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Feb 4, 2002 KamLAND - Aspen Winter Conference
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S.Dazeley, K.Eguchi, S.Enomoto, K.Furuno, Y.Gando, J.Goldman, H.Hanada, H.Ikeda, K.Ikeda, K.Inoue, K.Ishihara, W.Ito, T.Iwamoto, H.Kinoshita, T.Kawashima, M.Koga, T.Maeda, T.Mitsui, M.Motoki, K.Nakajima, M.Nakajima, T.Nakajima, I.Nishiyama, H.Ogawa, K.Oki, T.Sakabe, I.Shimizu,
J.Shirai, F.Suekane, A.Suzuki, O.Tajima, T.Takayama, K.Tamae, H.WatanabeTohoku University
T.TaniguchiKEK
T.ChikamatsuMiyagi Gakuin Women's School
H.HiguchiTohoku-Gakuin University
Y-F.WangIHEP, Beijing
J.Busenitz, Z.Djurcic, K.McKinny, D-M.Mei, A.PiepkeUniversity of Alabama
B.Berger, R.N.Cahn, Y.D.Chan, X.Chen, S.J.Freedman, B.K.Fujikawa, K.T.Lesko, K.-B.Luk, H.Murayama, D.R.Nygren, C.E.Okada, A.W.Poon, H.M.SteinerLBNL/UC Berkeley
L.Hannelius, G.A.Horton-Smith, R.D.McKeown, J.Ritter, B.Tipton, P.VogelCalifornia Institute of Technology
C.E.LaneDrexel University
J.Learned, J.Maricic, S.Matsuno, S.PakvasaUniversity of Hawaii
S.Hatakeyama, R.C.SvobodaLouisiana State University
B.D.Dieterle, C.GregoryUniversity of New Mexico
J.Detwiler, G.Gratta, H-L.Liew, D.Murphree, N.Tolich, Y. UchidaStanford University
Y.Kamyshkov, W.Bugg, Y.Efremenko, H.Cohn, A.Weidemann, S.Berridge, M.Schram, M.Batygov, Y.NakamuraUniversity of Tennessee
L.Braeckeleer, C.Gould, C.L.HoeM.Hornish, H.Karwowski, D.Markoff, J.Messimore, K.Nakamura, R.Rohm, N.Simmons, W.TornowTUNL
The KamLAND Collaboration
Feb 4, 2002 KamLAND - Aspen Winter Conference
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KamLAND: the ultimateKamLAND: the ultimatereactor neutrino oscillation experimentreactor neutrino oscillation experiment
••1 1 ktonkton liqliq. . ScintScint. Detector. Detectorin the Kamioka cavernin the Kamioka cavern
••~1300 17” fast PMTs~1300 17” fast PMTs••~700 20” large area PMTs~700 20” large area PMTs••30% photocathode coverage30% photocathode coverage••HH22O O CerenkovCerenkov veto counterveto counter••MultiMulti--hit hit deadtimedeadtime--less less
electronicselectronics•• ∆∆mm2 2 sensitivity 7sensitivity 7∗∗ 1010--66 eVeV22
LMALMA--MSW solution MSW solution within reach within reach on the earth !on the earth !
Feb 4, 2002 KamLAND - Aspen Winter Conference
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ννee
ννee
ννee
ννee
ννee
ννee
ννee
ννeeννee
ννe e detectordetector
nucle
ar
nucle
ar
reac
tor
reac
tor
ννxx ??
LL
Look for a deficit of Look for a deficit of ννee at a distance Lat a distance L
Nuclear reactors are very intense sources of Nuclear reactors are very intense sources of ννee derivingderivingfrom betafrom beta--decay of the neutrondecay of the neutron--rich fission fragmentsrich fission fragments
NN
nn
nnnn
nnNN22
NN11
NN11 and and NN22 still have too manystill have too manyneutrons and decayneutrons and decay
NN22→N→N33+e+e--++ννee
Feb 4, 2002 KamLAND - Aspen Winter Conference
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>99.9% of >99.9% of νν areareproduced by fissions inproduced by fissions in235235U, U, 238238U, U, 239239Pu, Pu, 241241PuPu
A typical large powerA typical large powerreactor producesreactor produces3 3 GWGWthermalthermal and and
66••10102020 antineutrinos/santineutrinos/s
fissionfissionMeV
e /6/200
ν
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Complementary properties of Complementary properties of Reactors and AcceleratorsReactors and Accelerators
EEνν~few ~few MeVMeV EEνν~few ~few GeVGeV
••Can probe very smallCan probe very small∆∆mm22
••Disappearance onlyDisappearance only→ fair→ fair sinsin2222θθsensitivitysensitivity
••44ππ source source → → detector massdetector mass
grows with grows with LL22
••Good mass Good mass sensitivitysensitivityrequires requires very large very large LL
••Appearance Appearance possible possible (produce (produce µµ and and ττ))
••(More) collimated(More) collimatedbeambeam
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Particle detection at low energy rather delicate:Particle detection at low energy rather delicate:beware of backgrounds !beware of backgrounds !
ν−e
e+n
γ 8 MeV
γ511 keV
γ511 keV
+→+ + nepeν••Large(rLarge(r) cross) cross--sectionsection
••Specific signatureSpecific signature
••ee++ kinetic energy kinetic energy (<8 (<8 MeVMeV))
••2 annihilation 2 annihilation γγss(0.5 (0.5 MeVMeV))
••neutron captureneutron capture(2 to 8 (2 to 8 MeVMeV))
++ +++≅ epne mMMEE )(νNeutrino energy measuredNeutrino energy measured
from positron energyfrom positron energy
Feb 4, 2002 KamLAND - Aspen Winter Conference
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The The ννe e energy spectrumenergy spectrum
Eν (MeV)2 3 4 5 6 7 8 9 10
Calculated reactorCalculated reactorννee spectrumspectrum
(10(10--8 8 /s /s MeVMeV GWGWthth))
νe+p→n+e+
cross section(~10-42 cm2)
ννee+p→n+e+p→n+e++
cross sectioncross section(~10(~10--4242 cmcm22))
Obs
erve
d sp
ectr
umObs
erve
d sp
ectr
um(in
tera
ctions
/(in
tera
ctions
/ MeV
MeV
ton
day)
ton
day)
00
55
1010
Neutrinos with E<1.8 Neutrinos with E<1.8 MeVMeVare not detectedare not detected
Feb 4, 2002 KamLAND - Aspen Winter Conference
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The detected neutrinoThe detected neutrinorate is proportionalrate is proportionalto the reactor’s to the reactor’s thermal powerthermal power
all data
0
5
10
15
20
25
30
0 2 4 6 8 10Reactor Power (GW)
Dai
ly ν
Can
dida
tes
ChoozChooz
Feb 4, 2002 KamLAND - Aspen Winter Conference
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The neutrino oscillation experiment at The neutrino oscillation experiment at the Palo Verde Nuclear Generating Station (AZ)the Palo Verde Nuclear Generating Station (AZ)
~750 m
~750 m
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Conclusion:Conclusion:ChoozChooz and Palo Verdeand Palo Verdesaw no evidence for saw no evidence for neutrino oscillationsneutrino oscillations
involving involving ννeedown todown to 1010--33 eVeV22
→ → Atmospheric neutrino Atmospheric neutrino oscillations are oscillations are
mainly mainly ννµµ--ννττ10
-4
10-3
10-2
10-1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1sin22Θ
∆m2 (
eV2 )
SK sin22Θ13 (90% CL)
Palo Verde (Swap)
Chooz
neutrinos detectedneutrinos detectedneutrinos expectedneutrinos expected
1.01±0.04 1.01±0.04 ChoozChooz1.04±0.08 Palo Verde1.04±0.08 Palo Verde
Feb 4, 2002 KamLAND - Aspen Winter Conference
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To access the region interestingTo access the region interestingfor solar neutrino for solar neutrino ∆∆mm22<10<10--5 5 eVeV22 need >100 km baselineneed >100 km baseline
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Need to think regionally: large concentration of nuclearNeed to think regionally: large concentration of nuclearpower plants exist in Europe, eastern US and Japanpower plants exist in Europe, eastern US and Japan
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Total expected signalTotal expected signalfrom reactors: from reactors:
≈≈2 2 evev/day/day
S/N ratio S/N ratio ≈≈ 2020@ 10@ 10--1414 U, U, ThTh, , 4040KKcontamination incontamination inthe scintillatorthe scintillator
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Baseline is limited: Baseline is limited: 85.3% of signal has 85.3% of signal has
140 km < L < 344 km140 km < L < 344 km
The total electric power produced “as a The total electric power produced “as a byby--product” of the product” of the ννs is:s is:
••~60 GW or...~60 GW or...••~4% of the world’s manmade power or…~4% of the world’s manmade power or…••~20% of the world’s nuclear power~20% of the world’s nuclear power
Feb 4, 2002 KamLAND - Aspen Winter Conference
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:0/08/13 21.46
A%B
0
1
2
3
4
5
6
7
0 10 20 30 40 50 60 70
−62
Pow
er fu
x at
Kam
LAND
(10
W
/cm
)
199819941993 1995 1996 1997
Time after Apr 1993 (month)
Feb 4, 2002 KamLAND - Aspen Winter Conference
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NeutrinoNeutrinooscillations in oscillations in KamLAND couldKamLAND could
result in result in distortion ofdistortion ofthe energy the energy
spectrum alongspectrum alongwith a deficitwith a deficitof detectedof detected
eventsevents
Feb 4, 2002 KamLAND - Aspen Winter Conference
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……if oscillationsif oscillationsare detectedare detectedvery accuratevery accuratemeasurementmeasurement
possible !possible !
approximateapproximateLMAS regionLMAS region
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Mostly ruled out Mostly ruled out By most recent By most recent
SNO resultSNO result
KamLAND has a realKamLAND has a realchance of observingchance of observingoscillations in the oscillations in the
LMALMA--MSW regime !!MSW regime !!
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Since reactors produce Since reactors produce while the sunwhile the sunproduces the equivalence of solar neutrinoproduces the equivalence of solar neutrinooscillations with what can be observed with oscillations with what can be observed with the KamLAND reactor experiment rests onthe KamLAND reactor experiment rests onthe validity of CPT (see B. the validity of CPT (see B. KayserKayser’’ss talk)talk)
An unexpected oscillation pattern in An unexpected oscillation pattern in KamLAND could be an indication of KamLAND could be an indication of
CPT violationCPT violation
eνeν
Feb 4, 2002 KamLAND - Aspen Winter Conference
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In addition KamLAND is a In addition KamLAND is a scalable scalable detectordetectorA possible future physics topic is the detection of BeA possible future physics topic is the detection of Be77
neutrinos from the sun… if backgrounds will allow thisneutrinos from the sun… if backgrounds will allow thisEvery effort has been made to preserve this possibilityEvery effort has been made to preserve this possibility
and during reactor neutrino running we will and during reactor neutrino running we will learn how large backgrounds for singles arelearn how large backgrounds for singles are
Other physics topics include:Other physics topics include:••Terrestrial neutrinosTerrestrial neutrinos••SupernovaeSupernovae••Solar antiSolar anti--neutrinosneutrinos••Exotic nucleon decay modesExotic nucleon decay modes
Feb 4, 2002 KamLAND - Aspen Winter Conference
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KamLAND construction timelineKamLAND construction timeline
••Summer 2000 PMT installationSummer 2000 PMT installation••Winter 2000Winter 2000--01 Veto counter installation01 Veto counter installation••Feb 2001 Balloon insertionFeb 2001 Balloon insertion••MarMar--Apr 2001 Balloon inflation and testApr 2001 Balloon inflation and test••AprApr--May 2001 Plumbing for fillMay 2001 Plumbing for fill••JunJun--Sept 2001 Fill MO and LSSept 2001 Fill MO and LS••AugAug--Sept 2001 Eng. runs with Macro Elec.Sept 2001 Eng. runs with Macro Elec.••Sept 2001 FEE/DAQ/Trigger int. (LBL)Sept 2001 FEE/DAQ/Trigger int. (LBL)••end Sept 2001 First data taking with FEEend Sept 2001 First data taking with FEE••Jan 22, 2002 Begin Data TakingJan 22, 2002 Begin Data Taking
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Cleaning the KamLAND sphere (Summer 2000)Cleaning the KamLAND sphere (Summer 2000)
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Installing 17” and 20” PMTs in KamLAND (Summer 2000)Installing 17” and 20” PMTs in KamLAND (Summer 2000)
Feb 4, 2002 KamLAND - Aspen Winter Conference
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KamLANDersKamLANDers hard at work (Summer 2000)hard at work (Summer 2000)
Feb 4, 2002 KamLAND - Aspen Winter Conference
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The completed detector, looking upThe completed detector, looking up
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Balloon installed (Apr 2001)Balloon installed (Apr 2001)
Feb 4, 2002 KamLAND - Aspen Winter Conf. 29Rece
iving
a Re
ceiving
a pa
raff
ine
para
ffine
load
in
the
mine
load
in
the
mine
““Danger”Danger”
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Scintillator is a blend ofScintillator is a blend of20% 20% pseudocumenepseudocumene and and 80% 80% paraffineparaffine oil.oil.
Different density Different density paraffinesparaffines are usedare usedto obtain the same to obtain the same density inside and out density inside and out of the balloon.of the balloon.
PPO concentration is PPO concentration is 1.5 1.5 g/lg/l of the final blend.of the final blend.
During blending the liquids During blending the liquids are preare pre--purified.purified.
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Liqu
i d le v
e l in
KamL A
ND o
n Se
p t 1
1, 0
1Liqu
i d le v
e l in
KamL A
ND o
n Se
p t 1
1, 0
1
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Have full waveformHave full waveformdigitizers on everydigitizers on everycentral and veto central and veto
channelchannel
Very important for Very important for exploring new physicsexploring new physicsand reject complex and reject complex
background signatures background signatures
Signals from blue LEDSignals from blue LEDflashers in the detectorflashers in the detector
1 1 p.ep.e..
2 2 p.ep.e..
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Very good quality Very good quality single photoelectronsingle photoelectronpeakpeak
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Initial 17” PMTs gain resultsInitial 17” PMTs gain resultsusing using s.p.es.p.e..
Gain peaks ~0.9Gain peaks ~0.9∗∗ 101077
10% low respect to the10% low respect to thecalibration done in Sendaicalibration done in Sendai
⇒⇒ reasonable: reasonable: temp = 20C Sendaitemp = 20C Sendai
10C in the 10C in the scintscint..CuBeCuBe dydy tempcotempco ~ ~ ––0.001/C0.001/Cfor 11 for 11 dydy 9.999.991111 = 0.89= 0.89
First run using the First run using the magfieldmagfield comp. coils: comp. coils: good comp. (earthgood comp. (earthmagfieldmagfield effect up effect up to 50%)to 50%)
Feb 4, 2002 KamLAND - Aspen Winter Conference
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So… what does an event look like ?So… what does an event look like ?
Time: Time: RedRed soon, soon, Blue Blue latelate Charge: Charge: RedRed alotalot, , BlueBlue littlelittle
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Radioactive and otherRadioactive and othersources can be insertedsources can be insertedin the central detectorin the central detectorusing a special accessusing a special accessport in the chimneyport in the chimneynormally closed by a normally closed by a set of gate valvesset of gate valves
A glove box inside a A glove box inside a clean room is used toclean room is used toperform this operationperform this operation
Feb 4, 2002 KamLAND - Aspen Winter Conference
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6565Zn : Zn : a 1.115 a 1.115 MeVMeV ininthe detectorthe detector
σσ//E = 6.5 %E = 6.5 %
Light YieldLight Yield241 241 p.e./MeVp.e./MeV
Prelim
inary
Feb 4, 2002 KamLAND - Aspen Winter Conference
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σσ//E = 4.2%E = 4.2%
6060Co : Co : a 2.824 a 2.824 MeVMeV ininthe detectorthe detector
Light YieldLight Yield239 239 p.e./MeVp.e./MeV
Prelim
inary
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Using E cal. Using E cal. from previousfrom previousslide the peakslide the peakis here atis here at≈≈ 2.3 2.3 MeVMeV
nn--capture in capture in hydrogen giveshydrogen gives2.2 2.2 MeVMeV
Now find cosmic ray Now find cosmic ray muonsmuons traversing the detectortraversing the detectorand look for energy deposits following themand look for energy deposits following them
Prelim
inary
Feb 4, 2002 KamLAND - Aspen Winter Conference
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Prompt Prompt –– delayed correlation time distributeddelayed correlation time distributedas an exponential with 189as an exponential with 189±±19 19 µµss
MC expectation for neutron capture is 180 MC expectation for neutron capture is 180 µµss
Prelim
inary
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