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KamLAND Future Prospects

Atsuto Suzuki. KamLAND Future Prospects. Tohoku University. KamLAND Collaboration. III Int. Workshop on Neutrino Oscillations in Venice Feb. 7-10, 2006. Outline. KamLAND-II Prospects of Solar Neutrino Detection 3. Toward Precise Measurement of

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KamLAND Future Prospects

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  1. Atsuto Suzuki KamLAND Future Prospects Tohoku University KamLANDCollaboration III Int. Workshop on Neutrino Oscillations in Venice Feb. 7-10, 2006

  2. Outline • KamLAND-II • Prospects of Solar Neutrino Detection • 3. Toward Precise Measurement of • Reactor Neutrinos • 4. More and more Geoneutrinos • Conclusions

  3. 180 km 1. KamLAND-II (summer in 2006) ※7Be solar neutrino detection: JSPS 5-year project from 2004 ※Precise measurements of reactor-, geo- and solar neutrinos: MEXT 5-year project from 2005 300 KamLAND-II

  4. single events in KamLAND 10-5 ~ 10-6 2. Prospects of Solar Neutrino Detection

  5. distillation test bench 212Pb 222Rn R~10-2 222Rn : 4x10-3 >R > 5x10-4 85Kr : 4x10-5 >R > 5x10-6 Test Bench Studies N2 purge test bench

  6. impurities present goal reduction distillation purge 238U 232Th 40K 85Kr 210Pb (3.5 ± 0.5) x 10-18 g/g (5.2 ± 0.8) x 10-17 g/g < 2.7 x 10-16 g/g ~ 1 Bq/m3 ~ 10-20 g/g 10-16 g/g 10-16 g/g 10-18 g/g ~1 mBq/m3 ~10-25 g/g OK OK 10-2 10-6 10-5 < 10-2 < 10-5 < 10-4 < 10-5 purification system installation : until this July space for new purification system (May 2005) Background Reduction Status

  7. Expected Energy Spectrum in KamLAND-II 100 days data 210Po 85Kr events (0.3 <E< 0.8 MeV) / day / fid. (R< 4m) 7Be (80) , CNO (16), pep (4) , 85Kr (8), 210Bi (<2), 210Po (<1), 40K (3)

  8. Seasonal Flux Variation of Solar Neutrinos 3 years data in KamLAND-II events (0.3 <E< 0.8 MeV)/ day / fid. (R < 4m) 7Be (80) , CNO (16), pep (4) , 85Kr (8), 210Bi (<2), 210Po (<1), 40K (3)

  9. Possibility to Detect CNO and pep Neutrinos CNO+pep

  10. Present KamLAND Data DL < 50 cm along m : # of neutrons > 0 11C with DR < 150 cm (DR : distance from the nearest n) Dt 100 200 (min.) energy 1.2 1.4 1.6 1.8 (MeV) DR 200 400 600 800 (cm) 11C Identification

  11. New Electronics for Identifying Successive Multiple Events new (dead-time free)

  12. Expected Energy Spectrum in CNO+pep Region 90% rejection of 11C 3 years data 7Be 11C CNO pep

  13. 7Be CNO pep background subtracted neutron tagging efficiency ~ 100% 3 years data

  14. shape-analysis ( ne nx : 2-flavor case ) Nobs – NBG Nexpected LMA II: disfavored at 98.0% CL LAM I =0.686 ± 0.044 (stat) ± 0.045 (syst) LAM 0: disfavored at 97.5% CL disappearance: 99.995 % CL 3. Toward Precise Measurement of Reactor Neutrinos

  15. Off-Axis Calibration System g n 12N, 12B,… m Improvement of Detector Systematic Error energy scale, timing, g detection, n capture time, n detection, trigger efficiency, light transport,…. radioactive sources, laser system, LEDs, cosmic-ray m, m –induced spallation products 68Ge : 1.012 MeV (g + g) 65Zn : 1.116 MeV (g) 60Co : 2.506 MeV (g+g) AmBe : 2.20 , 4.40, 7.6 MeV (g) 6.5 %  4 % total uncertainty

  16. Setting Off-Axis System

  17. statistics x 10 limit due to 4% systematic error Updated Oscillation Parameters statistics x 5 systematic error : 4% statistics x 10 systematic error : 4% statistics x 5

  18. ne ne ne ne ne G. Gamow: 1953 4. More and More Geoneutrinos

  19. Background # of events 2.38 ±0.01 Accidental Coincidence Events/0.17 MeV 42 ±11 13C (a,n) 16O Reactor ne short lived long lived best fit 80.4 ±7.2 1.9 ±0.2 Antineutrino Energy (MeV) Total 127 ±13 Geoneutrino Result in KamLAND KamLAND Th U signal 152

  20. 2 years data in KamLAND-II CL 68.3% CL 95.4% CL 99.7% Th/U~3.9 NU + NTh best fit (NU – NTh)/(NU + NTh) Constraints on FU +FTh&FU /FTh in KamLAND-II BSE model best fit

  21. Th/U~3.9 2 years data in KamLAND-II

  22. Conclusions KamLAND-II provides • high rate detection of 7Be solar neutrinos, • chance to detect CNO + pep solar neutrinos, • stringent constraint on Dm2 for reactor neutrinos, • more constraint on U+Th (geoneutrinos), • and • interesting test of U/Th (geoneutrinos)

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