Soo-Bong Kim Seoul National Univ. RENO for Neutrino Mixing Angle  13 5 th International Workshop on Low Energy Neutrino Physcis (Neutrino Champagne LowNu 2009) Oct , 2009, Reims, France)

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) +++

Comparison of Reactor Neutrino Experiments ExperimentsLocation Thermal Power (GW) Distances Near/Far (m) Depth Near/Far (mwe) Target Mass (tons) Cost (US $) Double-CHOOZFrance8.7410/ /30010/10~35M RENOKorea / /45016/16~10M Daya BayChina (500)/1985(1613)260/  2/80 ~60M

Schematic Setup of RENO at YongGwang

Schematic View of Underground Facility 100m300m 70m high 200m high 1,380m290m Far Detector Near Detector Reactors

Google Satellite View of YongGwang Site

RENO Detector Inner Diameter (cm) Inner Height (cm) Filled withMass (tons) Target Vessel Gd(0.1%) + LS 16.1 Gamma catcher LS28.5 Buffer tank Mineral oil64.4 Veto tank water352.6 total ~460 tons 421(354+61) 10” PMTs

Schedule

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 were adopted and ready. Steel/acrylic containers and mechanical structures are under installation and will be completed until Nov PMT installation is expected to start from Dec Both near and far detectors are expected to be ready for data-taking in mid 2010.

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

Design of Tunnels Experimental hall Wing tunnel(L) Wing tunnel(R) Detector Wing tunnel(R) Access tunnel Detector vertical hall (2007.9~ )

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

Detector vertical halls are ready ( ~2009.2)

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

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

Mockup Detector Target + Gamma Catcher Acrylic Containers (PMMA: Polymethyl Methacrylate or Plexiglass) TargetDiameter61 cm Height60 cm Gamma Catcher Diameter120 cm Height120 cm BufferDiameter220 cm Height220 cm Buffer Stainless Steel Tank ~1/10 of RENO in volume

Mockup Detector Assembly

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

Electronics  Use SK new electronics (The system is assembled into DAQ) Conceptual design of the system

Gd Loaded Liquid Scintillator  Recipe of Liquid Scintillator Aromatic Solvent & Flour WLSGd-compound LABPPO + Bis-MSB 0.1% Gd+TMHA (trimethylhexanoic acid)  0.1% Gd compounds with CBX (Carboxylic acids; R-COOH) - CBX : TMHA (trimethylhexanoic acid) C n H 2n+1 -C 6 H 5 (n=10~14) High Light Yield : not likely Mineral oil(MO) replace MO and even Pseudocume(PC) Good transparency (better than PC) High Flash point : 147 o C (PC : 48 o C) Environmentally friendly (PC : toxic) Components well known (MO : not well known) Domestically available: Isu Chemical Ltd. ( 이수화학 )

Raw/MCDataProductionModulesReconstructionModulesUserAnalysisModulesUserntuples RACFrameWork default modules data input and output, database access for run configuration and calibration Has talk-to function for changing input parameters without recompiling Addition of modules by user Modules can be set as filter module for selecting events Easy to use and build in RENO software environment R Analysis Control RENO Analysis Control

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

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

RENO Event Display

Calculation of Background Rates due to Radioactivity Concentration 40 K (ppb) Concentration 232 Th (ppb) Concentration 238 U (ppb) 40 K [Hz] 232 Th [Hz] 238 U [Hz] Total [Hz] Rock4.33(ppm)7.58(ppm)2.32(ppm) LS in Target Target Contatiner LS in Gamma Catcher Gamma Catcher Container LS in Buffer Buffer Tank PMT Total~38.4

Systematic Uncertainty Goals Systematic SourceCHOOZ (%)RENO (%) Reactor related absolute normalization Reactor antineutrino flux and cross section 1.9< 0.1 Reactor power Energy released per fission0.6< 0.1 Number of protons in target H/C ratio Target mass0.3< 0.1 Detector Efficiency Positron energy Positron geode distance Neutron capture (H/Gd ratio)1.0< 0.1 Capture energy containment Neutron geode distance Neutron delay Positron-neutron distance Neutron multiplicity combined2.7< 0.5

Expected Number of Neutrino Events at RENO 2.73 GW per reactor ⅹ 6 reactors 1.21x10 30 free protons per targets (16 tons) Near : 1,280/day, 468,000/year Far : 114/day, 41,600/year 3 years of data taking with 70% efficiency Near : 9.83x10 5 ≈ 10 6 (0.1% error) Far : 8.74x10 4 ≈ 10 5 (0.3% error)

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

90% CL Limits Discovery Potential” (3  )

GLoBES group – Mention’s talk SK  m 2

Status Report of RENO  RENO is suitable for measuring  13 (sin 2 (2  13 ) > 0.02)  RENO is under final installation phase.  Geological survey and design of access tunnels & detector cavities are completed → Civil construction was finished in February,  International collaborators are being invited.  Data –taking is expected to start in mid  Buffer steel containers are installed.