KamLAND Koji Ishidoshiro (Tohoku University) for KamLAND collaboration The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
KamLAND collaboration University of Hida, Japan 46 scientists 11 institutes, NIKEF Central University North Carolina Washington University of Tennessee University Tohoku Hawaii University Colorado State Berkeley Alabama University of Osaka university Tokyo University of university March 2013
Contents - KamLAND detector - Latest results - Next challenges - Summary Note: KamLAND-Zen will be presented in after noon session and poser session.
KamLAND detector The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
KamLAND Kamioka Liquied scintillator Anti-Neutrino Detector (since 2002) - 1,000 m depth (Kamioka mine) - 1,000 t liquid scintillator Dodecan (80%), Psedocumene (20%), PPO (1.36g/l) - 1,325 17inch + 554 20inch PMTs Φ 13m balloon (125 um thickness) Φ 18 stainless tank Outer detector (for muon veto) - 3.2kton water cherenkov detector - ~100 20inch PMTs
KamLAND Anti-neutrino detection: delayed coincidence measurement - time-spatial correlated events - Reduction of background events γ (511 keV) prompt e − e + ¯ p ν e γ (511 keV) n d n p γ (2.2 MeV) delayed
KamLAND The world cleanest detector Ions are billion time more solvable to water. Wash scintillator with pure water. 238 U 3.5x10 -18 g/g 232 Th 5.2x10 -17 g/g It is trillion times cleaner than ordinary material or 100 times cleaner than Super-Kamiokande.
Targets of KamLAND Largest anti-neutrino detector with ultimate low background. Different neutrino physics in a wide energy range
History of KamLAND
Latest results Reactor neutrino Geo-neutrino The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Anti-neutrino flux in Kamioka The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Expected spectrum Normal-reactor phase Low-reactor phase 4 6 8 0 0 4 6 8 2 2 Neutrino energy[Mev] “Reactor on-off” study for neutrino oscillation and geo-neutrino analysis
Observed spectrum The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
L/E plot The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Oscillation analysis The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Geo-neutrino
componential analysis of chondrite meteorite (Indirect measurement) Motivation of geo-neutrino Why ? Geo-neutrino can directly test radiogenic heat production and the BSE model(s).
Results of geo-neutrino The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Comparison with Models
Next challenges PreSN neutrino Proton decay Future projects The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
PreSN neutrino
ACTA PHYSICA POLONOCA B 40, 3063 (2009) PreSN neutrino Emitted neutrinos in Si burning phase before core-collapse supernova
ACTA PHYSICA POLONOCA B 40, 3063 (2009) PreSN neutrino Emitted neutrinos in Si burning phase before core-collapse supernova
3h 6h 12h 24h 48h Flux of PreSN neutrino Energy is low !! inverse-beta threshold (1.8MeV) Only high energy tail (>1.8MeV) is detectable Nearby events AIP Conference Proceedings 944, 109 (2007)
Candidates Nearby supergiants Red supergiants - Antares (170pc) - Betelgeuse (200pc) Wolf-Rayer star - Gamma Velorum (340pc)
No oscillation Normal Inverted Evis [MeV] Arbitary unit [/0.2MeV] Expected spectrum
48-24h 24-3h 3-0h Time 1.6 6.1 9.2 Normal 0.7 2.9 4.4 Inverted Expected values Model: Betelgeuse like star with d=200pc Number of events
3-0h 24-3h False rate/yr Inverted 93% 80% 19% Efficiency Normal 99.6% 98% 50% Efficiency 48-24h 48-24h 1.3 0.032 Inverted 4.4 2.9 0.7 Normal 9.2 6.1 1.6 Time 3-0h 24-3h 1.7 Expected values Model: Betelgeuse like star with d=200pc Number of events Detection efficiency (with present background level)
3-0h 24-3h False rate/yr Inverted 94% 62% 9.4% Efficiency Normal 99.9% 95% 31% Efficiency 48-24h 48-24h 1.6 0.38 Inverted 4.4 2.9 0.7 Normal 9.2 6.1 1.6 Time 3-0h 24-3h 2.4 Expected values Model: Betelgeuse like star with d=200pc Number of events Detection efficiency (reactor on)
Very early alarm KamLAND will detect PreSN neutrinos. Large uncertainty of detection efficiency: c - reactor status p 0 5 ± 0 0 2 : - neutrino mass hierarchy e s u e g l e t e B - uncertainty of distance - models of the stellar evolution Targets: Antares, Betelgeuse, and Gamma Velorum Very early alarm (before SN neutrino) Useful for astro committee and neutrino/GW detectors Not miss neutrino/GW from SN Excellent chance: - Measurement of optical shock wave - Study on the final stage of the stellar evolution We are developing the alarm system.
Proton decay
Proton decay KamLAND (and scintillator experiment): sensitive to K + SUSY SO(10): p → K + ¯ with τ ∼ 10 32 − 10 34 yr ν - Water Cherenkov detector : below the Cherenkov threshold (253MeV) K + Indirect measurement (efficiency ~5%): 5.9x10 33 yr - KamLAND is searching for with higher efficiency. p → K + ¯ ν decay channel K + K + → µ + ν µ (63.54%) K + → π 0 π + (20.68%)
Features of signal
Features of signal Prompt (double pulse) event Delayed event Asymmetry of 1st and 2nd peak
1 st pulse 1 st pulse + 2 nd pulse 2 nd pulse Simulation of double pulse fitting
MC simulation (efficiency) y y r e r a V n i m i l e r P
Life time ! ! n o o s g n i m o C
Future projects
Future projects CeLAND 4th neutrino search Ce source in KamLAND KamLAND-Pico Dark matter search NaI in KamLAND Check DAMA result 75kCi 144 Ce
Summary The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
KamLAND: the largest anti-neutrino detector Latest results Including reactor-off period - Improvements of oscillation parameter - Geo-neutrino measurement with low background Next challenges - PreSN monitor system - Proton decay (K + v) - CeLAND (4th neutrino) - KamLAND-Pico (dark matter) The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Geo-neutrino detection Beta-decay of radioactivities (U, Th, K) in the Earth
Energy spectrum reactor (α, n)
Results of geo-neutrino The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors
Rate + shape + time analysis
Expected events AIP Conference Proceedings, 944, 109 (2009)
Model Betelgeuse like star Stellar evolution - Mass: 20M - Distance: 200pc Oscillation F = pF ¯ ν e + (1 − p ) F ¯ ν x p : survival probability Astroparticle Physics Volume 21, Issue 3, June 2004, Pages 303–313
ACTA PHYSICA POLONIGA B, 41, 1611 (2010) Stellar evolution
48-24h 24-3h 3-0h Normal Inverted Statistics 200pc and low-reactor status (0.1 event/day)
0.4 0.68 Inverted >99% 81% 10% Efficiency Normal >99% >99% 42% Efficiency 3-0h 24-3h 48-24h 48-24h 0.032 0.6 Normal 24-3h 3-0h Efficiency 78%/55% >99% >99% Efficiency 1.3/0.034 41%/17% 96%/89% >99% Inverted False rate/yr 1.7/0.06 False rate/yr Detection efficiency 150pc and low-reactor status 150pc and normal status - Final stage is OK !! - Early alarm is possible (efficiency > 80%)
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