Soo-Bong Kim Seoul National Univ.

1. RENO for Neutrino Mixing Angle q13 (“Neutrinos in Cosmology, in Astro-, Particle- and Nuclear Physics” Sep. 16-24, 2009, Erice/Sicily, Italy) Soo-Bong Kim Seoul National Univ.

2. Hint of q13 >0 from different data sets and combinations : 1s range arXiv:0905.3549v2, Fogli et. al. New Reactor Neutrino q13Experiment • CHOOZ : Rosc = 1.01 ± 2.8% (stat) ± 2.7% (syst) → Obtain ~1% precision !!! • Larger statistics - More powerful reactors (multi-core) - Larger detection volume - Longer exposure • Smaller experimental errors - Identical multi detectors • Lower background - Improved detector design - Increased overburden

3. (3) 1μs<ΔT <200μs n captureenergy e+ energy (1) 0.7<Eprompot <9MeV (2) 5<Edelayed <11MeV data from CHOOZ hep-ex/0301017v1 Detection of Reactor Neutrinos

4. RENO Collaboration (11 institutions and 40 physicists) • Chonnam National University • Dongshin University • Gyeongsang National University • Kyungpook National University • Pusan National University • Sejong University • Seoul National University • Sungkyunkwan University • Seokyeong University • Institute of Nuclear Research RAS (Russia) • Institute of Physical Chemistry and Electrochemistry RAS (Russia) +++ http://neutrino.snu.ac.kr/RENO

5. Comparison of Reactor Neutrino Experiments

6. Schematic Setup of RENO at YongGwang

7. Google Satellite View of YongGwang Site

8. 200m high Near Detector Reactors 70m high 100m 300m 290m 1,380m Far Detector Schematic View of Underground Facility

9. RENO Detector 421(354+61) 10” PMTs total ~460 tons

10. Schedule

11. Summary of Construction Status • 03~10, 2007 : Geological survey and tunnel design are completed. • 07~11, 2008 : Construction of both near and far tunnels are completed. • 12, 2008 ~ 03, 2009 : Veto tanks and peripheral facilities (electricity, air circulation, drainage, network, etc.) are completed. • 10, 2008 : A mockup detector (~1/10 in volume) was built and is tested out. • 11, 2008 : SK new electronics wereadopted and ready. • Steel/acrylic containers and mechanical structures are under installation and will be completed until Nov. 2009. • PMT installation is expected to start from Dec. 2009. • Both near and far detectors are expected to be ready for data-taking in mid 2010.

12. Far detector site: • tunnel length : 272m • overburden • height : 168.1m Rock quality map (2007.3~2007.8) • Near detector site: • tunnel length : 110m • overburden • height : 46.1m

13. Design of Tunnels (2007.9~2007.11) Wing tunnel(L) Access tunnel Experimental hall Wing tunnel(C) Detector Experimental hall Access tunnel Wing tunnel(C) Detectorvertical hall

14. Near & far tunnels are completed (2008.6~2009.3) by Daewoo Eng. Co. Korea

15. Detector vertical halls are ready (2008.12~2009.2)

16. Buffer steel tanks are installed (2009.6~2009.9) by NIVAK Co. Korea

17. Acrylic vessels will be ready in Nov. 2009 (2009.7~2009.11) by KOATECH Co. Korea Gamma catcher Target Bending acrylic plates A half of target

18. Mockup Detector Target + Gamma Catcher Acrylic Containers (PMMA: Polymethyl Methacrylate or Plexiglass) Buffer Stainless Steel Tank ~1/10 of RENO in volume

19. Mockup Detector Assembly

20. Energy Calibration of Mockup Detector 252Cf 60Co 137Cs 60Co 137Cs

21. Electronics • Use SK new electronics (all hardwares are ready) Conceptual design of the system

22. 0.1% Gd compounds with CBX (Carboxylic acids; R-COOH) - CBX : MVA (2-methylvaleric acid), TMHA (trimethylhexanoic acid) Gd Loaded Liquid Scintillator CnH2n+1-C6H5 (n=10~14) • Recipe of Liquid Scintillator • High Light Yield : not likely Mineral oil(MO) • replace MO and even Pseudocume(PC) • 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)

23. RACFrameWork Raw/MC Data Production Modules Reconstruction Modules User Analysis Modules User ntuples RENOAnalysisControl • default modules data input and output, database access for run configuration and calibration • Has talk-to functionfor changing input parameters without recompiling • Addition of modules by user • Modules can be set as filter modulefor selecting events • Easy to use and build in RENO software environment

24. 4 MeV(KE) e+ y sy (mm) |y| Evis (MeV) 1 MeV (KE) e+ PMT coverage, resolution ~210 photoelectrons per MeV visible energy Reconstruction : vertex & energy • Reconstructed vertex:~8cm at the center of the detector • Energy response and resolution:

25. time pulse height OD PMTs A ~140cm Veto (OD) B ~40cm Buffer (ID) target ID PMTs g-catcher buffer C ~120cm D Reconstruction of Cosmic Muons

26. RENO Event Display

27. Calculation of Background Rates due to Radioactivity

28. Systematic Uncertainty Goals

29. 3 years of data taking with 70% efficiency Near : 9.83x105 ≈ 106 (0.1% error) Far : 8.74x104 ≈ 105 (0.3% error) Expected Number of Neutrino Events at RENO • 2.73 GW per reactor ⅹ 6 reactors • 1.21x1030 free protons per targets (16 tons) • Near : 1,280/day, 468,000/year • Far : 114/day, 41,600/year

30. RENO Expected Sensitivity 90% CL Limits Discovery Potential” (3s)

31. New!! (full analysis) RENO Expected Sensitivity 10x better sensitivity than current limit

32. SK Dm2 GLoBES group workshop@Heidelberg – Mention’s talk

33. Status Report of RENO • RENO is suitable for measuring q13 (sin2(2q13) > 0.02) • Geological survey and design of access tunnels & detector cavities are completed → Civil constructionwas finished in February, 2009. • Buffer steel containers are installed. • RENO is under installation phase. • Data –taking is expected to start in mid 2010. • International collaborators are being invited.