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Soo-Bong Kim Dept. of Physics & Astronomy Seoul National University April 15, 2009

A Korean Project of Neutrino Oscillations. Soo-Bong Kim Dept. of Physics & Astronomy Seoul National University April 15, 2009. 14 C b decay. Physics in trouble with b decay. Energy & momentum are not conserved. F. A. Scott, Phys. Rev. 48 , 391 (1935). Predicted discrete spectra.

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Soo-Bong Kim Dept. of Physics & Astronomy Seoul National University April 15, 2009

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  1. A Korean Project of Neutrino Oscillations Soo-Bong Kim Dept. of Physics & Astronomy Seoul National University April 15, 2009

  2. 14C bdecay Physics in trouble with bdecay Energy & momentum are not conserved F. A. Scott, Phys. Rev.48, 391 (1935) Predicted discrete spectra Observed continuous b spectra 14C  14N + e– spin 0 spin 1 spin 1/2 Birth of Neutrino Total spin is not conserved, either… Bohr: Energy and momentum may not be conserved inbdecay ?…

  3. Neutrino Wolfgang Pauli’s introduction of an imaginary particle(1931) Neutrino :Undetectable massless neutral fermion (Weakly interacting)

  4. Neutrino: Elementary Particles • Elementary particles with almost no interactions • Almost massless: impossible to measure its mass • Universe full of neutrinos

  5. SM GUT Tiny Neutrino Masses mass E=mc2 10-36kg 10-30kg 10-27kg

  6. Mixing Angles (12 , 23 , 13) Unmeasured yet Oscillating Neutrinos CKM Quark Mixing and CP Violation Discovery of Neutrino Oscillations (1998) • Three flavors of neutrinos repeat transformation among them as time goes by.

  7. Properties of Neutrinos • Almost no interaction with matter(via weak interaction only) • Mass is too small to measure • Universe full of neutrinos(330 per 1cm3) • Elementary particles with three flavors(ne, nm, nt) • Transformation among the three flavors

  8. Neutrino Oscillation andMass Window for New Physics ! Neutrinos are hot ! Why is the neutrino physics so improtant? Origin of Our Universe !!

  9. n2 nt nm q n1 n1 2-Neutrino Oscillation n2 nt nt nt Neutrino Oscillation • neutrino oscillations due to wave property of neutrino Flavor states Mass states n1 n2 m1 m2

  10. Neutrino trajectory Neutrino energy Oscillation Probability

  11. Solar Neutrino(e) Oscillations (12측정) Nuclear fusion : 4p → 4He + 2e+ + 2e + thermal energy • Deficit of solar neutrinos→Evidence for oscillations - Homestake (Cℓ,1968~1993): first measurement - Kamiokande (H2O, 1986~1993): energy/directionality - SAGE & GALLEX/GNO (Ga, 1990~2001) - Super-Kamiokande (H2O, 1996~): precision exp. • Discovery of Solar Neutrino Oscillations - SNO (D2O, 2002): detect  /(e →  & ) • Confirmation of Solar Neutrino Oscillations - KamLAND (2002): reactor neutrino oscillation

  12. Confirmation of atmospheric neutrino oscillations - K2K (2004) : accelerator beam(250km) - MINOSCNGS (2006) : ~700km Atmospheric Neutrino() Oscillations (23측정) Cosmic ray (p, He, …) + Atmosphere→ /K meson→  → e + • Discovery of atmospheric neutrino oscillations ( → ) - Super-Kamiokande (1998) - measurement of 23

  13. 23 13 12 • mass difference : Dm232 = 2.4(13% )10-3 eV2 ≈ Dm132 Dm122 = 7.9(5% )10-5 eV2 • mixing angles : sin212= 0.31(9%) sin213< 0.17 (90% C.L.) sin223= 0.44(+20–11% ) Summary of Neutrino Oscillation Parameters

  14. CP : CP phase Ue3 reactor and accelerator atmospheric SK, K2K SNO, solar SK, KamLAND 0 23 = ~ 45° 13 = ? 12 ~ 32° ? Large and maximal mixing! (Solar neutrinos & reactor neutrinos) (atmospheric neutrinos & neutrino beams) Precision Measurementof Neutrino Oscillation Parameters (New field of particle physics open!)

  15. mass hierarchy CP violation matter 13from Reactor and Accelerator Experiments * Reactor - Clean measurement of 13 - No matter effects * Accelerator - sin2213 is a missing key parameter for any measurement of CP

  16. 울진 영광 Reactor Neutrinos Reactor Neutrinos Nuclear Power Plants • 인체에 유해한 방사능(중성자, 알파선, 베타선, 감마선)은 원자로 내부에서 차폐됨 • 핵붕괴시 방출되는 중성미자는 물질과 거의 반응을 하지 않으므로 인체에 무해하며 원자로를 빠져 나와서 사방으로 끊임없이 퍼져 나감 (매초당 ~1017n/m2 방출) • 영광발전소는 열생산 최대용량이 17GW로서 세계 2위의 강력한 중성미자 방출원임

  17. Energy Spectra of Reactor Neutrinos

  18. Detection Method of Reactor Neutrinos(Reines & Cowan, 1957)

  19. n captureenergy e+ energy (1) 0.7<Eprompot <9MeV (2) 5<Edelayed <11MeV Detection of Reactor Neutrinos

  20. RENO (q13 ) Reactor Neutrino Experiments Chooz: q13<130 KamLAND (q12)

  21. Find disappearance of nefluxes due to neutrino oscillation as a function of energy using multiple, identical detectors New Reactor NeutrinoExperiment (q13) • Detectors should be at underground to reduce the cosmic-ray backgrounds • Need identical detectors to reduce the systematic errors in 1% level

  22. L~180km KamLAND: accurate Dm212 moderate q12 3s(RENO-q12) L~5km: Dm213 L~1.5km: pure sin22q13 L~50km: accurate sin22q12 Scope of RENO Project Oscillation Parameters from Reactor Neutrinos sin22q13=0.1, En=4MeV

  23. Disappearance Reactor neutrino disappearance Prob. due to 13 with the allowed 2 range in m232 Reduction of Reactor Neutrinos due to Oscillations • sin22q13 > 0.01 with 10 t• 14GW• 3yr ~ 400 t•GW•yr (400 t•GW•yr: a 10(40) ton far detector and a 14(3.5) GW reactor in 3 years)

  24. Double-CHOOZ (France) Double-Chooz Collaboration: France, US, Germany, Italy, Japan, England, Brasil, Spain & Russia * 2010년 근거리/원거리검출기 동시 가동 * Proposal (June 20, 2006) : hep-ex/0606025

  25. Daya Bay (China) Daya Bay Collaboration: China, US, Czech Republic, Hong Kong, Russia & Taiwan * Proposal to DOE (Jan. 15, 2007): hep-ex/0701029

  26. World Competition in the Reactor Neutrino Experiments

  27. RENO Collaboration • Chonnam National University • Dongshin University • Gyeongsang National University • Kyungpook National University • Pusan National University • Sejong University • Seoul National University • Sungkyunkwan University • Institute of Nuclear Research RAS (Russia) • Institute of Physical Chemistry and Electrochemistry RAS (Russia) +++ http://neutrino.snu.ac.kr/RENO

  28. RENO Experimental Setup

  29. Google Satellite View of YongGwang Site

  30. 200m high Near Detector Reactors 70m high 100m 300m 290m 1,380m Far Detector Schematic View of Underground Facility

  31. Activities 2009 2006 2007 2008 12 12 12 12 3 3 3 3 6 6 6 6 9 9 9 9 Detector Design & Specification Geological Survey & Tunnel Design Detector Construction Tunnel excavation Detector construction Detector Commissioning Schedule for RENO Construction

  32. Rock sampling (DaeWoo Engineering Co.) Rock samples from boring

  33. Far detector site: • tunnel length : 272m • overburden • height : 168.1m Rock quality map • Near detector site: • tunnel length : 110m • overburden • height : 46.1m

  34. Stress analysis for tunnel design

  35. Mixing & Supplying Liquid Scintillators • Data Acquisition System

  36. Mockup Detector Event Display Real time display: Online monitoring tool Basic information on histograms PMT hit display

  37. RENO Detector • RENO Detector Design and Specification

  38. Structure design completed (’08. 12)

  39. PMT test completed & under purchase

  40. DAQ Electronics completed (’08. 11) • Use SK new electronics • 광센서의 신호를 초고속 처리하는 ASIC을 사용한 데이터 수집 장비

  41. R&D of Gd Loaded Liquid Scintillator • Mixing for Liquid Scintillator : • LAB(Linear Alkyl Benzene) Properties: Light yield measurement CnH2n+1-C6H5 (n=10~14) PC100% LAB100% PC40% PC20% LAB100% PC20% N2 LAB60% LAB80% MO80% • 0.1% Gd compounds with CBX (Carboxylic acids; R-COOH) 합성 연구 : - CBX : TMHA (trimethylhexanoic acid), MVA (2-methylvaleric acid)

  42. precipitation Synthesis of Gd-carboxylate Rinse with 18MΩ water Dryer

  43. R&D with LAB CnH2n+1-C6H5 (n=10~14) PC와 Mineral oil/Dodecane 대용으로 사용할 수 있는 LAB(Linear Alkylbenzene)의 분자 구조식 Light yield measurement • High Light Yield : not likely Mineral oil(MO) • replace MO and even Pseudocume(PC) probably • Good transparency (better than PC) • High Flash point : 147oC (PC : 48oC) • Environmentally friendly (PC : toxic) • Components well known (MO : not well known) • Domestically available:Isu Chemical Ltd. (이수화학) PC100% LAB100% PC40% PC20% LAB100% PC20% N2 LAB60% LAB80% MO80%

  44. LAB : (C6H5)CNH2N+1 C16H26 C17H28 C18H30 C19H32 7.17% 27.63% 34.97% 30.23% # of H [m-3] = 0.631 x 1029 H/C = 1.66 Measurement of LAB Components with GC-MS

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