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zone convective 2e - +4p 4 He+2 e MeV coeur zone radiative 500'000 km (70% 1 H, 28% 4 He,...) e L=1.44 10 11 m. Le soleil
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10 0 10 -2 10 1 10 -1 10 -3 10 7 10 6 10 5 10 4 r[R ] g cm -3 ] T[K] 10 2 10 8 T=10 7 K: plasma with Tcin 0.8 keV, enough for penetration through Coulomb barrier via tunnel effect, nuclear reactions
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8 B 8 Be+e + + e +14.6 MeV 3 He+ 3 He 4 He+2p+12.86 MeV p+p 2 H+e + + e +0.42 MeV 0.25 % 99.75 % 2 H+p 3 He+ +5.49 MeV 3 He+ 4 He 7 Be+ +1.59 MeV 86 % 14 % Q=26.2 MeV p+e - +p 2 H+ e +1.44 MeV 7 Be+e - 7 Li+ e +0.87 MeV 7 Be+p 8 B+ +0.14 MeV 99.89 % 0.11 % 7 Li+p 4 He+ 4 He+17.35 MeV Q=25.7 MeV 8 Be 4 He+ 4 He+3 MeV Cycle pp (98.5 % de la luminosité)
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12 C+p 13 N+ 13 N 13 C+e + + e (1.2 MeV) 13 C+p 14 N+ 14 N+p 15 O+ 15 O 15 N+ e + + e (1.73 MeV) 15 N+p 12 C+ 4 He Cycle CNO (1.5 % soleil)
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SNO
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CC interaction sensitive only to e. Proposed by Pontecorvo in 1946. N* is extracted from the target with physical-chemical techniques and identified by its decay back in N. 1 Solar Neutrino Unit [SNU] = 1 interaction/sec each 10 36 target atoms. Radiochemical experiments
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37 Cl( e,e) 37 Ar (Ethr = 813 keV) Kshell EC t = 50.5 d 37 Cl + 2.82 keV (Auger e -, X) 615 t C 2 Cl 4 tank, in Homestake mine (4400 mwe) 37 Cl atoms (nat abundance 24 %) Every 30 days inject 0.2 cc Ar, purge with He to remove 37 Ar, fill prop. counter pep0.2 SNU 7Be1.2 SNU 8B6.2 SNU CNO 0.4 SNU Tot calc.8.1 ± 1.8 Measured3.23 SNU ± 0.68 (0.46-0.08=0.38 atom/day) cosmic background Bahcall and Pinsonnault +SSM
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Gallex-GNO Gran Sasso lab (3500 mwe) 30 t of Ga (40 % 71 Ga) GeH 4 E th =0.233 MeV
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Calibration with 51 Cr source
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day -1 SNU pp0.6170.8 pep0.02 3.0 7 Be0.3034.3 8 B0.1014.0 CNO0.08 9.9 tot1.14132 tot0.61 70.8 4 tot 66.9 5 BP+SSM Gallex-GNO measured SAGE (metallic Ga) Deficit of solar neutrinos
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Superkamiokande (Japon) : 50 kt H 2 O photomultiplicateurs
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1000 tonnes D 2 O 12 m diameter Acrylic Vessel 18 m diameter support structure; 9500 PMTs (~60% photocathode coverage) 1700 tonnes inner shielding H 2 O 5300 tonnes outer shielding H 2 O Urylon liner radon seal depth: 2092 m (~6010 m.w.e.) ~70 muons/day Sudbury Neutrino Observatory
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SNO, construction of acrylic vessel Acrylic vessel+PMT Water purification system Photos courtesy of SNO
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Neutrino Reactions in SNO - Q = 1.445 MeV - good measurement of e energy spectrum - some directional info (1 – 1/3 cos ) - e only - Q = 2.22 MeV - measures total 8 B flux from the Sun - equal cross section for all active flavors NC xx npd ES e−e− e−e− x - low statistics - mainly sensitive to e, some and - strong directional sensitivity CC e−e− ppd e x
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Čerenkov Detection PMT Measurements -position -charge -time Reconstructed Event -event vertex -event direction -energy-isotropy
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SNO Neutral Current Trilogy Pure D 2 O Nov 99 – May 01 n d t (E = 6.25 MeV) good CC PRL 87, 071301 (2001) PRL 89, 011301 (2002) PRL 89, 011302 (2002) “D 2 O Archival Long Paper” in progress Salt Jul 01 – Sep 03 n 35 Cl 36 Cl (E = 8.6 MeV) enhanced NC and event isotropy PRL 92, 181301 (2004) “Long Salt Paper” soon to be submitted 3 He Counters Fall 04 – Dec 06 n 3 He t p proportional counters = 5330 b event-by-event separation “First NCD Paper” in the future
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Physics Motivation Event-by-event separation. Measure NC and CC in separate data streams. Different systematic uncertainties than neutron capture on NaCl. 3 He array removes neutrons from CC, calibrates remainder. CC spectral shape. Detection Principle 2 H + x p + n + x - 2.22 MeV (NC) 3 He + n p + 3 H + 0.76 MeV 40 Strings on 1-m grid 398 m total active length x n NCD PMT SNO Phase III: 3 He Detectors 3 He Proportional Counters (“NC Detectors”)
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391 days salt phase
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Favored channel:
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N= 235 U, 238 U, 239 Pu, 241 Pu
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600 K (PWR) A Fragment distribution
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PWR: 238 U+3.5 % 235 U (start) n th + 239 Pu, 241 Pu n fast + 238 U
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e e ( disappearance experiment) P th = 8.4 GW th, L = 1.050 km, M = 5 t overburden: 300 mwe CHOOZ
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Prompt e+, E P =1-8 MeV, visible energy Delayed neutron capture on Gd, E D =8 MeV Prompt( / ) - Delayed( / ) some pulse shape discrimination information Directionality: weak & statistical (to be studied for the future) Time correlation: 30 sec Space correlation: < 1m 3 prompt event: Q~1.8 MeV Threshold 0.7-9 MeV delayed event: 6-11 MeV CHOOZ
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Gd loaded scintillator (0.1 %)
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CHOOZ
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KAMLAND
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Chooz: 13 <13 0
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solar Kamland Kamland + solar
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solar: Cl37+Gallex+SAGE+SK+SNO reactor: Kamland allowed area (95 % CL) SK: day-night assymetry measured:
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SK atmospheric neutrinos Expected Best fit
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Favored channel:
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Provide an unambiguous evidence for oscillations in the region of atmospheric neutrinos by looking for appearance in a pure beam Search for the subleading e oscillations (measurement of 13 ) 732 Km Given the distance (732 Km): flux optimized for the maximal number of charged current interactions = 43 Km/GeV : « off peak » 17 GeV ( e + e )/ 0.87% / 2.1% promptnegligible CNGS PROGRAM: OPERA: 6200 CC+NC /year 19 CC/year (@ 2 10 -3 eV 2 )
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8.3kg 10 X0 Pb Emulsion layers 1 mm The basic unit: the « Brick » Based on the concept of the Emulsion Cloud Chamber (ECC) 56 Pb sheets 1mm + 56 emulsion layers Solves the problem of compatibility of large mass for neutrino interactions + high space resolution in a completely modular scheme ECC are completely stand-alone detectors: Neutrino interaction vertex and kink topology reconstruction Measurement of the momenta of hadrons by multiple scattering dE/dx pion/muon separation at low energy Electron identification and measurement of the energy of the electrons and photons 10.2 x 12.7 x 7.5 cm ECC Tecnique validated by the direct observation of : DONUT 2000
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supermodule 8 m Target Trackers Pb/Em. target ECC emulsions analysis: Vertex, decay kink e/ ID, multiple scattering, kinematics Extract selected brick Pb/Em. brick 8 cm Pb 1 mm Basic “cell” Emulsion trigger and localization of neutrino interactions muon identification and momentum/charge measurement need for a hybrid detector Electronic detectors: Brick finding,muon ID, charge and p Link to mu ID, Candidate event Use of the electronic detectors: Spectrometer
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Target Tracker XY planes, 7000m 2 in total 32256 Scintillator strips 6.86m x 2.6cm x1cm AMCRYS-H (Kharkov) + Kuraray WLS 1000 MaPMT Hamamatsu 64channels Dedicated Front End electronics for gain correction Autotriggerable and threshold @ 1/5 p.e Ethernet DAQ cards Well above 5 p.e. / readout end (in the middle: worst case for two-end readout) 6.9m Construction of the modules in progress (8/week) Installation at LNGS since September 2004 1.7 m 0 max p.h. Neutrino interaction trigger Brick localization Muon tracking and ID 64 strips/module
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OPERA structure with two Super-Modules 31 target planes / supermodule (in total: 206336 bricks, 1766 tons) Targets Magnetic Spectrometers Proposal: July 2000, installation at LNGS started in May 2003 SM1SM2
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Data taking starts in 2006, prepare scanning!
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sensitivity full mixing, 5 years run @ 4.5 x10 19 pot / year signal ( m 2 = 1.9 x 10 -3 eV 2 ) signal ( m 2 = 2.4 x 10 -3 eV 2 ) signal ( m 2 = 3.0x 10 -3 eV 2 ) BKGD OPERA 1.8 kton fiducial 6.6(10)10.5(15.8)16.4(24.6)0.7(1.06 ) (…) with CNGS beam upgrade (X 1.5) m 2 (10 -2 eV 2 ) Probability of observing in 5 years a number of candidates greater than a 4 background fluctuation
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13, or U e3 = Y. Giomataris and J.D. Vergados Xenon(?) at 1 bar R determined from lateral diffusion 3 H 3 He+ e +e - (Q=18.6 keV) 6x10 18 /s T max =1.27 keV E th =200 eV
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Neutrino energy (T>200 eV) R(m) m 2 =2.5x10 -3 eV 2 =0.17
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