KamLAND

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KamLAND (future plans)
Yuri Kamyshkov University of Tennessee for
KamLAND Collaboration April 16, 2004 _at_ SAGENAP
meeting
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Unique feature of KamLAND is a combination of

• Low detection threshold
• ? Large mass 1,000 ton of Liquid Scintillator (
  CH2)
• ? Good energy resolution lt 7/sqrt(E_MeV)
• ? Position reconstruction accuracy in x,y,z lt
  30 cm/sqrt(E_MeV)
• ? Low background due to 2700 mwe buffer
  shield veto-shield
• Rn shield pure materials LS purification
  low contamination

Recent experimental efforts (Chooz, Palo
Verde, and KamLAND) were called a
revolution in reactor antineutrino
detection (L. Mikaelyan _at_ NANP2000)
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Cleanliness and high purity of all construction
materials! Few hundred materials were radio
assayed.
Radiopurity in KamLAND
Initial Proposal Measured
Goal U lt10?14
(3.5?0.5)?10?18 g/g Th lt10?14
(5.2?0.8)?10?17 g/g K lt10?15 lt
2.7?10?16 g/g
Liquid scintillator mixing/purification plant
Following the purification techniques developed
by Borexino the U and Th contaminations were
removed from LS below analytically detectable
level of 10?15 g/g
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(No Transcript)
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Products of
Reactor anti-nu trigger threshold
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With unique and successfully operating detector
we see our challenges in ultimate improvement
and refinement of the instrument to produce most
precise and reliable data and to reach where
other experiments can not reach
Direction of improvement efforts

• ? Better understanding and improvement of
  systematic errors
• fiducial volume ? new 4? calibration system
• nonlinearity of visible energy ? RD on
  Cherenkov and Birks effects
• system stability ? calibrations with
  rad.sources new HV supplies
• ? Detection of chains of low-energy time and
  space correlated events
• ? Maintaining high detector active live time
• ? Understanding of residual radioactive and
• (0.3 Hz) muon spallation backgrounds
• ? Major improvement in radiopurity of Liquid
  Scintillator (Phase II)

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Physics with present and improved detector
? First KamLAND publication Phys.Rev.Lett.9002
1802,2003 ? high-accuracy high-statistics
reactor ?e flux, spectrum shape, flux-time
variation ? precision values for ?m2 and
improvement for ?12 ? Measurement of
terrestrial antineutrinos (lt 2.5 MeV) ? Search
for geo-reactor (2.6 8 MeV) ? Search for solar
antineutrinos ( 8-16 MeV) Phys. Rev. Lett.
92071301,2004 ? Search for relic supernova
antineutrinos (20-40 MeV) ? Search for baryon
instability (neutron disappearance from 12C) ?
Supernova watch (supernova trigger is active with
gt 95 live time) ? After improved LS
purification detection of solar 7Be neutrinos

(Phase II of KamLAND project)
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Search for neutron disappearance in KamLAND

• ? Mode-independent limit for nucleon lifetime is
  only gt 1.6?1025 years (PDG)
• ? Most of measured NDK modes have lifetime gt
  n?1030 years
• but few exceptions
• PDG

• ? These modes and in general the neutron
  disappearance are the keys
• for improvement of mode-independent nucleon
  lifetime
• ? Disappearance of neutron or two neutrons (n
  ???? and nn ???)
• might be a manifestation of (B?L)
  non-conserving interactions needed
• for explanation of Baryon Asymmetry of
  Universe.

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Search for n and 2n disappearance
E. Kolbe Y.K., Phys.Rev.D67076007,2003
Disappearance of neutron from 12C will result in
nuclear de-excitations of 11C that will lead
to the chain of space and time correlated events
in the detector
Example of detection of n??? in KamLAND
12C(n???)11C branching 2.8 for s½
disappearance ? n
10C (fast neutron capture)
? ? 10C (3.35 MeV ?)
?10B ? (27 sec, QEC 3.65 MeV)
? 3-hit signature ? (3.35 MeV), n ( 200 ?s,
2.2 MeV), ?? (27 sec, 2?3.65 MeV) ? Will be
possible to explore in KamLAND the lifetime
limits to gt 10 30 yr for both (n???) and
(nn???)
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Detection of Supernova in KamLAND
New signatures provided by KamLAND
? 100 events for 10 kpc SN ? SN trigger
refinements ? Going to join SNEWS soon ? SN
mode will be active in reactor and solar
measu- rements (next 5 years)

• For long-term SN watch it will be
• required to upgrade the detector
• and electronics to more sophisticated
• level of automated operation and
• remote control. So far no such plans are
  developed in Collaboration.

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Detection of solar 7Be neutrino (Phase II)
? Understanding of neutrino oscillation
phenomena is not yet complete. It is important
to over-determine the oscillation parameters
by measurements and to describe all observables
where deviations might indicate a new physics.
? Real-time measurement of 7Be flux alone
(without integration with other branches) can
be performed for the first time. Uncertainty
of 7Be flux can be improved by factor 2-3.
Such a measurement will essentially contribute
in understanding of the mechanisms of Sun and
other stars. ? Alternative ideas like sterile
neutrinos hep-ph/0307266 non-standard
neutrino interactions hep-ph/0402266
decoherence hep-ph/0404014 neutrino
decay hep-ph/0305317 flavor
relaxations hep-ph/0312146 also need to
be scrutinized by measurements.
Solar neutrino fluxes as free independent
parameters with a luminosity constraint
experimental (red) and theoretical uncertainties
are added linearly (gray) here
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Detection of solar 7Be neutrino (Phase II)
? While 8B neutrino transitions in Sun are
dominated by matter (MSW) effect, sub-MeV
neutrinos from 7Be should undergo vacuum
transitions. It will be interesting to
verify that survival rate for ?e will change
from 1/3 (SNO) to 5/9. Also, there
should be no Day-Night variations for 7Be
neutrinos and we can verify that too. ?
Independent precision disappearance
measurements with ?e (all solar 7Be
KamLAND) and with anti-?e (reactor KamLAND)
is a sensitive test of CPT in neutrino
sector Bahcall,Phys. Lett.
B534120-123,2002
McKeown and Vogel, hep-ph/0402025
Schematic illustration of the survival
probability of ?e created at the solar center.
Labels are sin22? values
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Major challenge remove present radioactive
contaminations below 1 MeV
Expected 7Be counting rate 110 counts/day or
1.27 mHz for LMA-I solution,
fiducial mass 363 t ?E 280800 KeV
Presently background in this region 600
Hz. Required reduction is factor of 106 !
? 238U 3.5?????8 g/g and 232Th
5.2?????7 g/g are OK ? 85Kr (T½10.8 yr) and
39Ar (T½269 yr) are present in atmosphere
(85Kr 1.5 Bq/m3) ? 210Bi and 210Po are
products of 210Pb (T½22.3 yr) ? 222Rn ?
14C/ 12C lt 5?????8 with Q?156 keV ?
External sources can be reduced by the
fiducial cut 40K lt 2.7?????? g/g
mostly from the balloon 208Tl mostly
from the rock
A. Piepke, UA
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Rn contamination
238U - series
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Collaboration work towards higher radiopurity
detector
? Outside-air-intake system was recently
commissioned (Tohoku) Rn concentration in the
detector areas reduced by factor gt 10 ? New
mine guard lining in purification area
(Tohoku) ? New Rn free N2 supply system
(Tohoku) ? Rn sealed joints and flanges
(Tohoku) ? RD on high-sensitivity Rn detectors
(Tohoku) ? RD on purification methods (Alabama,
Tohoku ) ? Energy scale non-linearity
measurements (Tennessee, Berkeley) ? Ar, Kr, Rn
purge by Helium like in Davis Cl-Ar method
(Caltech/Berkeley) ? EDTA (Ethylene Diamine
Tetraacetic Acid) in water (Tennessee)
Purification methods tried/planned
For heavy metals like 210Pb ? Water
extraction (? 3) ? Adsorption methods
Si-gel ( ? 30) tried in batch and loop
modes, with time dependence, scaling
Hydrous TiO adsorbers on hydrophobic filters
(new ? SNO) Metal scavengers 3-propyl
functionalized silica gels ? Vacuum distillation
( ?100) ? EDTA in the water (new)
For rare gases Ar,Kr,Rn ? Purging with
ultra-pure N2 (new N2 supply system) ?
Distillation of mineral oil vacuum
degasification ( more than ? 20) ? PPO
distillation (ongoing) ? Purge with He (new)
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Further plans towards purification

• ? Several methods so far demonstrated reduction
  factor of 100
• but none alone provides required reduction
  of 106
• ? cascading and combination of different methods.
• ? We plan within a year to built a prototype
  for demonstration
• of large reduction factor.
• ? Need to develop methods of small
  contamination analysis.
• ? Talking to several chemistry experts at
  Universities, BP, NIST
• After the demonstration of sufficiently
  large factor
• Construction and engineering run 1.5
  yr
• Purification 12 yr
• Phase II measurements 35 yr

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Tank
?
Purification system for Ar, Kr, Rn, Pb
Air intake from outside
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What we might see if will succeed with
purification
Understanding of backgrounds at a new level of LS
radiopurity should give us a handle on background
subtraction
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7Be signal extraction by annual flux variation
We anticipate that 7Be flux can be measured at
the level of 15-20
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We look forward several years of interesting and
challenging physics in KamLAND