Summary of the workshop on Future LowEnergy Neutrino Experiments

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Summary of the workshop on Future Low-Energy
Neutrino Experiments TUM, Munich, October 9-11,
2003
Thierry Lasserre CEA/Saclay, CERN, 20/11/2003
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One nuclear plant two detectors
D1 0.1-1 km
D2 1-3 km
Nuclear reactor 1,2 core(s) ? ON/OFF ok ? 4
cores ? ON/OFF no !
Near detector 5-50 tons gt 50 mwe

• Far detector
• 5-50 tons
• gt 300 mwe

• Isotrope ?e flux (uranium plutonium fission
  fragments)
• Detection tag ?e p ? e n, ltEgt 4 MeV,
  Threshold 1.8 MeV
• Disappearance experiment suppressionshape
  distortion between the 2 detectors
• 2 IDENTICAL detectors (CHOOZ, KamLAND,
  BOREXINO/CTF type)
• Minimise the uncertainties on reactor flux
  spectrum (2 in CHOOZ)
• Cancel cross section uncertainties
• Challenge relative normalisation between the
  two detectors lt 1 !

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Groups involved in discussions

• US
• Columbia University
• Argonne National Laboratory
• Berkeley Laboratory
• The University of Chicago
• The University of Alabama
• Caltech
• Stanford University
• etc

• France
• PCC, Collège de France APC
• (Chooz, LENS, Borexino)
• CEA/Saclay
• (LENS)
• Germany
• MPI fuer Kernphysik, Heidelberg
• (Borexino, LENS ? Gd scintillator)
• TUM, Munich
• (Borexino)
• Tubingen University
• (Borexino)

• Italy
• INFN Bologna
• Japan
• Tokyo Metropolitan University
• Tohoku University
• Russia
• Kurchatov Institute

sorry for the groups I have omitted
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Detector size scale
Reactor/?13 Example 20 t ( 5 ? 50 t)
CHOOZ 5 t
Borexino 300 t
KamLAND 1000 t
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90 C.L. sensitivity if sin2(2?13)0
_at_?m22.0 10-3 eV2
sbkg sbkg sbkg
JHF
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Huber, Lindner, Schwetz Winter
hep-ph/0303232 G. Men tion T. L.
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reactor 1 (2 RNU)
reactor 2 (40 RNU)
RNU Reactor Neutrino Unit 1 RNU 1031 free H
GWth year
Reactor1 (0.5 km, 2.3 km) 13 tonsPXE x 10 GW
x 3 years ? sin2(2?13)lt0.02, 90 C.L Reactor2
(0.5 km, 2.3 km) 270 tonsPXE x 10 GW x 3 years
? sin2(2?13)lt0.01, 90 C.L
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Forthcoming ? LBL sin2(2?13)
CHOOZ-I 90 C.L
Huber, Lindner, Schwetz Winter (Theory group,
TUM)
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Next generation ? LBL sin2(2?13)
CHOOZ-I 90 C.L
Huber, Lindner, Schwetz Winter, (Theory Group,
TUM)
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Which site for the experiment ?
Penly Chooz Cruas
Byron
Kashiwasaki
Krasnoyarsk
Diablo Canyon
Taiwan
Angra
One reactor complex Two underground cavities
_at_0.1-1 km 1-2 km
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Which site for the experiment
CHOOZ
Kashiwasaki
Diablo Canyon
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The Diablo Canyon site (US)
600-800 mwe

• Close to San Francisco (500 km), California.
  Leader Group LBNL
• Two cores (2 x 3.1 GWth)
• 3 detectors D1300m , D2 0.8 1 km , D3 2
  3 km
• Horizontal tunnel gt1.5 km with 300 ? 800 mwe
  overburden
• Status negotiation with the power plant
  underway (permit, safety , ecology )
• Partial approval from PGE to proceed with
  geological studies
• Tunnel labs 2 movable detectors (50-100 tons)
  to be constructed simultaneously
• Data taking ? end 2007 ? Cost 50 M
• sin2(2?13)lt0.01-0.02 _at_90 C.L

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The Kashiwasaki site (Japan)
Kashiwasaki power plant 24.3 GWth 7 cores ?
2 near detectors needed !
Leading group Tohoku Univ. (Suekane_san
Inoue_san)
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The Kashiwasaki site (Japan)

• Kashiwasaki power plant 24.3 GWth
• 7 cores ? 2 near detectors needed !
• D1300-400 m , D2 1.3 km
• 3 identical detector of 8 tons
• ? 3 shafts (12 M, 15 months)
• Near detectors _at_100 mwe
• Far detectors _at_500 mwe
• Data taking 2007-2008 Cost lt20 M

Sensitivity (3 years) sin2(2?13)lt0.026 _at_90 C.L
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The Chooz site, Ardennes, France
Double-CH?13?13Z
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The Chooz site
Near site D100-200 m, overburden 50-80 mwe Far
site D1.1 km, overburden 300 mwe former
experimental hall
2x11.5 tons, D1100-200m, D21050m. Sensitivity
3 years ? sin2(2?13) lt 0.03
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CHOOZ-Far ready to be used again!
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CHOOZ-Far detector (12.7m3 fiducial, preliminary)
3.5 m
CHOOZ-I pit
7 m
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CHOOZ-Near
250 m
125 m
A few locations under study, but enough space in
any case
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CHOOZ-Near new Laboratory
10-15 m
Dense material
5- 15 m
Other possibility bloc of concrete (d2.4) piled
up !
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Status of the discussions with EDF

• CHOOZ site has been secured.
• -Strong support for the CHOOZ nuclear plant

• Far site 1.1 km 300 mwe
• -Existing laboratory
• -Available (7x7 m tank of CHOOZ-I)

• Near site 100-200 m
• -Underground detector man-made overburden
• -Feasibility confirmed by the power plant staff
• -50 to 80 mwe required
• -Civil engineering study will start soon
• (done financed by EDF )

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The experimental challenge

Relative error between Near/Far detector lt 0.8
seems possible still under study
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Sensitivity to sin2(2?13)
sin2(2?13) _at_90 C.L
sbkg near 1 far 0.5 sbkg near
1 far 1 sbkg near 2 far 1
_at_?m2atm2.0 10-3 eV2
years
1 0.75
2 1.5
3 2.25
4 (pure PXE) 3.0 (PXE/PC mineral oil)
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DNear
0.1 km NumberOfFreeProtonsNear
1.8944e29 (11.5 tons PXE) DFar
1.05
km NumberOfFreeProtonsFar
3.7888e29 (11.5 tons PXE) Global
normalisation Fit is ON
with an error of 2 Relative normalisation
Fit of Near/Far Detector is ON with an
error of 0.06 Shape Error Fit is
ON with an error of 2
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Summary outlook _at_Double-CHOOZ

• Support for the EDF power company to do a 2nd
  experiment _at_CHOOZ
• Reactor potential _at_CHOOZ sin2(2?13)lt0.03, 90
  C.L. (?m2 2.0 10-3 eV2)
• Current limint CHOOZ sin2(2?13)lt0.2 ?
  discovery potential !
• Technology / design well known (Chooz-I,
  Borexino, KamLAND, )
• ? few RD needed Gd loading (stability)
  material compatibility
• ? RD in Saclay material compatibility
  mechanical constraint scint. test
• Case under study French ? target vessels
  German scintillator (MPIK)
• Experiment cost, Double-CHOOZ case
• 2 x 15 tons, cost detectors lt10 Meuros. (
  Civil engineering)
• Our Goal _at_CHOOZ Construction starts in 2005 (
  civil engineering )
• Start data taking in
  2007-2008

year
2004
2005
2006
2007
2008
2009
2003
Site
Data taking
Prop.
Construction ?
design
Construction ?
lt sin2(2?13) lt 0.025-003
lt sin2(2?13) lt 0.04