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Status of the NOvA Experiment

Status of the NOvA Experiment. Robert Plunkett Fermi National Accelerator Laboratory Batavia, IL, USA. TAUP 2007 Topics on Underground and Astroparticle Physics 14 September 2007. The NOvA Collaboration. 25 Institutions, 129 Physicists and Engineers

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Status of the NOvA Experiment

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  1. Status of the NOvA Experiment Robert Plunkett Fermi National Accelerator Laboratory Batavia, IL, USA TAUP 2007 Topics on Underground and Astroparticle Physics 14 September 2007

  2. The NOvA Collaboration 25 Institutions, 129 Physicists and Engineers Argonne, 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

  3. Ash River Site for NOvA Located 30 km south of Canada Improved road access planned 810 km baseline 14.6 mrad off-axis

  4. p beam Pion beam Decay Pipe 250 m NuMI Tunnels and Facility NuMI Pretarget Area NuMI Components in Main Injector

  5. ExistingNuMI Neutrino Beam Horn and Stripline 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)

  6. Upgrades 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

  7. Expected evolution of proton intensity Possible upgrade path Requires use of recycler storage ring after Tevatron shutdown Achieved! Expected after current shutdown

  8. Graphical Representation of Off-Axis Beam Length of this vector very insensitve to pion g At ~ p/2 DPT@ 0 as vary q* Flux peaks in desired region

  9. Off-axis provides improved background levels NC at low energy because no high energy tail Backgrounds show a different energy spectrum and can be removed during analysis Beam ne are spread out over a wide range - remove by windowing

  10. Three NOvA Detectors • 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

  11. NOvA Building a considerable structure 107 m Block assembly area 19 m Pulsed beam allows surface construction. Overburden of 1.2m concrete, and 30 cm Barite reduces C.R. backgrounds (especially g) to low levels

  12. 1-cm expan- sion gap 31-plane block 31-plane block Construction in Subsections for Structural Stability Each block has ~6000 channels Filling proceeds as blocks constructed Detailed mechanical analysis for stability against bulge, creep. Block pivoter raises 127 Ton blocks

  13. Extruded PVC tubes filled with liquid scintillator Prototype with full-length fiber Readout cosmic muons ~ 16 m

  14. 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 length 5.5% 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

  15. Extrusion Structure and Initial Production 16 Cell extrusions – ready for further assembly 15.8 m in length is long.

  16. NOvA HPD Detector Electronics APD on prototype carrier board QE ~85%, gain ~100 QE well-matched to fiber spectrum Cooled by thermoelectric cooler to -15 C Untriggered continuous digitization Emission Spectra and Q.E. Water cooling for TEC’s

  17. target volume veto muon ranger showercontainment MINOS underground area allows a Near Detector 218 tons total / 20 tons fiducial At low q13, reducing uncertainty on background at far detector can increase sensitivity by even more than additional exposure

  18. Electron Identification for NOvA >20 variables in Neural Net Examples shown – other variables study charge-range distributions Overall efficiency ~30% (optimizable) NC signal nmCC bkg. signal nm CC nmCC NC beamne signal Neural Net Output

  19. All backgrounds • NC background • νμ CC background Event Reconstruction – tuning for maximum sensitivity • “Primary cuts” = reconstruction, containment, and number of hits • ANN is 39.3% Efficient for events passing primary cuts. Note that here, sin22q13 = 0.1, w/o matter effects

  20. Muon Neutrino CC Display

  21. Electron Neutrino CC Event

  22. Excellent Sensitivity to ne Appearance 3s sensitivity for non-zero q13 NOvA gives order of magnitude improvement (compared to CHOOZ 90%) for most values of CP-d.

  23. Inverted hierarchy Normal hierarchy n anti-n anti-n n NovA studies the neutrino mass hierarchy using matter effects Appearance Probs. d CP phase (0-2p) Typical values for L=810 km, sin22q13 = 0.05 In these regions, n and anti-n rates are difficult to distinguish.

  24. Sensitivity to Mass Hierarchy Intercept with T2K n curve resolves ambiguity Together, may also have implications for CP-violation Normal 95% C.L. Inverted

  25. 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?

  26. Precision Measurement of Dm223,sin22q23 6 years at 700 kW 6 years at 1.2 MW For comparison, current situation (note scale)

  27. 95% C.L. Resolution of θ23 Ambiguity If sin2(2θ23)≠1 then: θ23>π/4 => ne couples more to νμ θ23<π/4 => ne couples more to ντ NOvA combined with a precise reactor experiment (eg. Daya Bay) can resolve this ambiguity

  28. Start of FD operation Accelerator shutdown: Injection lines and ND excavation NuMI switch to ME configuration Building construction Provisional Project Schedule

  29. Summary 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

  30. And now, special feelings for Sendai... Nature is speaking. Sky, earth, beams of neutrinos; Will we see the way?

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