Current Status of RENO Jaison Lee (Seoul National Univ.) for RENO Collaboration 2009/12/17, KISTI

New Reactor Neutrino  13 Experiment  Lower background - Improved detector design - Increased overburden  CHOOZ : R osc = 1.01 ± 2.8% (stat) ± 2.7% (syst)  Larger statistics - More powerful reactors (multi-core) - Larger detection volume - Longer exposure  Smaller experimental errors - Identical multi detectors → Obtain ~1% precision !!! arXiv: v2, Fogli et. al. Hint of  13 >0 from different data sets and combinations : 1  range

Detection of Reactor Neutrinos data from CHOOZ hep-ex/ v1 (3) 1μs<ΔT <200μs (1) 0.7<E prompot <9MeV e + energy (2) 5<E delayed <11MeV n capture energy

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

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) +++

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

Google Satellite View of YongGwang Site

Schematic Setup of RENO at YongGwang

RENO Detector Inner Diameter (cm) Inner Height (cm) Filled with Mass (tons) Target Vessel Gd(0.1%)+LS16.1 Gamma catcher LS28.5 Buffer tank Mineral oil64.4 Veto tank840880water352.6 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. Steel/acrylic containers and mechanical structures are under installation and will be completed until Nov , 2008 : SK new electronics were adopted and ready. PMT installation is expected to start from Dec Both near and far detectors are expected to be ready for data-taking in mid , 2008 : A mockup detector (~1/10 in volume) was built and is tested out.

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~ )

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

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

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 : MVA (2-methylvaleric acid), 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 )

Optical Properties of Liquid Scintillator LS Attenuation Length ~ nm LS Emission Spectrum

Refractive Index of Detector Materials

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

J μ [cm -2 s -1 ] [GeV] Far 250 m2.9× m8.5× Near70 m5.5× Muon intensity at the sea level using modified Gaisser parametrization + MUSIC or Geant4 (the code for propagating muon through rock) Calculation of Muon Rate at the RENO Underground

Con(K)Con(Th)Con(U)SER(K)SER(Th)SER(U)Total Rock 4.33(ppm)7.58(ppm)2.32(ppm) Target< 0.32 (a) < < 5.6 TargetV ( c) G.C.< 0.32 (a) < < 8.4 G.C.V (c) Buffer BufferV (d) PMT (b) Total< 34.6 (Concentration : ppt) (a)AAS (Atomic Absorption Spectroscopy) : resolution : ±5% (b)Low radioimpurity glass (c)Suspicious (8.2(K), <50(Th), 8(U) : Kamland Acrylic) (d)Quoted from Kamland Calculation of Background Rates due to Radioactivity

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) Double Chooz Near : 500/day Far : 70/day

RENO Expected Sensitivity 90% CL Limits Discovery Potential” (3  )

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

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 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.