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LENS: Measuring the Neutrino Luminosity of the Sun R. S. Raghavan Virginia Tech

LENS: Measuring the Neutrino Luminosity of the Sun R. S. Raghavan Virginia Tech Henderson Capstone DUSEL Workshop Stony Brook University May 5, 2006. LENS-Sol / LENS-Cal Collaboration (Russia-US: 2004-). Russia: INR (Moscow): I. Barabanov, L. Bezrukov, V. Gurentsov,

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LENS: Measuring the Neutrino Luminosity of the Sun R. S. Raghavan Virginia Tech

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  1. LENS: Measuring the Neutrino Luminosity of the Sun R. S. Raghavan Virginia Tech Henderson Capstone DUSEL Workshop Stony Brook University May 5, 2006

  2. LENS-Sol / LENS-Cal Collaboration (Russia-US: 2004-) Russia: INR (Moscow): I. Barabanov, L. Bezrukov, V. Gurentsov, V. Kornoukhov, E. Yanovich; INR (Troitsk):V. Gavrin et al., A. Kopylov et al.; U. S.: BNL: A.Garnov, R. L. Hahn, M. Yeh; U. N. Carolina: A. Champagne; ORNL: J. Blackmon, C. Rasco, A. Galindo-Uribarri; Princeton U. : J. Benziger; Virginia Tech: Z. Chang, C. Grieb, M. Pitt, R.S. Raghavan, R.B. Vogelaar;

  3. “Very Super” Neutrino Beam from the Sun • Best part --Free of Charge • For NEUTRINO PHYSICS: • WELL DEFINED HIGHEST FLUX (pp) • FLAVOR PURE - νe only • LONGEST BASELINE • LARGEST MASS OF HIGH DENSITY • LOWEST ENERGIES (keV to MeV) • LOW ENERGY SPECTRUM - ENERGY DEP. EFFECTS • Best tools for investigating neutrino flavor phenomena in Vacuum and in Matter • For ASTROPHYSICS • Best tool for unprecedented look at how a real Star works • - in the past, present and future

  4. Solar Neutrinos What we know: • Standard Solar Model • Missing e (Cl, Ga, SK, SNO) • Flavor mixing happens (SNO) • Leads naturally to New Era of precision measurements and tests

  5. Solar Luminosity: Neutrino vs. Photon Critical Test if All solar energy is nuclear:  Neutrino luminosity = Photon Luminosity Experimental status after 40 y of solar nu’s– No useful constraint for critical test of Neutrino physics or solar astrophysics!

  6. Solar Luminosity: Neutrino vs. Photon Three main contributions: pp 0.925 7Be 0.075 8B 0.00009 Measuring Neutrino Luminosity  Measuring pp, and other low energy neutrinos • Accent of future test of nu luminosity • on • Individual fluxes of • LOW ENERGY Neutrinos • especially pp neutrinos • Direct spectroscopy • PRECISION Fluxes • No direct pp neutrinos so far • New Experiments needed

  7. LENS-Indium: SCIENCE GOAL Precision Measurement of the Neutrino Luminosity of the Sun • LENS-Sol: • Measure the low energy solar electron - spectrum • (pp, 7Be, pep, CNO) • ± ~3% pp-  flux in 5 years of data • Experimental tool: Tagged CC Neutrino Capture in Indium • LENS-Cal: • Measure precise B(GT) of 115In CC reaction using MCi 51Cr neutrino source at BAKSAN • Tagged -capture to specific level of 115Sn • Note: B(GT) = 0.17 measured via (p,n) reactions

  8. NEW SCIENCE - Discovery Potential of LENS APS Nu Study 2004Low Energy Solar Nu Spectrum: one of 3 Priorities In the first 2 years (no calibration with -source needed): • Test of MSW LMA physics - no specific physics proof yet ! • Pee(pp)=0.6 (vac. osc.) Pee(8B)=0.35 (matter osc.), as predicted? • Non-standard Fundamental Interactions? • Strong deviations from the LMA profile of Pee(E)? • Mass Varying Neutrinos? • (see above) • CPT Invariance of Neutrinos? • so far LMA only from Kamland , is this true • also for ? • RSFP/ Nu magnetic moments • Time Variation of pp and 7Be signals? (No Var. of 8B nus !) • (Chauhan et al JHEP 2005) Low Energy Neutrinos: Only way to answer these questions !

  9. New Science from Relative Fluxes Mass-varying neutrinos MSW-LMA Profile Non-standard interactions Deviations from standard survival probability in various new scenarios

  10. NEW SCIENCE - Discovery Potential of LENS In 5 years (with - source calibration): • pp, 7Be -fluxes at earth ±3%  Measured Neutrino Luminosity ~4% •  Ultimate test of the Sun And the Neutrino •  Astrophysics: L > Lh Is the sun getting hotter? • L < Lh Cooling or a sub-dominant non-nuclear • source of energy in the sun? • Test also neutrino physics  because the Lνderivation needs best • known nu parameters • Precision values of θ12, θ13 (from cos4θ13 dependence of all fluxes) • Sterile Neutrinos? ( especially with CC from LENS and NC from • electron scattering)

  11. LENS-Indium: Foundations CC -capture in 115In to excited isomeric level in 115Sn • Tag: Delayed emission of (e/)+  • Threshold: 114 keV  pp-’s • 115In abundance: ~ 96% • Background Challenge: • Indium-target is radioactive! • (t = 6x1014 y) • 115In β-spectrum overlaps pp-signal • Basic background discriminator: • Time/space coincidence tag • Tag energy: E-tag = Eβmax+116 keV • 7Be, CNO & LENS-Cal signals • not affected by Indium-Bgd!

  12. Expected Result: Low Energy Solar -Spectrum Tag Delayed coincidence Time Spectrum • LENS-Sol Signal • = • SSM(low CNO) + LMA • x • Detection Efficiency e • pp:e = 64% • 7Be:e = 85% • pep:e = 90% • Rate: pp 40 /y /t In • 2000 pp ev. / 5y ±2.5% • Design Goal: S/N ≥ 3 Signal area Bgd S/N = 1 S/N = 3 Coincidence delay time μs Fitted Solar Nu Spectrum (Signal+Bgd) /5 yr/10 t In pp S/N=3 SIMULATION 7Be Indium Bgd CNO pep Access to pp spectral Shapefor the first time 7Be* Signal electron energy (= Eν – Q) (MeV)

  13. In-LENS: Studied Worldwide Since 1976! Dramatic Progress in 2005 Status Fall 2003 Status Fall 2005 • In Liq. Scint. • New Design • Bgd Structure • New Analysis • Strategy Longit. modules + hybrid (InLS + LS) InLS: 5% In, L(1/e)=1.5m,230 pe/MeV Total mass LS: 6000 t In: 30t for 1900 pp ’s /5y PMTs: ~200,000 pp- Detection Efficiency: ~20% S/N~1 (single decay BS only) ~1/ 25 (All In decay modes) Cubic Lattice Non-hybrid(InLS only) InLS: 8% In, L(1/e)>10m,900 pe/MeV Mass InLS : 125t to 190t In: 10t-15t for 1970 pp ’s /5y PMTs: 13,300 (3”) - 6,500 ( 5”) pp- Detection Efficiency: 64-45% S/N ~3 (ALL Indium decay modes) ( MPIK Talk at DPG 03/2004)

  14. Indium Liquid Scintillator BC505 Std 12000 h/MeV 8% InLS (PC:PBD/MSB) 10800 hν / MeV In 8%-photo Light Yield from Compton edges of 137Cs -ray Spectra L(1/e)(InLS 8%) ~ L(PC Neat) ! ZVT39: Abs/10cm ~0.001;  L(1/e)(nominally) >>20 m Norm. Absorbance in 10 cm InLS PC Neat l (nm) Milestones unprecedented in metal LS technology LS technique relevant to many other applications e.g. reactor nu expts for θ13 1. Indium concentration ~8%wt (higher may be viable) 2. Scintillation signal efficiency (working value): 9000h/MeV 3. Transparency at 430 nm: L(1/e) (working value): 10m 4. Chemical and Optical Stabililty: at least 2 years 5. InLS Chemistry - Robust Basic US Patent for metal (In, Sn, Rare Earths…).loading in scint liquids (RSR+EC Bell Labs 2004 )

  15. New Detector Concept - The Scintillation Lattice Chamber Test of transparent double foil mirror in liq. @~2bar Light propagation in GEANT4 Concept 3D Digital Localizabilityof Hit within one cube  ~75mm precision vs. 600 mm (±2σ) by TOF in longitudinal modules  x8 less vertex vol.  x8 less random coinc.  Big effect on Background  Hit localizability independent of event energy

  16. Upper limit ~1700pe/MeV (L=10m) - reach via antireflective coating on films? Adopt 1020 pe/MeV 7.5 cm cells Light loss by Multiple Fresnel Reflection Photoelectron yield versus number of cells: 4x4x4m Cube Absorption length = 10m

  17. Foil Surface Roughness and Impact on the Hit Definition 100 keV event in 4x4x4m cube, 12.5cm cells Perfect optical surfaces : 20 pe (per channel) Rough optical surfaces : 20% chance of non- ideal optics at every reflection 12 pe in vertex + ~8 pe in “halo” • Conclusion - Effect of non-smooth segmentation foils: • No light loss - (All photons in hit and halo counted) • Hit localization accuracy virtually unaffected

  18. Signal Reconstruction • Event localization relies on PMT hit pattern (NOT on signal timing) • Algorithm finds best solution for event pattern to match PMT signal pattern • System is overdetermined, hardly affected by unchannelled light • Timing information + position  shower structure

  19. Indium Radioactivity Background-The Final Frontier β1 (Emax< 2 keV) (b = 1.2x10-6)* SIGNAL BGD 115In E() -114 keV (e1) 115In e/ 116 keV (g2) β0 + n (BS) (Emax = 499 keV) 498 keV  498 keV (g3) 115Sn 115Sn *Cattadori et al: 2003 Multiple 115In decays simulate tag candidate in many ways

  20. Indium Radioactivity Background Background categories 115In –decays in (quasi) prompt RANDOM coincidence produce a tag: Basic tag candidate: Shower near vertex (Nhit ≥ 3) - chance coincident with 115In β in vertex Type A: A1 = β + BS (Etot = 498 keV) (x1) A2 =  (498 keV)(x1) Type B: 2 β-decays (x10-8) Type C: 3 β-decays (x10-16) Type D: 4 β-decays(x10-24) Strong suppression via energy Suppression via tag topology

  21. Indium Background Simulations and Analysis • Data: Main Simulation of Indium Events with GEANT4 • ~ 4x106 In decays in one cell centered in ~3m3 volume (2-3 days PC time) • Analysis trials with choice of pe/MeV and cut parameters (5’ /trial) • Analysis Strategy • Primary selection - tag candidate shower • events with Nhit ≥ 3 • Classify all eligible events (Nhit ≥ 3) • according to Nhit • Optimize cut conditions individually for • each Nhit class • Main Cuts • Total energy: g2+g3 • Tag topology: Distance of lone  from • shower

  22. Background Suppression - Analysis of Tag Candidates “Free” Cuts  Tag analysis must suppress Background by ~2x104  Sufficient to generate ~4x106 n-tuples for the analysis Final Result: Overall Background suppresion > 1011 At the cost of signal loss by a factor ~ 1.6

  23. Typical LENS-Sol Design Figures of Merit – Work in Progress • Scintillator properties: • InLS: 8% In • L(1/e) = 1000cm • LY (InLS) = 9000 h/MeV • Detector Design:

  24. LENS Design Concept (not to scale) 125 ton InLS 10 t Indium 13000 3” PMT’s LS Envelope LS Envelope LS Envelope LS Envelope InLS InLS InLS InLS 5x5x5m 5m 5m Opt. segmentation . Cage Passive Passive Passive Mirror Mirror Mirror PMT PMT PMT Shield Shield Shield 12m 12m

  25. MINILENS--Prototype Final Test detector for LENS LS Envelope • InLS : 128 L • PC Envelope : 200 L • 12.5cm pmt’s : 108 InLS InLS 500 mm 500 mm Opt segmentation cage Passive Passive Mirror Mirror 5 5 ” ” PMT PMT Shield Shield

  26. MINILENS: Global test of LENS R&D • Test detector technology • Large Scale InLS • Design and construction • Test background suppression of In • radiations by 10-11 • Demonstrate In solar signal detection • in the presence of high background • Direct blue print for full scale LENS

  27. “Proxy” pp- events in MINILENS • Proxy pp nu events in MINILENS from cosmogenic 115In(p,n)115Sn isomers • Pretagged via , p tracks • Post tagged via n and • 230 s delay •  Gold plated 100 keV • events (proxy pp), • Tagged by same cascade • as In- events •  Demonstrate In- Signal • detection even in • MINILENS

  28. Summary Major breakthroughs: • ●In LS Technology • ● Detector Design • ● Background Analysis • Basic feasibility of In-LENS-Sol secure ● extraordinary suppression of In background • (all other Bgd sources not critical) • ●Scintillation Chamber – InLS only • ●High detection efficiency  low detector mass • ●Good S/N IN SIGHT: Simple Small LENS (~10 t In /125 t InLS) Next Step Test of all the concepts and the technology developed so far: MINI-LENS - 130 liter InLS scintillation lattice detector

  29. Large (50-100kT) Liquid Scintillation Detector For keV-GeV Multidisciplinary Science HYPER SCINTILLATION DETECTOR HSD

  30. HSD • 100 KT LIQUID SCINTILLATION DEVICE? • Next generation device beyond CTF, Borexino, Kamland, LENS… • The technology now has a large worldwide group of experts with • experience/expertise in constructing and operating massive LS • detectors (upto 1 kT so far), for precision low energy (>100 keV ) • astro-particle physics • Essential questions for a large scale project like this: • What science can be achieved that may be unique? • Can one achieve multidisciplinary functionality? • Are the possible science questions of first rank impact? • Can it be competitive with other large scale detector • technologies in science payoff, cost. technical readiness …?

  31. Working Group (Theory and Experiment): • F.Feilitzsch, L. Oberauer (TU Munich0 • R. Svoboda (LSU) • Y. Kamyshkov, P. Spanier (U. Tennessee) • J. Learned, S. Pakvasa (U. Hawaii) • K. Scholberg (Duke U.) • M. Pitt, B.Vogelaar, T. Takeuchi, C. Grieb, • Lay Nam Chang, R. S. R (VT) • Bring together earlier work: • Munich Group -LENA (aimed at a European site) • R. Svoboda et al • Y. Kamishkov et al • RSR

  32. LS Technology (Targets in LS: 12C, p) • Pluses: +Signal x50 that of Cerenkov • +Low Energy (>100 keV) Spectroscopy • (in CTF (5T, 20% PMT coverage) 14C spectrum >30 keV) • +Heavy Particle Detection well below C-threshold • +Tagging of rare events by time-space correlated cascades • +Ultrapurity-ultralow bgds even < 5 MeV (radio “Wall”) • +Technology of massive LS well established • Minus: -Isotropic signal—no directionality • Unique Tool for Anti-Neutrino Physics • ==Nuebar tagging by delayed neutron capture by protons • Very low fluxes (~1/cm2/s @5 MeV) conceivable with care and effort: • Good depth to avoid b-n cosmogenics (e.g. 9Li—prefer no heavy • element for n-capture) • Efficient muon veto of n, std 5m water shield to cut n, PMT, rock g • Ultrapurity to cut internal g < 5 MeV • Locate far from high power reactors

  33. Main Topics in Focus • Particle Physics • Proton Decay • Long baseline Neutrino Physics—especially with nuebars • Geophysical Structure and Evolution of Earth • Global measurement of the antineutrinos from U, Th in • the interior of the earth • ( Fission Reactor at the center of the earth ??? ) • Supernova Astrophysics and Cosmology • Supernovae—Real time detection • Relic Supernova Spectrum • Pre-supernova Pair emission of C,O, Ne or Si burning

  34. Terrestrial Terrestrial Radiogenic Radiogenic Energy Sources Location Energy Sources Location 1) Radioactivity of U and 1) Radioactivity of U and Th Th (and others) (and others) Mostly Mostly Crustal Crustal Layer Layer 2) Fission Reactor ?? In 2) Fission Reactor ?? In ner Core ner Core 3) Man 3) Man - - made Power Reactors Surface made Power Reactors Surface ALL ABOVE SOURCES EMIT ANTINEUTRINOS ALL ABOVE SOURCES EMIT ANTINEUTRINOS • • ANTINEUTRINO SPECTROSCOPY CAN PROBE THE EARTH ANTINEUTRINO SPECTROSCOPY CAN PROBE THE EARTH • • Just as neutrino spectroscopy has probed the Sun Just as neutrino spectroscopy has probed the Sun • • TECHNOLGY MATURE AND AVAILABLE TECHNOLGY MATURE AND AVAILABLE • • PARASITIC MEASUREMENT IN DETECTORS FOR OTHER PHYSICS PARASITIC MEASUREMENT IN DETECTORS FOR OTHER PHYSICS • • TIMELY TO CONSIDER FOR NUSL TIMELY TO CONSIDER FOR DUSEL Long Literature: Problem: G. Elders (1966) Long Literature: Problem: G. Elders (1966) G. Marx (1969) G. Marx (1969) Detection methods; Krauss et al Na Detection methods; Krauss et al Na ture 310 191 1984 (and ref therein)...many others ture 310 191 1984 (and ref therein)...many others Raghavan et al PRL 80 635 1998 Spectroscopy & Specific Model Tests: Rotschild et al, Geophys. Res. Lett. 25,1083 1998

  35. Homestake 4850’ Henderson MC South Pole(Amanda/ice3)

  36. Henderson Homestake Power reactors Possible Nuclear Reactor Background Sources for HMSTK & Hndrsn

  37. (RSR et al PRL 80 (635) 1998) Aug 2005—New Glimpse of U/Th Bump in Kamland! Birth of Neutrino Geophysics Situation like 1964 in solar Neutrinos

  38. Reactor bgd/Kt/yr Kamioka: 775 Homestake: 55 WIPP: 61 San Jacinto: 700 Kimballton: ~100 (RSR hep-ex/0208038a0

  39. Super Nova Relic (Anti) Neutrino Sensitivity Super Nova Relic (Anti) Neutrino Sensitivity ( ( Strigari Strigari et al) et al) • Low Energy Sensitivity • is KEY for: • High Rates • Access to HIGH red • Shift part 1kT 1kT 1kT LENS LENS LENS - - - - - - - Sol 3.75 Sol 3.75 Sol 3.75 kT kT kT (Lower Reactor (Lower Reactor (Lower Reactor Bgd Bgd Bgd ) ) )

  40. C Pre SN ν emission from 20Msun Star via pair Annihilation O, Ne) Solar pp Si Detect ν̃e with tag. 20 Msun Star at 1kpc Odrziwolek et al Astro-ph/0405006

  41. Limitations from Limitations from Cerenkov Cerenkov Threshold Threshold • • No K+ from 2 No K+ from 2 - - body nucleon decay can be body nucleon decay can be seen directly seen directly • • many nuclear de many nuclear de - - excitation modes not excitation modes not visible directly visible directly • • “stealth” “stealth” muons muons from atmospheric neutrinos from atmospheric neutrinos serious background for proton decay, relic SN serious background for proton decay, relic SN search search

  42. HSD enables search for Mode-free Nucleon Decay • Disappearance of n in 12C leads to 20 MeV excitation of 11C followed by delayed coincidences at few MeV energy • This pioneering technique opens the door to a very different way of looking for nucleon decay –best facilitated in LS technique • Kamyshkov and Kolbe (2002)

  43. Conclusions: • HSD will be a Major Science Opportunity • Top notch multi-disciplinary science • justifying cost (~300M?) • Geophysics • SN physics and cosmology • Proton/nucleon decay • #1 not possible in any other detector—Uniqueness--Discovery • #2 best served by low energy sensitivity-- • higher event yields and access to • high red shift cosmology— • best chance for definitive landmark result • #3 better opportunities in HSD than Cerenkov • and at least as good handles as in LAr

  44. Conclusions Henderson DUSEL offers attractive opportunities For Scintillation based detectors LENS and HSD That Between them cover a large swath of top class Science

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