TAUP 2007 R. Plunkett 14 September,2007 Status of the NOvA Experiment Robert Plunkett Fermi National...

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


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


Expected evolution of proton intensity

Achieved!

Expected after current shutdown

Requires use of recycler storage ring after Tevatron shutdown

Possible upgrade

path


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


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


•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


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


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.


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


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


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


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


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


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-.


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


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?


Precision Measurement of m2

23,sin2223

6 years at 700 kW 6 years at 1.2 MW

For comparison, current situation (note scale)


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


And now, special feelings for Sendai...

Nature is speaking.Sky, earth, beams of neutrinos;

Will we see the way?

TAUP 2007 R. Plunkett 14 September,2007 Status of the NOvA Experiment Robert Plunkett Fermi National...

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