Sterile Neutrinos at the Crossroads, Blacksburg, VA Status of RENO Yeongduk Kim, Sejong University On behalf of RENO collaboration Sterile Neutrinos at the Crossroads, Blacksburg, VA 2011. 9. 25-28

Contents Q13 measurement with reactor neutrinos RENO overview Final Construction of RENO Calibration Data of RENO Summary

Reactor Neutrino Experiment at a Glance ν e + n Gd γ ~30μs Delayed signal E å ~ 8 MeV g prompt signal Inverse Beta Decay q13 Dominant sin2(213)=0.04 sin2(213)=0.1 sin2(213)=0.2 E (MeV) “near” “far” q12 Dominant

Reactor Sites Around the World Two Reactor Sites Multi-Reactor Sites Under Consideration Former Host Site Jonathan Link, Columbia U. Seminar 2003

RENO Sites Yonggwang Nuclear Power Plant near detector site 46.1 m 95 m reactor detector 1383.1 m 294.3 m ~256 m far detector site 168.1 m 272 m Yonggwang Nuclear Power Plant Six ~ 1 GWe class PWRs Total average thermal power of 16.4 GW (max 17.3 GW) Operational factor > 90%

RENO Detector 354 10” ID PMTs : 14% surface coverage 67 10” OD PMTs Both PMTs : HAMAMATSU, R7081 Mu-metal shielding for each PMT. (-5cm) No special reflector for ID Tyvek reflector at OD LAYER D (cm) H vessel Filled with Mass (tons) Target 280 320 Acrylic Gd(0.1%) +LS 16.5 Gamma catcher 400 440 LS 30.0 Buffer 540 580 SUS Mineral oil 64.4 Veto 840 880 Concrete water 352.6

Milestones in 2011 Detector closing (Jan.) Installation of electronics hut & control room (Feb.) DAQ electronics & HV supplying system, & cabling (Feb.) Installation of slow control & monitoring system (Jan. ~Jun.) Liquid scintillator production & filling (May ~ Jul.) Installation of 1D&3D calibration system (Jun..~ Aug.) Installation of water circulation system (Jul. ~ Aug.) Began regular data-taking & calibration (Aug. 1 ~)

Detector Construction & Closing (Jan. 2011) Near : Jan. 21, 2011 Far : Jan. 24, 2011

Completed RENO Detector (Feb. 2011) Liquid Scintillator Production System DAQ Electronics Calibration System Control Room

Dry Run Before filling liquids, we tested PMTs with a bottle of liquid scintillator & source at center. QBEE threshold is set to 1 mV for data taking. Charge(counts) discri. thr. -0.4mV -0.5mV -0.6mV -0.7mV -1.0mV 137Cs source Liquid Scintillator 1 Photoelectron peak

Gd-LS & LS Goal Gd-LS : 0.1% Gd , PPO 3g/L, bis-MSB 30mg/L  TARGET LS : PPO 3g/L, bis-MSB 30mg/L  GAMMACATCHER Concentrated Liquids Gd-LAB : 0.5% Gd ( X5 concentration) LS-Master : PPO 30 g/L, bis-MSB 300mg/L ( X10 concentration) LS batch (2000L) LAB (1800 L) + LS-Master (200L) Near/Far separate production & filling Gd-LS batch (2000L) LAB (1400 L) + LS-Master (200L) + Gd-LAB (400L) Produced in Far detector area and divided two

FAR NEAR LAB 10ton LAB 10ton GdLS LS (0.1 %) 2000L LS 2000L Water out LS master (x10) 200L Gd-LAB (0.5%) 400L Gd-sol TMHA LS LAB 10ton Water out Divide into two G.C. FAR LS master (x10) 200L LS 2000L LAB 10ton Water out G.C. NEAR

LS handling system Gd Loaded Liquid Scintillator

Liquids Production & Filling Gd-LS filling for Target Both near and far detectors are filled with Gd-LS, LS & mineral oil as of July 5, 2011. Gd-LS(18805L, <0.2% difference) Veto water filling is completed at the end of July, 2011. DAQ Electronics Gd Loaded Liquid Scintillator LS filling for Gamma Catcher Water filling for Veto

Water circulation system veto Circulation system Drain Local Water supply Ultra-pure water system is important for VETO efficiency. Solenoid valve : Auto on/off Feedback from the ultrasonic level sensor of Water level

Gain matching of PMTs 137Cs source in the center. PMT gains are set to 1.0x107 for all PMTs. gain variation between PMTs are within 3% for both detectors. Gain (107) # of PMTs

Electronics & Trigger Software trigger QBEE : each channel digitized if over threshold. All the hits are sorted in time and grouped into an event if number of hits exceeds preset trigger condition. (ID:90, OD:10) Pedestal hits are collected realtime Intrinsic charge Injector into each channel for electronics calibration. Types of Trigger : ID OD LASER PEDESTAL Charge Injector Data block(20ms) Software trigger 200ns “Software” event Merge the data From front-end PCs Number of hits exceeds the threshold, Send downstream

Laser calibration system Blue(420nm) Laser  Fiber optics (1 @ Top, 1 @Bottom, 3 @ Barrel) Optical Fiber+ Cosine Corrector Barrel Top Bottom Laser Q (degree)

1-D source driving systems Two identical source driving systems at the center of TARGET and one side of GAMMACATCHER.

Calibration w/ Gammas 68Ge 137Cs 60Co Preliminary Far Near 1.022 MeV 0.662 MeV Far Near 60Co 2.506 MeV Sources @ center. ~ 230 PE/MeV Near/Far show similar spectra.

252Cf - neutron Preliminary Far Near We are observing both Gd capture and hydrogen capture as expected by simulation. Capture time distribution and vertex reconstruction is in progress. Preliminary Gd(n,g) neutron capture signal p(n,g) neutron capture signal Far Near

Backgrounds – single rates. Trigger Conditions : BUFFER No VETO VETO NEAR ~280 70 ~533 FAR ~110 86 ~66 Background trigger rates over ~0.5MeV is comparable to the simulated rates over 1MeV.

Backgrounds – single rates Simulation(TDR) Background events with All triggers. Events/ (sec 65keV) NEAR FAR 3MeV

RENO Sensitivity on sin2(2q13) Statistical errors (3 years of data taking with 70% efficiency) Near : 9.83x105 ≈ 106 (0.1% error) Far : 8.74x104 ≈ 105 (0.3% error) T2K Systematic error : <0.5% * Sensitivity : sin2(2q13) > 0.02 at 90% C.L. 90% CL Limits

Summary Construction of both near and far detectors at RENO are completed in Feb. 2011. All the liquids are produced and filled by end of July 2011. Regular data-taking with NEAR & FAR detectors began from August 1, 2011. Data reduction, source calibration, and Monte-Carlo reconstruction efforts are on progress. RENO group hope to tell the value of sin2(2q13) at the anticipated time.

Backup Slides

Comparison of Reactor Neutrino Experiments Location Power (GW) Distances Near/Far(m) Depth Near/Far (mwe) Target Mass (tons) Double-CHOOZ France 8.7 400/1050 60/300 10/10 RENO Korea 17.3 290/1380 120/450 16/16 Daya Bay China 17.4 360(500)/1985(1613) 260/910 402/80 Detail numbers should refer to individual experiment.

Calibration Sources type source E(keV) Activity (m Ci) calibration gamma 137Cs 662 1 threshold e+ 68Ge 1022 0.014 Position, E threshold 60Co 2506(1173+1333) Multiple gamma neutron 252Cf Neutron+gammas ~8000 0.06 Neutron efficiency Gd concentration

Sterile neutrinos at RENO Both RENO detectors will see the deficit of neutrinos if sterile neutrinos exist. No L/E sensitivity except 0.1 eV2

Slow Monitoring System PMT HV Adjustment & Monitor (LABVIEW) A1932 primary current & individual HV return value. Detector Temperature (BUFFER, VETO) PT-100 thermocouple. Water Level Using ultrasonic sensor. Rn Monitoring Sun Nuclear 1027 model. Gas Concentration – CO2 & O2 KCD-HP500 : CO2 concentration measurement using IR absorption Honeywell XCD : O2 concentration Humidity & Temperature HTM420R IP Camera System

1D system configuration passive pulley active(motor) pulley glove box source case (acrylic) weight (teflon) Mechanical system wire pulley (circumference ~ 1 m) Control system