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The MINOS Experiment

The MINOS Experiment. Our Physics Goals The NuMI beamline The MINOS Detectors Some first data! Protons! Physics Measurements and Sensitivity Summary. Douglas Michael California Institute of Technology Fermilab User’s Meeting June 3, 2003. (N m / N e ) data. R=.

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The MINOS Experiment

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  1. The MINOS Experiment • Our Physics Goals • The NuMI beamline • The MINOS Detectors • Some first data! • Protons! • Physics Measurements and Sensitivity • Summary Douglas Michael California Institute of Technology Fermilab User’s Meeting June 3, 2003

  2. (Nm/Ne)data R= No Oscillation Best Fit nm-nt oscillation: sin2 2q = 1.0, Dm2 = 0.0025 eV2 (Nm/Ne)MC Super-Kamiokande Data = 0.64 for E<1.3 GeV = 0.66 for E>1.3 GeV

  3. Soudan 2 SK Allowed Oscillation Parameters nm - nt • Super-K Best Fit: • Dm2 = 0.0025 eV2 • sin2 2q = 1.0 • MACRO Best Fit: • Dm2 = 0.0025 eV2 • sin2 2q = 1.0 • since 1998! • Soudan 2 Best Fit: • Dm2 = 0.01 eV2 • sin2 2q = 1.0 MACRO upmu MACRO L/E MACRO Low Energy

  4. Neutrino Oscillations Are Beyond Standard Model We Need Precision Measurements!

  5. MINOS Physics Goals • Demonstrate Oscillation Behavior • Precise measurement of CC energy distribution between near and far detector (2-4% sys. uncertainty in En per 2 GeV bin). • “Standard” or non-standard oscillations? • Can we see clear “oscillatory” behavior from the first osc. max? Rise at low energy? • Are there features in the energy spectrum not well described by a standard oscillation? • Precise Measurement of Oscillation Parameters • How close to 1.0 is sin2 2q23? Are we looking at a new fundamental symmetry? • Precise Determination of Flavor Participation • Number of CC nmevents far/near ~2%: Probability for nm - nx oscillation. • Number of CC ne events far/near: Sensitive to nm - ne oscillation down to about 2%. Discovery/first measurement of Ue3? For the future… CP violation? • Number of NC events far/near: probability for nm - nsterile oscillation down to about 10%. • nm’s which disappear but don’t appear as ne or disappear to nsterilemust be nt! • Direct Measurement of Atmospheric n vs n. CPT Violation?

  6. The MINOS Collaboration Argonne – Athens – Brookhaven – Caltech – Cambridge – College de France Fermilab – Harvard – IIT – Indiana – ITEP-Moscow – Lebedev – Livermore – University College London – Macalester – Minnesota – Minnesota-Duluth – Oxford – Pittsburgh – Protvino - Rutherford – South Carolina – Stanford – Sussex – Texas A&M – Texas-Austin – Tufts – UNICAMP/USP-Brazil – Western-Washington - Wisconson

  7. Near Detector: 980 tons Det. 2 Det. 1 735 km The MINOS Experiment • Precision measurements of: • Energy distribution of oscillations • Measurement of oscillation parameters • Participation of neutrino flavors • Direct measurement of n vs n oscillation • Magnetized far detector: atm. n’s. • Likely eventual measurement with beam Far Detector: 5400 tons

  8. Design Parameters for NuMI • 120 GeV protons • 1.9 second cycle time • 4x1013 protons/pulse • 0.4 MW! • Single turn extraction (10ms) • 4x1020 protons/year • Initial intensity will be less… • 2.5x1020 protons/year? • Possible to go beyond 4x1020/year with investment in the accelerator complex? Near detector

  9. Status of NuMI Beamline Construction • The excavation of the NuMI beamline halls and tunnels is complete. • The decay pipe is installed along with the concrete shielding. • The outfitting of the tunnels and halls is well advanced. Done by November. • The surface buildings are being built. • First protons on target expected in December 2004.

  10. Out of the Main Injector Into the Ground 3D drawing of the NuMI extraction line coming out of the MI below the Recycler. The main vertical bend to send the protons down into the NuMI tunnel .

  11. The NuMI Decay Tunnel

  12. The Decay Pipe Pipe is embedded in concrete to protect groundwater.

  13. The NuMI Target Hall

  14. Beam Components Waiting for Installation Target from Protvino Horn 2 Part of NuMI shielding

  15. Fabrication and Testing of Horns Horn 2 inner conductors. Prototype horn 1 in test stand Assembly of Horn 2.

  16. MINOS Hall in May Near Detector support structure

  17. NuMI Surface Buildings Target Service Building (MI-65) MINOS Service Building (The thing on Pine Street)

  18. Getting the Main Injector Ready • MI Multi-batch Studies • Different than for Run II • Resumed May 21 • Team included members of the MI Dept, MINOS collaborators, BD operators • Within 30 minutes achieved new MI intensity record • Detailed study/work program being worked out • Lots more work yet to do! 2.5 x 1013 protons!

  19. nm CC Events/kt/year Low Medium High 470 1270 2740 nm CC Events/MINOS/2 year Low Medium High 5080 13800 29600 4x1020 protons on target/year 4x1013 protons/2.0 seconds The NuMI Neutrino Energy Spectra By moving the horns and target, different energy spectra are available using the NuMI beamline. The energy can be tuned depending on the specific oscillation parameters expected/observed.

  20. The MINOS Far Detector • 8m octagonal steel & scintillator tracking calorimeter • Sampling every 2.54 cm • 4cm wide strips of scintillator • 2 sections, 15m each • 5.4 kton total mass • 55%/E for hadrons • 23%/E for electrons • Magnetized Iron (B~1.5T) • 484 planes of scintillator • 26,000 m2 One Supermodule of the Far Detector… Two Supermodules total.

  21. Detector Technology • Scintillator strips are extruded polystyrene (Itasca Plastic) • PPO (1%) and POPOP (0.03%) fluors • Co-extruded TiO2 reflective coating • Fiber groove • Kuraray 1.2mm WLS Fibers • (Y-11 175ppm) • PMTs: • Far Detector: Hamamatsu R6000-M16 multi-anode PMTs (16 channels), 8 fibers/pixel. • Near Detector: “M64”, one fiber per pixel. • Viking “VA”-based front-end electronics.

  22. Status of MINOS Construction • The far detector is >99% built and operating. • The magnetic field is on in the first half. • The full detector will be complete in • June 2003. • A cosmic-ray veto shield is installed on • 3/4 of the detector. • Cosmic Ray data are being collected • for calibration and commissioning. • Atmospheric Neutrino data are being collected Detector on June 2, 483/484 planes installed. • Essentially all being read out. • Working according to spec’s • 9 photoelectrons/plane/muon • 2.6 ns/plane time resolution

  23. More MINOS Far Detector Photos The plane assembly area and mural, looking towards the installed detector. A veto side-wall built from scintillator modules

  24. Show the Movie

  25. The Near Detector • 3.8 x 4.8m “octagonal” steel & scintillator tracking calorimeter • Same basic construction, sampling and response as the far detector. • No multiplexing in the main part of the detector due to small size and high rates. • Hamamatsu M64 PMT • Faster Electronics (QIE) • 282 planes of steel • 153 planes of scintillator

  26. Near Detector Assembly • Assembly of near detector planes is complete on • the surface at Fermilab. • Assembled planes will transferred (one at a time) • underground once the hall is ready. This will allow the ND • to be commissioned in time for beam turn-on.

  27. The MINOS Calibration Detector • A mini-version of the MINOS near and far detectors • 1m x 1m x 3.7 m • 60 planes x 24 strips/plane • Readout technologies of both the near and far detectors • Being exposed to electron, pion, proton and muon beams from 0.5-10 GeV/c momentum at the CERN PS. • First data in 2001 up to 3.5 GeV using far detector readout. • Data in 2002 up to 10 GeV and to compare near and far electronics. • Additional running in 2003 with full near readout system. • Physics Goals: • EM and Hadron energy response • EM and Hadron event topology • Near/Far readout comparison Last Dipole T11 Beam Line Electronics and PMTs 1m 24 strips x 60 (3.7 m) Scintillator 1m Steel 5.9 cm

  28. Example Caldet events: 2 GeV Electron Pion Muon Proton Strip Plane

  29. Particle Response (preliminary) MC expectation

  30. Upward-Going Muons _ _ _ m,m MINOS All events:stopping & through going _ n,n Monte-Carlo Expectation with no oscillations Earth

  31. y x z Direction Determination • Use Y direction timing and direction cosines at vertex to identify upward-going muons • Tight 1/b (=c/v) distribution indicates good timing • Negative 1/b values indicate upward-going muons • Peak at 1/b = -1 clearly seen s = 0.056

  32. Example Upgoing Event m+ with p = 5.4 GeV/c Time vs z Time vs y y x y vs x z y vs x Strip vs Plane

  33. Preliminary Upward-Going Muon Flux • Horizon at cos q = 0.0 • Nadir at cos q = -1.0 • cos q bins of 0.1 • There are 12 upward going events in the data sample cos(zenith)

  34. Charge and Momentum of Upgoing Muons One Sign The Other Sign • All muons are assigned a charge based on the most likely hypothesis. • Above 100 GeV, the charges and the momenta are not very reliably • determined at this time. • Below 70 GeV, charge and momenta are generally well determined.

  35. A medium energy contained vertex event nm interaction

  36. Atmospheric Neutrino Measurements • MINOS is the first large underground detector which has a magnetic field. • Measure charge/momentum of muons from ~0.5-100 GeV/c momentum. • Events with the neutrino interaction in the detector but where the muon exits still have complete Enmeasurement: L/E measurements. • Event direction reconstructed using timing and topology. • Able to identify CC nmand nm events from NC and CC ne events over a very broad energy range as long as pm> ~1 GeV/c. • We can directly compare whether atmospheric nmand nm oscillate in the same way. Probability of c2 for nominal neutrino oscillation Parameters compared to different values of dm**2 For antineutrinos. Number of events in 24 kT years Neutrino Antineutrino Reconstructed contained vertex with muon 620 400 Reconstructed upgoing muon 280 120

  37. MINOS Running Plan • Draft Fermilab Long-Range Plan: • NuMI beam commissioning starting in Dec. 2004. • 4 years of physics running for MINOS starting in April 2005. • Goal for protons on target in first year = 2.5 x 1020 • Plans are being developed for increased proton intensity. • New MINOS Running Request (May 2003) • MINOS has submitted a request to Fermilab for 5 years of running with a total of 25 x 1020 protons on target in that time. • MINOS has provided updated physics sensitivity curves based on 7.4, 16 and 25 x1020 total protons on target. (Original MINOS physics sensitivity was based on 7.4 x 1020 pot.) • There are several options for providing this number of protons. • MINOS collaborators want to help with proton intensity!!! Precision Oscillation Measurements Require a Lot of Protons!

  38. Topology of Neutrino Events nmCC n n • Two views of a nmCC event with the neutrino interaction at the left side moving to the right. Each histogram bin is one scintillator strip. The height of each bin is the number of observed photo-electrons (energy deposition). • Identified by a relatively long/simple track in an event. At very low energies, there can be some background from NC p-. • The near detector is used to understand event identification.

  39. Topology of Neutrino Events neCC n n “Quasi-elastic” event with a 4 GeV electron • Two views of a ne CC event with the neutrino interaction at the left side moving to the right. Each histogram bin is one scintillator strip. The height of each bin is the number of observed photo-electrons (energy deposition). • Identified by lack of a long track and with a relatively concentrated EM shower in the core. Main background comes from NC p0 events.

  40. Topology of Neutrino Events nmNC n n • Two views of a nm NC event with the neutrino interaction at the left side moving to the right. Each histogram bin is one scintillator strip. The height of each bin is the number of observed photo-electrons (energy deposition). • Identified by lack of a long track and and lack of a strong EM shower in the core. Some high y CC events are background.

  41. Measurement of Oscillations in MINOS For Dm2 = 0.0025 eV2, sin2 2q = 1.0 Oscillated/unoscillated ratio of number of nmCC events in the far detector vs Eobserved MINOS 90% and 99% CL allowed oscillation parameter space.

  42. Measurement of Oscillations in MINOS For Dm2 = 0.0016 eV2, sin2 2q = 1.0 Oscillated/unoscillated ratio of number of nmCC events in the far detector vs Eobserved MINOS 90% and 99% CL allowed oscillation parameter space.

  43. Appearance of Electrons For Dm2 = 0.0025 eV2 For Dm2 = 0.0025 eV2, sin2 2q13= 0.067 3 s discovery potential for three different levels of protons on target and versus systematic uncertainty on the background. Observed number of events identified as coming from ne CC interactions with and without oscillations. 25x1020 protons on target.

  44. Appearance of Electrons (5 years, 3kt) Dm2 = 0.0025 eV2 90% CL Exclusion Limits MINOS 3s Discovery Limits • MINOS sensitivities based on varying numbers of protons on target

  45. NuMI Off-Axis • Build a new ~50 kt fine-grained, low Z detector in northern Minnesota or Canada • Beam energy defined by the detector position (~20 mR off-axis gives an optimum beam. • Narrow energy range (minimizes NC-induced background) • Simultaneous operation (with MINOS and/or other detectors) • Improve on MINOS oscillation measurements due to lower energy, narrow-band beam with much higher statistics due to more protons on target and much bigger detector. • Discover or better measure Ue3 and other oscillation parameters • Matter effects can amplify oscillation probability and be used to determine mass heirarchy • Search for CP violation

  46. Conclusions • The MINOS Detectors together with the NuMI beam will permit a next step in precision measurements of “atmospheric” neutrino oscillations: • Precise energy distribution… Showing the oscillation signature (?) • Precise measurement of Dm2 • Precise determination of participation of different neutrino flavors • Extend sensitivity for small nm - ne mixing • Measurement of anti-neutrino mixing for atmospheric neutrinos • Construction of the MINOS far detector is ~99% complete and cosmic ray data is being accumulated with installed planes. • Data acquisition for cosmic rays and atmospheric neutrinos underway! • Construction of the NuMI beamline is nearing completion. The tunnel excavation is complete. The outfitting and final civil construction is on schedule. The installation of beam components and near detector is ready to go. • First protons on target scheduled for December 2004. • Running plans, including increased protons on target are being developed. • New proposals for use of the NuMI Beamline are developing.

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