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Neutrino detectors ： Present and Future

Neutrino detectors ： Present and Future. Yifang Wang Institute of high energy physics. Neutrino industry. Neutrino physics ： problems and methods. Oscillation /sterile neutrinos. Magnetic moments. Astro -objects . Atmos-pheric. E arth. Nuclear chemistry.

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Neutrino detectors ： Present and Future

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  1. Neutrino detectors：PresentandFuture Yifang Wang Institute of high energy physics

  2. Neutrino industry

  3. Neutrino physics：problems and methods Oscillation /sterile neutrinos Magnetic moments Astro-objects Atmos-pheric Earth Nuclear chemistry Semiconductor/crystals/gaseous/scintillator Radioactive sources Liquid scintillator Mass Water Cerenkov Accelerator Cosmology Astronomy Geology Solar Reactor Dirac/ Majorana Emulsion Samplingdetector Relic-neutrino Liquid Argon

  4. Selectedtopics • Personnelflavors • Mainly on neutrino oscillations • Present experimental techniques with future prospects • Future trends I apologize for incompleteness, bias and mis-handling

  5. Selected Neutrino Experiments • Basic properties of neutrinos • Magnetic moments: Texono, GEMMA, … • Absolute mass: Katrin,Mare, Project 8, … • Neutrino oscillations & sterile neutrinos • Atmospheric neutrinos(q23): SuperK,INO … • Solar neutrinos(q12):SuperK, SNO, Borexino, … • Reactor neutrinos(q12,q13):KamLAND, DayaBay,Double CHOOZ, Reno,…  mass hierarchy • Accelerator neutrinos(q23,q13): MINOS,OPERA,MiniBooNe, T2K, NOVA,…  mass hierarchy, d, … • Neutrino astronomy& applications • Supernova  in combination with solar/atmospheric/reactor neutrinos • Geo-neutrinos  in combination with solar/reactor neutrinos • High energy neutrinos(not covered in this talk) • …

  6. Neutrino magnetic moments Bohr magnetonB= eh / 2 me • SM: • mn=0 mn(ne)=0 • mn0mn(ne) ~ 10-19 mB • Non-SM： • mn(ne) ~ 10-10-14mB • Astrophysics limit(model dependent) • He star, White dwarf, SN 1987 A, Solar(SuperK, KamLAND, Borexino), … • Directsearches: • 1/T excess in n-e scattering • TEXONO • 1kg ULB-HPGe • Background level: • ~ 1/(day kg KeV) • Threshold: • ~ 10 KeV • Limit: • mn(ne) < 1.3  10-10mB(90% CL)

  7. GEMMA • 1.5 kg HPGeinstalled within NaI active shielding. • Multi-layer passive shielding : electrolytic copper, borated polyethylene and lead • More HpGe, better shielding  Another fact of 10 ? [Phys. of At. Nucl.,67(2004)1948]

  8. Ultra-pure Ge detectors • Common technology for bbdecays, dark matter… • Future advances: • Mass: ~100 kg  1000 kg ? • Threshold: ~10 keV  1 keV ? • Cost: ~ kg/300K $  ~kg/30K $ ? • Efforts in China(Shenzhen U. & Tsinghua U.) to: • Reach the impurity to10-13 • Reduce the cost to < ~kg/30K $ ? Current status: impurity ~ 10-11/cm3 Resolution: 1.76KeV @ 1.33MeV Working on stability & repeatability

  9. Absolute Neutrino mass：bdecays • Requirement: • Source: • Low endpoint • High event rate • appropriate lifetime • Enough source material (thickness affect b spectrum) • Detector: • High resolution • Low background • Experiments: • Sourcedetector: Katrin, Project 8 • Source=detector: Mare

  10. Katrin: b spectrometer T1/2= 12.3 y Magnetic Adiabatic Collimation + Electrostatic Filter A large spectrometer： Sensitivity increase with area Low statistics for relevant events Resolution: ~ 1 eV Sensitivity @ 90%CL: m(n) < 0.2 eV Last such exp. ?

  11. Project 8: Radio Frequency • Electrons moving in a uniform magnetic field emit cyclotron radiation: • Advantages: • Non-destructive measurement of Frequency  energy • Resolution improves over time Dw 1/T  1 eV • Target mass scales with volume • Promising for m(n) < 0.1 eV • Challenges: • Unknownsystematics R&D: Detect the RF signal Understand the resolution Measure the energy spectrum of 83m Kr

  12. Mare： Bolometer Similar Techniquesused also in bb decay and dark matter searches • Bolometer: DT = E/C • Phonons: C ~ T3 (Debye law) at T<< 1K • Event time: DT = E/C e-t/(C/G) • Resolution：sE= (kBT2C)1/2

  13. phase I: DE = 15 eV, mn< 2 eV phase II: DE = 5 eV, mn< 0.2 eV Mare: Phase I • Sensitivity increase with volume: • Arrays of mg-sensors • Up to kg for sub-eVm(n) • R&D on sensor-absorber couplings, pixel design, readout, systematics assessment, etc. • Need: • Higher mass • Lower backgrounds • Better energy resolution Phase II

  14. Neutrino oscillation experiments Technologies Experiments Atmospheric neutrino exp. SuperK，HyperK/UNO，INO，TITAND,… Solar neutrino exp. GALLEX/SAGE, SNO, Borexino, XMASS, … Accelerator neutrino exp. Minos, OPERA, MiniBooNE, T2K, Nova, … Reactor neutrino exp. KamLAND, Daya Bay, Reno, Double Chooz,… • Water Cerenkov detector • Liquid Ar TPC • Liquid Scintillator detector • Sampling detectors for neutrino beams • …

  15. Water Cerenkov detectors • Successful for atmospheric neutrinos, proton decays, supernova, … • Current benchmark set by SuperK: • Mass: 50 kt • PMT coverage: ~40% • Threshold: ~4 MeV • Light yield: 6 PE/MeV • Future ~Mt detector for • Very long baseline neutrino exp. • Proton decays/supernova

  16. Future: LBNE water option • Module spec.: • Total water mass: 138 kt • Fiducial mass: 100 kt • 50000 10” PMT • PMT Coverage: 20% • Light yield: 3 PE/MeV • Threshold: 6MeV • Performance for single rings • Energy resolution: 4.5%/E • vertex resolution: 30cm • Good e/m separation • Multi-rings • Pattern recognition • Event reconstruction 2 100 kt Modules

  17. Technical issues • PMT: under pressure(60m ~ 0.7 Mpa) ? • Water circulation system: • Requirement: Attenuation length > 80 m • Volume: 100 days to fill, > 20 days to circulate 1 volume • Civil • A cavern of 55m diameter, 70m high • Not trivial but also not impossible

  18. Physics reach Performance Similar for 30kt liquid Ar TPC

  19. Even larger water detectors for LBNE, proton decays and supernova 500kton Deep-TITAND (10 Mt) TITAND-I 85m 85m105m4 =3Mt （2.2MtFV) TITAND-II 4 modules  8.8 Mt (400  SK)

  20. GADZOOKS & EGADS ne + p  e+ + n n + p  d + g (2.2 MeV) n + Gd  Gd* + g (8 MeV) • Gd in water: • GdCl3 highly soluble in water • Improve low energy detection capabilities • flavor sensitive • Good for LBNE, supernova, reactor and geo-neutrinos, … • A 200 ton-scale R&D project, EGADS – is under construction at Kamioka t  28 ms(0.1% Gd)

  21. Exotic ideasfor LBNE • Water Cerenkov Calorimeter: • Segmented modules 1  1 10 m3 • two PMTs at each end • Pattern recognition similar to crystal calorimeter Y.F. Wang , NIM. A503(2003)141 M.J. Chen et al., NIM. A562 (2006)214

  22. Liquid Ar TPC: another detector candidate for LBNE • Idea first proposed in 1985 • Dense target • ample Ionization & scintillation: good energy resolution & Low threshold • Excellent tracking and PID capabilities • Digital bubble chamber: • Excellent for discoveries, say ne appearance m decay at rest m.i.p. ionization ~ 6000 e-/mm Time Scintillation light yield 5000 γ/mm @ 128 nm Edrift ~ 500 V/cm Drift direction

  23. ICARUS • Successful After 20 years R&D • Excellent performance • Tracking: sx,y ~ 1mm, sz ~ 0.4mm • dE/dx: 2.1 MeV/cm • PID by dE/dxvs range • Total energy by charge integration • Lessons learned: Impurities (O2, H2O, CO2) should be < 0.1 ppb O2 equivalent 3 ms lifetime (4.5m drift @ Edrift= 500 V/cm) • Two recirculation/purification scheme: Gas & liquid phase Low energy electrons: σ(E)/E = 11% / √E(MeV)+2% Electromagnetic showers: σ(E)/E = 3% / √E(GeV) Hadron shower (pure LAr): σ(E)/E ≈ 30% / √E(GeV)

  24. Successful R&D in Europe, Japan & US Collection view ArgoNeut event in NuMI CNGS nmCC events in ICARUS T600 Drift time coordinate (1.4 m) Wire coordinate (8 m) 250L@KEK

  25. R&D towards LBNE & MicroBooNE • R&D efforts and technical challenges • Long-drift operations(LAr purity) • Membrane cryostat for multi-kiloton TPC • Readout wires or Large electron Multipliers • Cold electronics • MicroBooNE: Combine R&D with physics  A ~100t LAr TPC at Fermilab on-axis Booster beam and off-axis NuMI beam for • MiniBooNE low energy excess • Low energy cross sections

  26. Future: LBNE LAr option • 220kt cryostat • Maximum drift length: 2.5 m  (1.4 ms) • 645000 readout wires (128:1 MUX) • 3mm Wire pitch

  27. Charge readout plane (LEM plane) GAr E ≈ 3 kV/cm LAr Electronic racks Extraction grid E-field E≈ 1 kV/cm Field shaping electrodes Cathode (- HV) UV & Cerenkov light readout PMTs Liquid Argon: other proposals • In Japan: 100kt for JPARK  Okinoshima • In Europe: Modular and Glacier • Modular: • 20 kton proposal at LNGS based on larger 8x8 m2 ICARUS modules • Glacier: • 50-100 kton, Readout: Large GEMs (LEM)

  28. LBNE: LAr or Water ？ Water LAr Pros Beautiful image of events Good energy resolution Good PID and pattern recognition High efficiency Requiring smaller cavern and shallow depth Cons Technology for such a volume ? Huge No. of channels Cost ? • Pros • Proven technology • Cost under control • Good energy resolution (slight worse) • Good PID & pattern recognition, particularly at low energies • Cons • Lower efficiency • Larger cavern and deep underground

  29. Liquid scintillator detectors • Successful for reactor and geo-neutrinos • Current benchmark: • Mass: 1 kt • Gd-loading LS: ~200t • Threshold: (0.1-0.3) MeV • Light yield: ~500 PE/MeV • PMT coverage: up to 80% • Future  (10-50)t detector for • LBNE • Supernova/geo-neutrinos • Mass hierarchy • Precision mixing matrix elements KamLAND Daya Bay Borexino

  30. Liquid scintillator: a mature technology • What we care: light yield, transparency, aging, … • Traditionally 3-grediants, say: • Pseudocumene+MO+fluors • But PC suffer from Low flush point, Chemical attacks, High cost, … • Recently 2-grediants, say: LAB + flour • Even more difficult, load metallic elements, Gd, Nd, In, … into the liquid, Known difficult to be stable Currently produced Gd-loaded liquid scintillators

  31. Gd-Loaded LS production at Daya Bay • Chemical procedures • Procurement of high quality materials & Purification of PPO/Gdcl3/TMHA • Gd-compound production & Gd-LS production good quality and stability Gadolinium Choloride Trimethylhemxanoic Acid Linear Alky Benzene Gd-LS production Equipment tested at IHEP, used at Dayabay Fluor GdCl3 TMHA LAB PPO, bis-MSB Gd (TMHA)3 LS Gd-LAB 0.1% Gd-LS

  32. Precision: DayaBayExperiment • Systematic errors < 0.4% • Multiple detector modules + multiple vetos redundancy • Near site data taking this summer, full data taking next summer

  33. Scintillator purification: Borexino Target for pp solar neutrinos, background is the key Water extraction Vacuum distillation Filtration Nitrogen stripping

  34. Future: ~50kt Liquid Scintillator • DayaBayIIFor • Mass hierarchy • Precision mixing matrix elements • Supernova • geo-neutrinos • LENAFor • Supernova • geo-neutrinos • Protondecays • LBNE • HanohanoFor • Supernova • geo-neutrinos • Protondecays • LBNE

  35. The Daya Bay IIproject Daya Bay Daya Bay II Effects of mass hierarchy can be seen from the reactor neutrino energy spectrum after a Fourier transformation • Other main Scientific goals: • Mixing matrix elements • Supernovae/geo-neutrinos L. Zhan et al., PRD78:111103,2008 L. Zhan et. al., PRD79:073007,2009

  36. Technical challenges：liquidscintillator • A typical detector design(R~30m) requires the scintillator attenuation length > 30m • But typical attenuation length of bulk scintillator materials is 10-20 m • How to improve ? Take the 2-grediants solution LAB + fluor as an example : • Use quantum chemistry calculations to identify structures which absorb visible and UV light • Study removing method Linear- Alkyl- Benzene (C6H5 -R) R&D effort by IHEP & Nanjing Uni.

  37. A common issue: photo detection forlargewater/scintillator/LAr detectorslow cost, single PE, low background,… • Large area, low cost MCP • All (cheap) glass • Anode is silk-screened R&D project by Henry Frisch et al.

  38. Other ideas: high QE PMTs • 20” UBA/SBA photocathode PMT from Hamamatzu ? • New ideas: • Top: transmitted photocathode • Bottom: reflective photocathode • additional QE: ~ 80%*40% • MCP to replace Dynodes  no blocking of photons 5”MCP-PMT made in China • ~ 2 improvement on QE Photocathode MCP Anode Test results: Gain: (1-5)105 Noise: < 10 nA QE~(15-20)% Photocathode R&D effort by Y.F. Wang et al

  39. Sampling detectors for neutrino beams T2K near • Absorber: Pb, Fe, … • Sensitive detectors: Emulsion Films(OPERA), Plastic(MINOS) and Liquid(NOVA) Scintillators, RPC(INO), … • Near detector issues: hybrid detector system to monitor neutrino/muon flux & beam profile OPERA 1.25 kt NOVA 25 kt

  40. Indian Neutrino observatory: INO • 50kt magnetized iron plate interleaved by RPC for • Sign sensitive atmospheric neutrinos (stage I) • long baseline neutrino beams • (stage II) • Features: • Far detector at magic baselines: • CERN to INO: 7152 km • JPARC to INO: 6556 km • RAL to INO: 7653 km • Muons fully contained up to 20 GeV • Good charge resolution, B=1.5 T • Good tracking/Energy/time resolution three 17kt modules, each 161614.4m3 150 iron plates, each 5.6 cm thick

  41. 50-100 m 15 m n beam 50-100kT 15 m B=1 T iron (3 cm) + scintillators (2cm) A Magnetized Iron Neutrino Detector for SuperBeams/neutrino factories(MIND) • Goal: CP phase  appearance of “wrong-sign” muons in magnetised iron calorimeter • A generic detector simulation and R&D, Baseline assumed 2000-7500 km • Detector benchmark: • 50-100 kt Far detector • Features: • Segmentation: 3 cm Fe + 2 cm extruded scintillator + WLS fiber + SiPM • 1 T toroidal magnetic field

  42. Physics reach: ultimate dream

  43. Summary • No significant advances of neutrino physics since the discovery of neutrino oscillation  waiting for q13 • A lot of technological progress  preparation for the next generation experiments • larger mass: typically a factor of 10 for all the techniques • Better resolution, precision, signal to background ratio etc • Innovative ideas • New discoveries ahead of us

  44. Thanks 谢谢 Acknowledgements Many Information & slides from relevant talks given at NuFact2010, Neutrino 2010, WIN11, NeuTEL 2011, etc.

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