KamLAND Future Prospects

Atsuto Suzuki

Tohoku University

KamLAND　Collaboration

III Int. Workshop on Neutrino Oscillations in Venice III Int. Workshop on Neutrino Oscillations in Venice Feb. 7-10, 2006Feb. 7-10, 2006

1. KamLAND-II

2. Prospects of Solar Neutrino Detection

3. Toward Precise Measurement of

Reactor Neutrinos

4. More and more Geoneutrinos

5. Conclusions

1. KamLAND-II

2. Prospects of Solar Neutrino Detection

3. Toward Precise Measurement of

Reactor Neutrinos

4. More and more Geoneutrinos

5. Conclusions

OutlineOutline

180 km

300

1. KamLAND-II (summer in 2006) 1. KamLAND-II (summer in 2006) 1. KamLAND-II (summer in 2006) 1. KamLAND-II (summer in 2006)

※※ 77Be solar neutrino detection:Be solar neutrino detection: JSPS 5-year project from 2004JSPS 5-year project from 2004※※ Precise measurements of reactor-, geo- and solar neutrinos:Precise measurements of reactor-, geo- and solar neutrinos: MEXT 5-year project from 2005MEXT 5-year project from 2005

KamLAND-IIKamLAND-II

2. Prospects of Solar Neutrino Detection2. Prospects of Solar Neutrino Detection2. Prospects of Solar Neutrino Detection2. Prospects of Solar Neutrino Detection

single events in KamLAND

10-5 ~ 10-6

distillation　test bench

212212PbPb

222222RnRn R~10R~10-2-2

N2 purge　test bench

222222Rn : Rn : 4x104x10-3-3 >R > 5x10 >R > 5x10-4-4

8585Kr :Kr : 4x104x10-5 -5 >R > 5x10>R > 5x10-6-6

Test Bench StudiesTest Bench StudiesTest Bench StudiesTest Bench Studies

Background Reduction StatusBackground Reduction StatusBackground Reduction StatusBackground Reduction Status

purification system purification system installation :installation :until this Julyuntil this July

purification system purification system installation :installation :until this Julyuntil this July

space for new purification system(May 2005)

238U232Th 40K 85Kr210Pb

(3.5 ± 0.5) x 10-18 g/g(5.2 ± 0.8) x 10-17 g/g< 2.7 x 10-16 g/g~ 1 Bq/m3

~ 10-20 g/g

10-16 g/g 10-16 g/g 10-18 g/g~1 Bq/m3

~10-25 g/g

impurities present goal reduction

OK OK 10-2

10-6

10-5

distillation purge

< 10-2

< 10-5

< 10-4

< 10-5

100 days data100 days data

events (0.3 <E< 0.8 MeV) / day / fid. (R< 4m)events (0.3 <E< 0.8 MeV) / day / fid. (R< 4m)77Be (80) , CNO (16), pep (4) , Be (80) , CNO (16), pep (4) ,

8585Kr (8), Kr (8), 210210Bi (<2), Bi (<2), 210210Po (<1), Po (<1), 4040K (3)K (3)

Expected Energy Spectrum in KamLAND-Expected Energy Spectrum in KamLAND-IIII

Expected Energy Spectrum in KamLAND-Expected Energy Spectrum in KamLAND-IIII

210Po210Po 85Kr85Kr

events (0.3 <E< 0.8 MeV)/ day / fid. (R < 4m)events (0.3 <E< 0.8 MeV)/ day / fid. (R < 4m) 77Be (80) , CNO (16), pep (4) , Be (80) , CNO (16), pep (4) ,

8585Kr (8), Kr (8), 210210Bi (<2), Bi (<2), 210210Po (<1), Po (<1), 4040K (3)K (3)

Seasonal Flux Variation of Solar Seasonal Flux Variation of Solar NeutrinosNeutrinos

Seasonal Flux Variation of Solar Seasonal Flux Variation of Solar NeutrinosNeutrinos

3 years data in KamLAND-II3 years data in KamLAND-II

Possibility to Detect CNO and pep Possibility to Detect CNO and pep NeutrinosNeutrinos

Possibility to Detect CNO and pep Possibility to Detect CNO and pep NeutrinosNeutrinos

CNO+pepCNO+pepCNO+pepCNO+pep

RR

tt

energyenergy

Present KamLAND DataPresent KamLAND Data

100 200 (min.)

1.2 1.4 1.6 1.8 (MeV)

200 800 (cm)400 600

1111C IdentificationC Identification1111C IdentificationC Identification

L < 50 cm along L < 50 cm along

# of neutrons > 0# of neutrons > 01111C with C with R < 150 cmR < 150 cm

((R : distance from the nearest nR : distance from the nearest n))

New Electronics for IdentifyingNew Electronics for IdentifyingSuccessive Multiple EventsSuccessive Multiple Events

New Electronics for IdentifyingNew Electronics for IdentifyingSuccessive Multiple EventsSuccessive Multiple Events

new (dead-time free)

Expected Energy Spectrum inExpected Energy Spectrum inCNO+pep RegionCNO+pep Region

Expected Energy Spectrum inExpected Energy Spectrum inCNO+pep RegionCNO+pep Region

1111CCCNOCNOpeppep

7Be7Be

3 years data3 years data

90% rejection of 90% rejection of 1111CC90% rejection of 90% rejection of 1111CC

7Be7Be

CNOCNO

peppep

background subtractedbackground subtracted

neutron tagging efficiencyneutron tagging efficiency ~ 100%~ 100%

3 years data3 years data

3. Toward Precise Measurement of 3. Toward Precise Measurement of Reactor NeutrinosReactor Neutrinos

3. Toward Precise Measurement of 3. Toward Precise Measurement of Reactor NeutrinosReactor Neutrinos

shape-analysis

LMA II: disfavoredat 98.0% CL

LAM 0: disfavoredat 97.5% CL

Nobs – NBG

Nexpected

= 0.686 ± 0.044 (stat) ± 0.045 (syst)

disappearance:99.995 % CL

ee xx : 2-flavor case : 2-flavor case

LAM I

68Ge : 1.012 MeV (+) 65Zn : 1.116 MeV ()60Co : 2.506 MeV ( + ) AmBe : 2.20 , 4.40, 7.6 MeV

n

12N, 12B,…

Improvement of Detector Systematic Improvement of Detector Systematic ErrorError

Improvement of Detector Systematic Improvement of Detector Systematic ErrorError

energy scale, timing, detection,

n capture time, n detection,

trigger efficiency, light transport,….

radioactive sources, laser system, LEDs,

cosmic-ray , –induced spallation products

Off-Axis Calibration System

6.5 % 6.5 % 4 % 4 %total uncertaintytotal uncertainty

Setting Off-Axis SystemSetting Off-Axis System

statistics x 5statistics x 5 statistics x 10statistics x 10limit due tolimit due to

4% systematic error4% systematic error

statistics x 5systematic error : 4%

statistics x 10systematic error : 4%

Updated Oscillation ParametersUpdated Oscillation ParametersUpdated Oscillation ParametersUpdated Oscillation Parameters

ee

ee

ee ee

ee

G. Gamow: 1953

4. More and More 4. More and More GeoneutrinosGeoneutrinos

4. More and More 4. More and More GeoneutrinosGeoneutrinos

Antineutrino Energy (MeV)Antineutrino Energy (MeV)

Eve

nts

/0.1

7 M

eVE

ven

ts/0

.17

MeV

2.382.38

±0.01±0.01Accidental Accidental Coincidence Coincidence

# of # of eventseventsBackgroundBackground

127 127 ±13±13TotalTotal

best best fitfit

80.480.4

±7.2±7.2

1.9 1.9 ±0.2±0.2

Reactor Reactor ee

short livedshort lived

long livedlong lived

42 42 ±11±11

1313C (C (,n,n) ) 1616OO

signal 152

KamLANDKamLAND

ThTh UU

Geoneutrino Result in Geoneutrino Result in KamLANDKamLAND

Geoneutrino Result in Geoneutrino Result in KamLANDKamLAND

2 years data in KamLAND-II2 years data in KamLAND-II

best fitbest fit

(NU – NTh)/(NU + NTh)

NU +

NT

h

CL 68.3%CL 95.4%CL 99.7%

best fitbest fit

Th/U~3.9Th/U~3.9Th/U~3.9Th/U~3.9

BSE modelBSE modelBSE modelBSE model

Constraints on Uh & U /Th

in KamLAND-II

Constraints on Uh & U /Th

in KamLAND-II

Th/U~3.9Th/U~3.9Th/U~3.9Th/U~3.9

2 years data in KamLAND-II2 years data in KamLAND-II

ConclusionsConclusions

KamLAND-II providesKamLAND-II provides

• high rate detection of high rate detection of 77Be solar neutrinos,Be solar neutrinos,

• chance to detect CNO + pep solar neutrinos,chance to detect CNO + pep solar neutrinos,

• stringent constraint on stringent constraint on mm22 for reactor neutrinos, for reactor neutrinos,

• more constraint on U+Th (geoneutrinos),more constraint on U+Th (geoneutrinos),

andand

• interesting test of U/Th (geoneutrinos) interesting test of U/Th (geoneutrinos)