Post on 14-Mar-2020
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
PASCOS 2005
Double Chooz:a double fast experiment
to measure the neutrino mixing parameter θ13
Glenn Horton-SmithKansas State University
Double Chooz collaboration
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Double Chooz collaboration(not quite up to date)
Florence Ardellier, Igor Barabanov, Steve Berridge, L.B. Bezroukov, Maurizio Bonesini, Janine Boucher, Christian Buck, William Bugg, Anatael Cabrera, Carla Cattadori, Bernard Courty, Michel Cribier, Olivier Dadoun, Ferenc Dalnoki-Veress, Nikolay Danilov, Steven Dazeley, Alain De Bellefon, Herve de Kerret, Assunta Di Vacri, Yuri
Efremenko, Alexandre Etenko, Muriel Fallot, Marianne Goeger, Maury Goodman, Christian Grieb, Arnaud Guertin, Caren Hagner, Wolfgang Hampel, Frank Hartmann, Glenn Horton-Smith, Claude Jeanney, Josef Jochum, Yuri
Kamyshkov, Jerome K. Busenitz, Thomas Kirchner, Yuri Krylov, Didier Kryn, Tobias Lachenmaier, Chuck Lane, Thierry Lasserre, Christian Lendvai, Alain Letourneau, David Lhuillier, John LoSecco, Fredecric Marie, Jacques
Martino, Igor Matchouline, Guillaume Mention, Emanuela Meroni, Bill Metcalf, Jean-Pierre Meyer, Alain Milsztajn, Dario Motta, Lothar Oberauer, Michel Obolensky, Luciano Pandola, Giancarlo Piredda, Walter Potzel, David Reyna, Andrew Sabelnikov, Stefan Schoenert, Ute Schwan, Sahbi Selmane, Hardy Simgen, Mikhail Skorokhvatov, Serguey
Soukhotine, Ion Stancu, Bob Svoboda, Jonathan Thron, Antonin Vacheret, Matthieu Vatre, Daniel Vignaud, Franz Von Feilitzsch, Evgeni Yanovich, Karim Zbiri, Raoul Zimmerman
● France: APC, DAPNIA, Subatech-Nantes● Germany: EKU-Tubengen, MPIK Heidelberg,
University of Hamburg, TUM (Munich)● Italy: INFN (Assergi & Milano), University of l'Aquila● Russia: Kurchatov Institute, RAS● USA: Alabama, ANL, Drexel, Kansas State, LSU, Notre
Dame, Tennessee
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
What I will tell you
● Some brief review● Experimental strategy, location, and some details● Sensitivity goal● Schedule
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Totally unnecessary reminder: neutrino mixing matrix
[ |e>|>|> ]=[U e1 U e2 U e3
U 1 U 2 U 3
U 1 U 2 U 3] [ |1
|2|3 > ]
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Reminder: the mixing angles
[ c12c13 ei1 /2 s12c13 e
i 2 /2 s13 e−i
−s12c23c12 s23 s13eie i1/2 c12c23−s12 s23 s13 e
i e i 2 /2 s23c13
s12 s23−c12c23 s13eie i1/2 −c12 s23s12c23 s13 e
i e i 2 /2 c23c13]≃[ 0.8 0.5 ?
−0.4 0.6 0.70.4 −0.6 0.7 ]
where cij=cos ij , sij=sin ij , is the CP-violating Dirac phase, and 1 ,2 are CP-violating Majorana phases.
θ12 = 33º±3º solar observations (SK, SNO) [+KamLAND input]
θ23 = 45º±7º atmospheric and accelerator (SK, K2K, MINOS)
θ13 < 13º reactor experiments (CHOOZ, future)sin(θ13)eiδ = ? accelerator (NOVA, T2K)
α1, α2 = ?? [neutrinoless double beta decay?]
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Reminder: what mixing does
νe
νµ
ντ
L/E (km/MeV)
KamLANDEe+ > 2.6 MeV cut
P e e=1−sin2 212 sin2 m122 L
4 E
“Solar” delta mass-squared (8.2+0.6-0.5)×10-5 eV2.
Mixing angle θ12 = 33º±3º.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Reminder: The basic strategy
Source
Neutrino detector observesrate and spectrum.
Analyze deficit or appearanceto look for oscillation.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
I just can't resist talking about KamLAND a bit
53 reactor cores, power ~3 GWth/core,at typical baseline of 180 km, provideexpected no-oscillation rate of about1 event per kiloton-day at KamLAND.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
KamLAND L0/E plotPRL 94, 081801 (2005)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
“Atmospheric” ν oscillationsP =1−sin2 223 sin2 m23
2 L4 E
13=0 case
νe
νµ
ντ
L/E (km/GeV)
Atmosph. ν,ν beams
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
1-3 oscillation modeP e e≃1−sin2 213 sin2m13
2 L4 E
, form12
2 L4 E
≪1
νe
νµ
ντ
L/E (m/MeV)
νµ beam, νe detector(NOνA, T2K)
Reactor experiment:νe “beam”, νe detector
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Cosmological relevance?● “Leptogenesis”, a possible explanation of matter-
antimatter asymmetry, requires CP violation in the neutrino sector.
● CP violation can't be found in neutrino oscillations if θ13
is non-zero.● Does this mean that if θ13 is non-zero, then we can prove
or disprove leptogenesis with NOVA or T2K?● Sadly, no: the CP violation we can probe in these
experiments is not, in general, the CP violation needed in leptogenesis. (Some do models connect the two.)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Neutrinos on trial?
“Nonetheless the observation of CP violation and neutrinoless double beta decay would provide
strong circumstantial evidence for leptogenesis...
Even though we may not be able to convict leptogenesis in a criminal trial, we may still find it
guilty in a civil case.”-APS Neutrino Study, Astrophysics and
Cosmology working group
(Gee, I didn't realize breaking matter-antimatter symmetry was a crime...)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Aside: Why do so many questions related to our origins go to court, anyway?
In the beginningthe Universe was created.
This has made a lot of people very angry and been widely
regarded as a bad move.-Douglas Adams
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Reactor antineutrino disappearance experiment
P e e≃1−sin2 213 sin2m132 L
4 E
, form12
2 L4 E
≪1
νe
L/E (m/MeV)
θ13 = 0.1sin22θ13= 0.04∆m2
13 =.0025 eV2
L=1 kmE=2~6 MeV
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
History of reactor neutrino experiments
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Current best limit from CHOOZ experiment
Sin22θ13 < 0.19 (90% CL at 2.0 10-2 eV2)
νep→e+n; Neutron/positron coincidence
200 days reactor on; 142 days reactor off
Stopped due to systematic error of reactor flux
Palo Verde
Chooz
SK allowed sin22θ13 (90% CL)
sin22θ13
∆m
2
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
The new strategy in brief
Reactor
Near detector observestrue rate and spectrumwith almost no oscillation effect.
Far detector observesrate and spectrum withoscillation effect dominatedby θ13.
Reduce the systematic errors that limited past reactor experiments (mainly neutrino absolute flux and spectrum shape) by using two detectors, one “near” and one “far” from the reactor neutrino source.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Several proposals
● KR2Det, Siberia (defunct)● Diablo Canyon, California (killed)● KASKA, Japan (never say die!)● Double Chooz, France● Braidwood, Illinois● Daya Bay, China● Angara, Brazil● Korea?
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
The Chooz site
To be built:Baseline ~ 150 mOverburden ~ 60 mwe
Ready to be used:Baseline ~ 1100 mOverburden ~ 300 mwe
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
The logo explained
Meuse river“C” “H”
Near and far detectors“OO”
νe and νx
“Z”
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
More photos of Chooz site
Chooz-near
Chooz-far
2 x 4200MW Reactors
1100m Baseline300MWE Overburden
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Improvements over CHOOZ
● Improved detector design.● New and improved scintillator.● Active inner and outer veto systems.● Near detector.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Improved detector design
Gamma catcher: scintillator with no Gd
7 m
7 m
BUFFER Mineral Oil with no scintillator
7 m
Shielding steel and external vessel(studies, réalisation, intégration IN2P3/ PCC)
Target- Gd loaded scintillator (12.3 m3)
Modular Frame to support photomultipliers (UT)
Optically separated inner veto to tag muons
Nested 3-layer design reducesdetector edge effects while maintainingoptimal shielding against external backgrounds. Target volume is actually bigger than original CHOOZ.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Acrylic Vessel Design✔ The full detector will be
3.6 m (d) x 4 m (h)
✔ 1/5th scale prototype is under construction
Deformation analysis from Saclay
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
New and improved scintillator
Degradation of the attenuation length caused trouble for CHOOZ.
After several years of research, MPI-Heidelberg has developed more optically stable Gd loaded oils: one carboxylic, one beta-diketones.
Currently producing 200 L. They will optimize this
scintillator and provide for Double Chooz. 390 420 450 480 510 540 570 600
0,040,060,080,100,120,140,160,18
abso
rban
ce
wavelength [nm]
Sep 03 Nov 03 Feb 04 Apr 04 Aug 04 Okt 04
λ
t
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Near hall conceptual design
Lnear ~100 meters, the closest near detector of any proposed experiment
Fiducial detector and gamma catcher identical to far det.~60 m.w.e. deep.Additional outer veto & larger inner veto for cosmogenic background suppression.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Active veto systemsInner veto tags muons near detector
The Outer Veto provides additional tagging of µ induced background n’s.
Prototype counters designed/tested A Fluka simulation of µ’s at the near detector is being used to specify needed coverage
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Phototubes
₪ Baseline – 1040 tubes₪ 12.9% phototube coverage₪ 190 pe/ MeV (Monte Carlo)
╬ PMT related backgrounds were about 1/3 BG at CHOOZ
╬ Recent work on• Cabling schemes• Sensitivity to B fields• Angular sensitivity• Tilting tube options• Phototube comparisons• Radioactivity measurements
╬ PMT’s must be ordered by this fall to maintain the “rapidly deployed” schedule.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Calibration systems
In the Central Target Region,an Articulated Arm provides
– Positioning Resolution/Precision
– Total Coverage
In the Gamma Catcher, wire driven sources in guide tubes can provide calibration
Articulated arm design Wire source Wire driver
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Signal
● A good number to remember for reactor neutrino experiments is ≈ 1 event/(GWth-ton-day) @ 1 km.
● Far detector is 12.3 m3, 0.8 ton/m3, 1 km from 2 cores, 4.2 GWth/core ==> ~80 events/day. (!)
● Identical near detector 100~140 m from cores, 4000~8000 events/day. (!!!)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Backgrounds
☼ Near detector overburden is chosen to keep signal/background above 100
☼ Largest background before muon tagging is fast neutrons; efficient inner and outer veto can reduce them considerably.
☼ Largest uncertainty in background comes from spallation of Li9 ☼ Backgrounds measured at CHOOZ used to calculate sensitivity
Detector Signal 9Li n n-accid. total BG S/B δB/Sfar 80 < 1.7 0.5 0.2 < 2.4 >30
±0.3 - - ±0.3 0.004near >4000 < 17 5 2 < 24 >160
±3~10 - - ±3~10 <0.003
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
γ backgrounds under control
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00
Radius, cm
Rat
e, H
z in
cm3
Scintillator γ - Catcher Veto Sand Rock
ChoozChooz
Steelγ - Catcher
DChoozDChooz
PMTs
Vessel
Acrylic
RockVetoBufferScintillator
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Systematics
<0.6%0.6%Total
<0.2%0.3%Distance Cut
0.1%0.1%Acquisition
<0.25%0.25%Dead Time (veto)
0.1%0.1%Time cut
negligiblenegligibleSpatial Effects
0.2%0.2%Neutron Energy
0.1%0.2%Neutron Efficiency
0.1%0.1%Ratio H/C
0.1%0.1%Density
0.2%0.2%Volume
0.2%0.2%Solid Angle
Double ChoozAfter CHOOZ
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Sensitivity
Original ChoozDetector ErrorDouble Chooz goal
(I will show sensitivity vs. time next)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Projected schedule:sensitivity vs. time
Far detector only
Far & Near detectorstogether
05/2007 05/2008 05/2009 05/2010
σsys=2.5%
σsys=0.6%Far detector
onlyFar & Near detectors
together
05/2007 05/2008 05/2009 05/2010
σsys=2.5%
σsys=0.6%
● Far Detector starts in 2007.● Near detector follows 16
months later.● Double Chooz can surpass
the original Chooz bound in 6 months.
● 90% C.L. contour ifsin2(2θ13)=0.
● MINOS is supposed tell us ∆m2
atm to 20% by then.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Comparison with “incomplete selection” of predictions
The nominal 90% CL sensitive region of Double-CHOOZ is shown in yellow.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Connection between reactor and accelerator experiments
● Many people have made lots of plots, but the one I like is the plot of the directly measured experimental quantities: νe appearance in the accelerator beam versus νe disappearance from the reactor flux.
● If you don't like these plots, you can find lots of others in the APS neutrino study, in any number of papers, proposals, etc., etc.
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Connection with long baseline accelerator experiments
Acc
eler
ator
-bas
ed ν
e app
eara
nce
resu
lt
Reactor-based νe disappearance result
DC 2010(+/- 0.02)
DC 2010(< 0.03)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Connection with long baseline accelerator experiments
DC 2010(+/- 0.02)
G. Horton-Smith, KSU, Double Chooz June 1, 2005, PASCOS '05
Conclusions
● Double Chooz is moving forward rapidly.● Double Chooz will make a fast measurement or
limit on θ13 to order sin22θ13 ~ 0.03.● This is a valuable contribution:– will improve knowledge of PMNS matrix;– might give “circumstantial evidence” supporting
leptogenesis;– will guide later experiments.