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TAUP 2007R. Plunkett14 September,2007
Status of the NOvA Experiment
Robert PlunkettFermi National Accelerator Laboratory
Batavia, IL, USA
TAUP 2007Topics on Underground and Astroparticle Physics
14 September 2007
TAUP 2007R. Plunkett14 September,2007The NOvA Collaboration
25 Institutions, 129 Physicists and EngineersArgonne, Athens, Caltech, College de France, Fermilab, Harvard, Indiana, ITEP-
Moscow, Michigan State, Minnesota, Minnesota-Duluth, Munich, Northern Illinois, Ohio State, Rio de Janeiro, South Carolina, Southern Methodist University,
Stanford, Stonybrook, Texas, Texas A&M, Tufts, UCLA, Virginia, William and Mary
TAUP 2007R. Plunkett14 September,2007
Located 30 km south of CanadaImproved road access planned
810 km baseline14.6 mrad off-axis
Ash River Site for NOvA
TAUP 2007R. Plunkett14 September,2007NuMI Tunnels and Facility
p beam
Pion beam
250 m
NuMI Components in Main Injector
NuMI Pretarget Area
TAUP 2007R. Plunkett14 September,2007 Existing NuMI Neutrino Beam
207m
•120 GeV protons strike the graphite target
• Nominal Intensity 2.4x1013 ppp with ~2 sec cycle time.
• Initial intensity ~2.5 x 1020 protons/year
• Ultimate intensity ~ 3.4 x 1020 protons/year (2008-9)
Horn and Stripline
TAUP 2007R. Plunkett14 September,2007Upgrades to NuMI for NOvA
Reconfigure horns for higher energy optimum.
Increase beam power by use of Recycler (1.3 s cycling).
New target system for higher intensity
NOvA beam choice
TAUP 2007R. Plunkett14 September,2007
Expected evolution of proton intensity
Achieved!
Expected after current shutdown
Requires use of recycler storage ring after Tevatron shutdown
Possible upgrade
path
TAUP 2007R. Plunkett14 September,2007
Graphical Representation of Off-Axis Beam
Length of this vector very insensitve to pion
0
lab
TL
PP
At ~ /2 PT 0 as vary *
Flux peaks in desired region
TAUP 2007R. Plunkett14 September,2007
Off-axis provides improved background levels
Fig. 2.8: Simulated energy distributions for the e oscillation signal, intrinsic beam e events, neutral-current events and charged-current events with and without oscillations. The simulation used m2
32 = 2.5 x 10-3 eV2, sin2(2 23) = 1.0, and sin2(2 13) = 0.04. An off-axis distance of 12 km at 810 km was assumed.
NC at low energy because no high energy tail
Beam e are spread out over a wide
range - remove by windowing
Backgrounds show a different energy
spectrum and can be removed during
analysis
TAUP 2007R. Plunkett14 September,2007
•Far - 18 kT reference design, 12 x 12 modules, 1178 layers
•Near - 218 T, 2 x 3 modules, 199 layers, muon ranger at end
•Integration-prototype Near - 88 T, 2 x 3 modules, 124 layers, start in 2008
Three NOvA Detectors
TAUP 2007R. Plunkett14 September,2007
NOvA Building a considerable structure
19 m
107 m
Pulsed beam allows surface construction.Overburden of 1.2m concrete, and 30 cm Barite reduces C.R. backgrounds (especially to low levels
Block assembly area
TAUP 2007R. Plunkett14 September,2007
Construction in Subsections for Structural Stability
31-planeblock
1-cm expan-sion gap
31-planeblock
Block pivoter raises 127 Ton blocks
Each block has ~6000 channelsFilling proceeds as blocks constructedDetailed mechanical analysis for stability against bulge, creep.
TAUP 2007R. Plunkett14 September,2007
Extruded PVC tubes filled with liquid scintillator
To 1 APD pixel
typicalchargedparticle
path
L
To 1 APD pixel
typicalchargedparticle
path
L
6 cm
4 cm
60 cm
6 cm
4 cm
60 cm
6 cm
4 cm
60 cm
6 cm
4 cm
60 cm
~ 16 m
Prototype with full-length fiberReadout cosmic muons
TAUP 2007R. Plunkett14 September,2007
Constructed from modular extrusions
Liquid scintillator (14.8M liters, 12.6 ktons)
Contained in 3.9 x 6.6 cell cells of length 15.7 m
18 m attenuation length5.5% pseudocumene
Extruded PVC (5.4 ktons)
15% anatase TiO2 for high reflectivity
Wavelength shifting fiber (18k km)
0.7 mm diameter Looped, both ends to same readout
pixel
TAUP 2007R. Plunkett14 September,2007
Extrusion Structure and Initial Production
16 Cell extrusions – ready for further assembly
15.8 m in length is long.
TAUP 2007R. Plunkett14 September,2007NOvA HPD Detector Electronics
QE ~85%, gain ~100QE well-matched to fiber spectrum
Cooled by thermoelectric cooler to -15 CUntriggered continuous digitization
APD on prototype carrier board
Emission Spectra and Q.E. Water cooling for TEC’s
TAUP 2007R. Plunkett14 September,2007
MINOS underground area allows a Near Detector
target volume
veto
shower containment
muon ranger
218 tons total / 20 tons fiducial
At low 13, reducing uncertainty on background at far detector can increase sensitivity by even more than additional exposure
TAUP 2007R. Plunkett14 September,2007Electron Identification for NOvA
>20 variables in Neural Net
Examples shown – other variables study charge-range distributions
Overall efficiency ~30% (optimizable)
Neural Net Output
signal
signal
signal
bkg.
NC
NC
CC
CC
CC
beam e
TAUP 2007R. Plunkett14 September,2007
Event Reconstruction – tuning for maximum sensitivity
• All backgrounds• NC background• νμ CC background
‣“Primary cuts” = reconstruction,
containment, and number of hits‣ANN is 39.3%
Efficient for events passing primary cuts.
Note that here, sin2213 = 0.1, w/o matter effects
TAUP 2007R. Plunkett14 September,2007Muon Neutrino CC Display
TAUP 2007R. Plunkett14 September,2007Electron Neutrino CC Event
TAUP 2007R. Plunkett14 September,2007
Excellent Sensitivity to e Appearance
3 sensitivity for non-zero 13
NOvA gives order of magnitude improvement (compared to CHOOZ 90%) for most values of CP-.
TAUP 2007R. Plunkett14 September,2007
NovA studies the neutrino mass hierarchy using matter effects
App
eara
nce
Pro
bs.
Typical values for L=810 km, sin2213 = 0.05
anti-
Normal hierarchy
In these regions, and anti- rates are difficult to distinguish.
Inverted hierarchy
anti-
CP phase (0-2)
TAUP 2007R. Plunkett14 September,2007Sensitivity to Mass Hierarchy
95% C.L.Normal
Inverted
Intercept with T2K curve resolves ambiguityTogether, may also have implications for CP-violation
TAUP 2007R. Plunkett14 September,2007
Sensitivity to CP violation using 1.2 MW
NOvA gives clues as to future direction of neutrino program. Will ultra-precise neutrino sources be needed?
TAUP 2007R. Plunkett14 September,2007
Precision Measurement of m2
23,sin2223
6 years at 700 kW 6 years at 1.2 MW
For comparison, current situation (note scale)
TAUP 2007R. Plunkett14 September,2007
95% C.L. Resolution of θ23 Ambiguity
If sin2(2θ23)≠1 then:
θ23>π/4 => e couples more to νμ
θ23<π/4 => e couples more to ντ
NOvA combined with a precise reactor experiment (eg. Daya Bay) can resolve this ambiguity
TAUP 2007R. Plunkett14 September,2007Provisional Project Schedule
Building construction
Accelerator shutdown: Injection lines and ND
excavationNuMI switch to ME configuration
Start of FD operation
TAUP 2007R. Plunkett14 September,2007Summary and Conclusions
• Extensive technical and approval progress for NOvA project– Incorporated accelerator
upgrade to 700 kW– Finalizing structural design– Successful extrusions– DOE CD1 approval
• Nova experiment next step in use of NuMI beamline and its upgrades.– Mixing strength, mass
hierarchy, direction to pursue for CP violation
• Highly complementary to T2K experiment– Combination of results will
define field.• On track for first detector
(IPND) start in 2008.
IPND extrusions at manufacturer
TAUP 2007R. Plunkett14 September,2007
And now, special feelings for Sendai...
Nature is speaking.Sky, earth, beams of neutrinos;
Will we see the way?