Reactor Neutrino ExperimentsReactor Neutrino Experiments

Jun Cao

caoj@ihep.ac.cn

Institute of High Energy Physics

Lepton-Photon 2007, Daegu, Aug. 13-18, 2007

2 OutlineOutline

Past Reactor Neutrino Experiments Palo Verde Chooz KamLAND

Theta13 experiments Angra Daya Bay Double Chooz RENO

Search for neutrino magnetic moment TEXONO

Summary

3 Past Reactor Neutrino ExperimentsPast Reactor Neutrino Experiments

Reactor anti-neutrino experiments have played a critical role in the 50-year-long history of neutrinos.

The first neutrino observation in 1956 by Reines and Cowan.

Determination of the upper limit of mixing angle theta13 to sin2213<0.17 (Chooz, Palo Verde)

The first observation of reactor anti-neutrino disappearance at KamLAND in 2003.

Now reactor neutrino experiments become prominent again for measuring mixing angle 13 precisely.

4 Savannah River ExperimentSavannah River Experiment

The first neutrino observation in 1956 by Reines and Cowan. Inverse beta decay in CdCl3 water solution coincidence of prompt and

delayed signal Liquid scintillator + PMTs Underground

A modern experiment is still quite similar, except Larger, better detector Deeper underground, better passive and active shielding Now we know how to load Gd into liquid scintillator

e nep 2e e

Capture on H, or Gd, Cd, etc.Delayed signal

Prompt signal

5 Reactor Neutrino SpectraReactor Neutrino Spectra

235U, 239Pu, 241Pu beta spectra were measured at ILL. 238U spectrum is calculated theoretically.

Counting rate and spectra were verified by Bugey and Bugey-3 Power fluctuation <1%, counting rate precision ~2% with burn-up evolution. Spectra precision ~2% Rate and spectra precision are less important for next theta13 experiments.

Peak at 4 MeV

6 CHOOZCHOOZ

Baseline 1.05 km 1997-1998, France

8.5 GWth

300 mwe

5 ton 0.1% Gd-LS

Bad Gd-LS

Parameter Relative error

Reaction cross section 1.9 %

Number of protons 0.8 %

Detection efficiency 1.5 %

Reactor power 0.7 %

Energy released per fission 0.6 %

Combined 2.7 %

R=1.012.8%(stat) 2.7%(syst), sin2213<0.17

Eur. Phys. J. C27, 331 (2003)

7 Palo VerdePalo Verde

1998-1999, US

11.6 GWth

Segmented detector

12 ton 0.1% Gd-LS

Shallow overburden

32 mweBaseline 890m & 750m

R=1.012.4%(stat) 5.3%(syst)

Palo Verde Gd-LSChooz Gd-LS

1st year 12%, 2nd year 3%

60%/year

Phys.Rev.D64, 112001(2001)

8 KamLANDKamLAND

2002-now, Japan

53 reactors, 80 GWth

1000 ton normal LS

2700 mwe

Radioactivity fiducial cut, Energy threshold

Baseline 180 km

9 KamLANDKamLAND

The first observation of reactor anti-neutrino disThe first observation of reactor anti-neutrino disappearanceappearance

Confirmed antineutrino disappearance at 99.998Confirmed antineutrino disappearance at 99.998% CL% CL

Excluded neutrino decay at 99.7% CLExcluded neutrino decay at 99.7% CL

Excluded decoherence at 94% CLExcluded decoherence at 94% CL

R=0.6580.044(stat) 0.047(syst) Phys.Rev.Lett. 94, 081801 (2005)

2 0.6 5 212 0.5

2 0.1012 0.07

7.9 10

tan 0.40

m eV

10 Neutrino OscillationNeutrino Oscillation

Neutrino Mixing: PMNS Matrix

13 113

13 13

2 12

12 123 2 23

23 23

cos 0 si1 0 0

0 cos s

n

0 1 0

cos sin 0

sin cos 0

sin

in

0 0sin cos 00 cos 1

i

i

e

e

Atmospheric, K2K, MINOS, T2K, etc.

23 ~ 45º

SolarKamLAND12 ~ 30º

ReactorAccelerator13 < 12º

Known: |m232|, sin2223, m2

21, sin2212

Unkown: sin2213, CP, Sign of m232

“We recommend, as a high priority, …, An expeditiously deployed multi-detector reactor experiment with sensitivity to e disappearance down to sin2213=0.01” ---- APS Neutrino Study, 2004

11 Precisely Measuring theta13Precisely Measuring theta13

Parameter Relative error By Near/far configuration

Reaction cross section 1.9 % Cancel out

Number of protons 0.8 % Reduced to ~0.3%

Detection efficiency 1.5 % Reduced to 0.2~0.6%

Reactor power 0.7 % Cancel out or reduced to ~0.1%

Energy released per fission 0.6 % Cancel out

Chooz Combined 2.7 %

Major sources of uncertainties: Reactor related ~2% Detector related ~2% Background subtraction

Lessons from past experience: Need near and far detectors Chooz: Good Gd-LS Palo Verde: Go deeper KamLAND: No fiducial cut, lower threshold

4 MeV

12 Proposals for measuring Proposals for measuring 1313

Angra, Brazil

Diablo Canyon, USA

Braidwood, USA

Double Chooz, France

Krasnoyarsk, Russia

KASKA, Japan

Daya Bay, China

RENO, Korea

8 proposals

4 cancelled

4 in progress

13 AngraAngra

Goal: sin2213 ~ 0.006 @ 90% CL. Site: Rio de Janeiro, Brazil

30 researchers from 11 institutions. Budget for Very Near (prototype) detector for Safeguards study approved by

FINEP in March 2007 (~$0.5M) High precision theta13 experiment in Angra around 2013? Participation of the Brazilian group in Double Chooz experiment

4GW+1.8GW

14 Daya BayDaya Bay

Goal:

LA: 40 tonBaseline: 500mOverburden: 112mMuon rate: 0.73Hz/m2

Far: 80 ton1600m to LA, 1900m to DYBOverburden: 350mMuon rate: 0.04Hz/m2

DYB: 40 tonBaseline: 360mOverburden: 98mMuon rate: 1.2Hz/m2

Access portal

8% slope

0% slope

0% slope

0% slope

Goal: sin2213 < 0.01 @ 90% CL in 3 years. Site: Shen Zhen, China

Power Plant4 cores 11.6 GW6 cores 17.4 GW from 2011

Three experimental hallsMultiple detectors at each siteSide-by-side calibration

Horizontal TunnelTotal length 3200 m

Movable DetectorAll detectors filled at the filling hall, w/ the same batch of Gd-LS, w/ a reference tank

Event Rate:~1200/day Near~350/day Far

BackgroundsB/S ~0.4% NearB/S ~0.2% Far

15 Daya Bay DetectorDaya Bay Detector

RPC

Water Cherenkov

Antineutrino detector

Eight 3-layer cylindrical anti-neutrino detectors, 5mx5m Target mass 20 ton. Stable 0.1% Gd-LS by IHEP&BNL: [Gd+carboxylic]+LAB+fluor Gamma catcher ~ 42cm, LAB+fluor Oil Buffer ~ 50 cm, 192 8-in PMTs + reflective panels. Energy resolution ~12%/sqrt(E) Water shield (2 layer water cherenkov) ~ 250 cm, ~2000 ton. 4 layer RPC at top.

20 t Gd-LS

Gamma CatcherOil Buffer

Reflective panel

16 Civil ConstructionCivil Construction

Underground Filling in hall 5 Significantly reduce detector systematic uncertainties. Same batch of Gd-LS and LS

H/Gd ratio, H/C ratio, light properties

A reference tank with load cell to fill all detectors Target mass 0.1-0.2%

Site Survey, bore hole 2005.5-2006.6

Conceptual Design 2006.6-2006.8

Preliminary Design 2007.1-2007.3

Engineering Design 2007.3-2007.7

Civil Bidding 2007.8-2007.9

Start civil construction 2007.9

Complete civil construction 2009.6

Hall 5: LS mixing and filling

200t Gd-LS

200t LS 200t Oil

17 Daya Bay StatusDaya Bay Status

~180 collaborators, 34 institutes from China (Taiwan, Hong Kong), Czech, Russia, and United States.

All funding from China (all civil and ~50% detector) is secured. Passed US DOE physics review (2006.10) and CD1 review (2007.4).

R&D funding approved. CD2/3a review scheduled in 2007.11. Detector construction funding (~50% detector) expected shortly after CD2/3a .

Funding from Taiwan, Czech, Russia is secured.

ScheduleStart Tunnel Construction ……………… 2007. 09Surface Assembly Building ready ……… 2008. 06DB Near Hall civil complete …………… 2008. 07DB Near Site ready to take data ………. 2009. 06LA Near Site ready to take data ……… 2010. 05All Sites Ready to take Data…………… 2010. 10

90% C.L.

18 Daya Bay R&DDaya Bay R&D

A 2-layer prototype running at IHEP for 1.5 years. Outer detector: 2mx2m, Inner acrylic vessel: 1mx1m. Phase-I with 800 liters normal LS for 1 year. Phase-II with 800 liters 0.1% Gd-LS has been running for 7 months.

A 2-layer prototypes is under construction in Hong Kong. (underground) 3-m and 4-m Acrylic Vessel prototype will be completed before 2007.11 All critical detector components are being prototyped, e.g. water system, r

eflectors, RPC chamber, electronics, PMT base and seal, etc.

Prototype with 45 8” PMTsStability monitoring of 800-L 0.1% Gd-LS in IHEP prototype. No visible attenuation length degradation.

19 Double ChoozDouble Chooz

Goal: sin2213 < 0.03 @ 90% CL in 3 years

Ardennes, France

Far detector (1050 m)300 m.w.e.

Near detector (~280 m)~80 m.w.e.

ν νν

νννν

2 reactors - 8.5 GWth 2 identical detectors:

►Target: 2 x 8.3 t Comparison of neutrino rate & energy spectrum Civil work:

► 1 near lab is foreseen► 1 far lab is available

Far site already exists

20 Double Chooz DetectorDouble Chooz Detector

3-layer cylindrical detector Target mass 8.3 ton. Stable Gd-LS by Heidelberg: [Gd+Beta-Dikotonates]+[20% P

XE+80% dodecane]+fluor Gamma catcher ~ 54cm, normal LS Oil Buffer ~ 100 cm, 390 10-in PMTs Veto ~ 50 cm, shielding 15cm

21 Double Chooz StatusDouble Chooz Status

Proposal of the experiment (hep-ex/0606025) Technical Design Report almost finished Funding has been established in Europe

NSF groups in US funded Japan and US DOE groups pending

The experiment is moving forward Schedule:

2007-2008: Detector construction and integration 2008: Far detector data taking starts, sin2213 < 0.06 (90% CL)

2010: Near detector starts

~100 scientists, 32 institutions from Brazil, France, Germany, Japan, Russia, Spain, UK, and US.The experiment has been approved by most of the respective Scientific Councils

90% C.L. m2atm = 2.8 10-3 eV2

22 RENORENO

YongGwang NPP, Korea

6 cores, 16.4 GWGoal: sin2213 ~ 0.02 @ 90% CL in 3 years

23 RENO DetectorRENO Detector

Target 15-t 0.1% Gd-LS, [Gd+CBX or BDK] + [20%PC+80% dodecane] + fluor, R&D by INR/IPCE group

Gamma Catcher ~60 cm Oil Buffer ~70 cm, 537 8-in PMTs,

7.7%/sqrt(E) Water veto ~1 m, PMT number un

determined.

24 RENO StatusRENO Status

Experiment site usage has been approved.

Geological survey completed in 2007.05 Issue tunnel construction contract in

2007.10 Detector Construction begin in 2007.10 Data taking expected to start in early

2010.

43 collaborators, 13 institutes from Korea, Russia

Project was approved for funding in 2005 with 10M USD.

25 RENO R&DRENO R&D

Small prototype running Working on “mock-up” detector Gd-LS R&D

4-L Gd-LS

140-L gamma catcher

26

TEXONO Collaboration – Academia Sinica-based and run, with groups from China, Turkey & India, close partnership with KIMS group in Korea.

Facilities – Kuo-Sheng Reactor Neutrino Laboratory in Taiwan; YangYang Underground Laboratory in South Korea.

Program – Low Energy Neutrino and Astroparticle (Dark Matter) Physics. Neutrino Magnetic Moments, Neutrino Radiative Decays, Axions

Y2L

TEXONO TEXONO

27 Reactor Neutrino Interaction Cross-SectionsReactor Neutrino Interaction Cross-Sections

R&D (ULEGe) : Coh. (N)

T < 1 keV

Results (HPGe):

(e)

T ~ 1-100 keV

On-Going Data Taking & Analysis [CsI(Tl)] : SM (e)

T > 2 MeV

massquality Detector requirements

Bkg level at O(10 keV)~ 1 counts / kg-keV-day

28 TEXONO 2007 HighlightsTEXONO 2007 Highlights

Improved Limits in Neutrino Magnetic Moments (PRL-03, PRD-07)

e < 7.4 X 10-11 B @ 90% CL

Bounds on neutrino radiative decays.

Reactor Axion (PRD-07): Improved laboratory limits axion mass 102-106 eV

Exclude DFSZ/KSVZ Models for axion mass 104-106 eV

On-Going – measurements of neutrino-electron scattering cross-sections (i.e. sin2w at MeV)

Future – develop 100 eV threshold + 1 kg mass detector for First observation of neutrino-nucleus coherent scattering Dark matter searches for WIMP-mass less then 10 GeV Improvement of neutrino magnetic moment sensitivities

29 SummarySummary

Precisely measuring 13 is one of the highest priority in neutrino oscillation study. Sensitivity to sin2213 < 0.01 is achievable based on experiences of past reactor neutrino experiments.

Four theta13 experiments are in progress. Three of them project similar timeline, full operation starting in 2010. Double Chooz will get 0.06 before 2010 using a single far detector.

Luminosity in 3 year (ton·GW·y)

Overburdennear/far (mw

e)

Projected Sensitivity

Projected Full operation date

Daya Bay 4200 270/950 <0.01 End of 2010

Double Chooz 210 80/300 0.02~0.03 2010

RENO 740 90/440 ~0.02 Early 2010 Limit on neutrino magnetic moment is improved to be < 7.4 X 10-11 B by

TEXONO. Many interesting physics topics can be carried out at very near neutrino scattering experiment.

Thanks!