KamLAND Koji Ishidoshiro (Tohoku University) for KamLAND - - PowerPoint PPT Presentation

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KamLAND Koji Ishidoshiro (Tohoku University) for KamLAND - - PowerPoint PPT Presentation

Feb 24, 2023 159 likes •756 views

KamLAND Koji Ishidoshiro (Tohoku University) for KamLAND collaboration The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors KamLAND collaboration University of Hida, Japan 46 scientists 11 institutes,

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KamLAND

Koji Ishidoshiro (Tohoku University) for KamLAND collaboration

The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

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KamLAND collaboration

Tohoku university University of Tokyo Osaka university University of Alabama Berkeley Colorado State University Hawaii University University of Tennessee University of Washington North Carolina Central University NIKEF

11 institutes, 46 scientists

Hida, Japan March 2013

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Contents

  • KamLAND detector
  • Latest results
  • Next challenges
  • Summary

Note: KamLAND-Zen will be presented in after noon session and poser session.

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KamLAND detector

The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

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KamLAND

Kamioka Liquied scintillator Anti-Neutrino Detector (since 2002)

  • 1,000 t liquid scintillator

Dodecan (80%), Psedocumene (20%), PPO (1.36g/l)

  • 1,325 17inch + 554 20inch PMTs

Outer detector (for muon veto)

  • 3.2kton water cherenkov detector
  • ~100 20inch PMTs
  • 1,000 m depth (Kamioka mine)

Φ13m balloon

(125 um thickness)

Φ18 stainless tank

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KamLAND

Anti-neutrino detection: delayed coincidence measurement

¯ νe

p

n n p

d

γ (2.2 MeV)

e+

e−

γ (511 keV) γ (511 keV)

prompt delayed

  • time-spatial correlated events
  • Reduction of background events
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KamLAND

The world cleanest detector

238U 3.5x10-18g/g 232Th 5.2x10-17g/g

Ions are billion time more solvable to water. Wash scintillator with pure water. It is trillion times cleaner than ordinary material

  • r 100 times cleaner than Super-Kamiokande.
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Targets of KamLAND

Largest anti-neutrino detector with ultimate low background. Different neutrino physics in a wide energy range

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History of KamLAND

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Latest results

The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Reactor neutrino Geo-neutrino

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Anti-neutrino flux in Kamioka

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Expected spectrum

Normal-reactor phase Low-reactor phase

2 4 6 8 2 4 6 8

Neutrino energy[Mev]

“Reactor on-off” study for neutrino

  • scillation and geo-neutrino analysis
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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Observed spectrum

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

L/E plot

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Oscillation analysis

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Geo-neutrino

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Motivation of geo-neutrino

componential analysis of chondrite meteorite (Indirect measurement)

Why ?

Geo-neutrino can directly test radiogenic heat production and the BSE model(s).

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Results of geo-neutrino

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Comparison with Models

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Next challenges

The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

PreSN neutrino Proton decay Future projects

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PreSN neutrino

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Emitted neutrinos in Si burning phase before core-collapse supernova

PreSN neutrino

ACTA PHYSICA POLONOCA B 40, 3063 (2009)

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PreSN neutrino

ACTA PHYSICA POLONOCA B 40, 3063 (2009)

Emitted neutrinos in Si burning phase before core-collapse supernova

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Flux of PreSN neutrino

AIP Conference Proceedings 944, 109 (2007)

3h 6h 12h 24h 48h

Energy is low !!

Only high energy tail (>1.8MeV) is detectable

Nearby events

inverse-beta threshold (1.8MeV)

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Candidates

Nearby supergiants

Red supergiants

  • Antares (170pc)
  • Betelgeuse (200pc)

Wolf-Rayer star

  • Gamma Velorum (340pc)
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No oscillation Normal Inverted

Evis [MeV] Arbitary unit [/0.2MeV]

Expected spectrum

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Expected values

48-24h 24-3h 3-0h Time 1.6 6.1 9.2 Normal 0.7 2.9 4.4 Inverted

Number of events

Model: Betelgeuse like star with d=200pc

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Expected values

48-24h 24-3h 3-0h Time 1.6 6.1 9.2 Normal 0.7 2.9 4.4 Inverted

Number of events

48-24h 24-3h 3-0h Efficiency 50% 98% 99.6% Normal Efficiency 19% 80% 93% Inverted

False rate/yr

1.7 1.3 0.032

Detection efficiency (with present background level)

Model: Betelgeuse like star with d=200pc

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Expected values

48-24h 24-3h 3-0h Time 1.6 6.1 9.2 Normal 0.7 2.9 4.4 Inverted

Number of events

48-24h 24-3h 3-0h Efficiency 31% 95% 99.9% Normal Efficiency 9.4% 62% 94% Inverted

False rate/yr

2.4 1.6 0.38

Detection efficiency (reactor on)

Model: Betelgeuse like star with d=200pc

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Very early alarm

Large uncertainty of detection efficiency:

  • reactor status
  • neutrino mass hierarchy
  • uncertainty of distance
  • models of the stellar evolution

B e t e l g e u s e : 2 ± 5 p c

KamLAND will detect PreSN neutrinos.

Targets: Antares, Betelgeuse, and Gamma Velorum

Very early alarm (before SN neutrino)

Useful for astro committee and neutrino/GW detectors Excellent chance:

  • Measurement of optical shock wave
  • Study on the final stage of the stellar evolution

We are developing the alarm system.

Not miss neutrino/GW from SN

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Proton decay

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Proton decay

KamLAND (and scintillator experiment):

SUSY SO(10): p → K+¯

ν

τ ∼ 1032 − 1034

with

  • Water Cherenkov detector

: below the Cherenkov threshold (253MeV)

K+

sensitive to

K+

Indirect measurement (efficiency ~5%): 5.9x1033yr

yr

decay channel

K+ K+ → µ+νµ K+ → π0π+

(63.54%) (20.68%)

  • KamLAND is searching for with higher efficiency.

p → K+¯ ν

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Features of signal

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Features of signal

Prompt (double pulse) event Delayed event Asymmetry of 1st and 2nd peak

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Simulation of double pulse fitting

1st pulse + 2nd pulse 1st pulse 2nd pulse

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MC simulation (efficiency)

V e r y P r e l i m i n a r y

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Life time

C

  • m

i n g s

  • n

! !

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Future projects

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Future projects

75kCi 144Ce

CeLAND

4th neutrino search Ce source in KamLAND

KamLAND-Pico

Dark matter search NaI in KamLAND Check DAMA result

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Summary

The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

KamLAND: the largest anti-neutrino detector Latest results Including reactor-off period

  • Improvements of oscillation parameter
  • Geo-neutrino measurement with low background

Next challenges

  • PreSN monitor system
  • Proton decay (K+v)
  • CeLAND (4th neutrino)
  • KamLAND-Pico (dark matter)
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Geo-neutrino detection

Beta-decay of radioactivities (U, Th, K) in the Earth

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Energy spectrum

reactor (α, n)

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The 14th International Workshop on Next generation Nucleon Decay and Neutrino Detectors

Results of geo-neutrino

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Rate + shape + time analysis

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Expected events

AIP Conference Proceedings, 944, 109 (2009)

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Model

Betelgeuse like star Stellar evolution

Astroparticle Physics Volume 21, Issue 3, June 2004, Pages 303–313

  • Mass: 20M
  • Distance: 200pc

Oscillation

F = pF¯

νe + (1 − p)F¯ νx

p : survival probability

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Stellar evolution

ACTA PHYSICA POLONIGA B, 41, 1611 (2010)

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Statistics

200pc and low-reactor status (0.1 event/day)

48-24h 24-3h 3-0h Normal Inverted

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Detection efficiency

48-24h 24-3h 3-0h Efficiency 78%/55% >99% >99% Normal Efficiency 41%/17% 96%/89% >99% Inverted

False rate/yr

1.7/0.06 1.3/0.034 0.032

150pc and low-reactor status 150pc and normal status

48-24h 24-3h 3-0h Efficiency 42% >99% >99% Normal Efficiency 10% 81% >99% Inverted

False rate/yr

0.6 0.4 0.68

  • Final stage is OK !!
  • Early alarm is possible (efficiency > 80%)
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