (integrated over En ) vs distance e disappearance at short baseline(~2 km): unambiguous measurement of 13 Sin22q13 = 0.1 Dm231 = 2.5 x 10-3 eV2 Sin22q12 = 0.825 Dm221 = 8.2 x 10-5 eV2 Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
4 x 20 tons target mass at far site Daya Bay: Powerful reactor close to mountains Far site 1615 m from Ling Ao 1985 m from Daya Overburden: 350 m 900 m Ling Ao Near site ~500 m from Ling Ao Overburden: 112 m Mid site 873 m from Ling Ao 1156 m from Daya Overburden: 208 m Ling Ao-ll NPP (under construction) 22.9 GW in 2011 465 m Construction tunnel 810 m Ling Ao NPP, 22.9 GW Filling hall entrance Daya Bay Near site 363 m from Daya Bay Overburden: 98 m 295 m Daya Bay NPP, 22.9 GW Total length: ~3100 m Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Detection of e Inverse -decay in Gd-doped liquid scintillator: + p D + (2.2 MeV) (t~180μs) 0.3b + Gd Gd* Gd + ’s(8 MeV) (t~30μs) 50,000b Time, space and energy-tagged signal suppress background events. E Te+ + Tn + (mn - mp) + m e+ Te MeV Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Antineutrino Detector Cylindrical 3-Zone Structure separated by acrylic vessels: I. Target: 0.1% Gd-loaded liquid scintillator, diameter=height= 3.1 m, 20 ton II. g-catcher: liquid scintillator, 42.5 cm thick III. Buffer shielding: mineral oil, cm thick With 192 PMT’s on circumference and reflective reflectors on top and bottom: 12.2% 13cm Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Inverse-beta Signals Antineutrino Interaction Rate (events/day per 20 ton module) Daya Bay near site 840 Ling Ao near site 740 Far site Ee+(“prompt”) [1,8] MeV En-cap (“delayed”) [6,10] MeV tdelayed-tprompt [0.3,200] s Delayed Energy Signal Prompt Energy Signal MC statistics corresponds to a data taking with a single module at far site in 3 years. 1 MeV 8 MeV 6 MeV 10 MeV Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Muon “Veto” System Resistive plate chamber (RPC) Surround detectors with at least 2.5m of water, which shields the external radioactivity and cosmogenic background Water shield is divided into two optically separated regions (with reflective divider, 8” PMTs mounted at the zone boundaries), which serves as two active and independent muon tagger Augmented with a top muon tracker: RPCs Combined efficiency of tracker > 99.5% with error measured to better than 0.25% Outer water shield Inner water shield Seminář ÚČJF - Vít Vorobel
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Seminář ÚČJF - Vít Vorobel
Backgrounds Background = “prompt”+”delayed” signals that fake inverse-beta events Three main contributors, all can be measured: Background type Experimental Handle Muon-induced fast neutrons (prompt recoil, delayed capture) from water or rock >99.5% parent “water” muons tagged ~1/3 parent “rock” muons tagged 9Li/8He (T1/2= 178 msec, b decay w/neutron emission, delayed capture) Tag parent “showing” muons Accidental prompt and delay coincidences Single rates accurately measured Background/Signal: DYB site LA site Far site Fast n / signal 0.1% 9Li-8He / signal 0.3% 0.2% Accidental/signal <0.2% <0.1% Seminář ÚČJF - Vít Vorobel
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Daya Bay: Status and Plan
Ground Breaking Oct 07 CD-3 review comleted Spring 08 Surface Assembly Building occupancy March 09 Mini Dry Run Dec 09 Dry Run Spring 09 Daya Bay Near Hall ready for data taking All near and far halls ready for data taking Run Time (Years) sin2213 0.01 Goal: sin2213 (90% C.L.) Seminář ÚČJF - Vít Vorobel
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Testování RPC kosmickým zářením – IHEP Peking
Kritéria testů: účinnost >95% singles (šum)< 0.8Hz/cm dark current< 10 μA/m2 Testováno 1600 ks RPC, odmítnuto 15% Seminář ÚČJF - Vít Vorobel
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谢谢你们 ！ Děkuji za pozornost !
Seminář ÚČJF - Vít Vorobel
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