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Neutrino detectors : Present and Future Yifang Wang Institute of high energy physics.

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Presentation on theme: "Neutrino detectors : Present and Future Yifang Wang Institute of high energy physics."— Presentation transcript:

1 Neutrino detectors : Present and Future Yifang Wang Institute of high energy physics

2 Neutrino industry

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

4 Selected topics Personnel flavors 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(  23 ): SuperK, INO … – Solar neutrinos(  12 ): SuperK, SNO, Borexino, … – Reactor neutrinos(  12,  13 ): KamLAND, Daya Bay, Double CHOOZ, Reno,…  mass hierarchy – Accelerator neutrinos(  23,  13 ): MINOS, OPERA, MiniBooNe, T2K, NOVA,…  mass hierarchy, , … 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 SM: – m =0   ( e ) = 0 – m  0   ( e ) ~  B Non-SM : –  ( e ) ~  B Astrophysics limit(model dependent) – He star, White dwarf, SN 1987 A, Solar(SuperK, KamLAND, Borexino), … Direct searches: – 1/T excess in -e scattering Bohr magneton  B = e  h / 2 m e TEXONO  1kg ULB-HPGe  Background level:  ~ 1/(day kg KeV)  Threshold:  ~ 10 KeV  Limit:    e ) < 1.3   B (90% CL)

7 GEMMA 1.5 kg HPGe installed 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  decays, 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 to – Reduce the cost to < ~kg/30K $ ? Current status: impurity ~ /cm 3 Resolution: 1.33MeV Working on stability & repeatability

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

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

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  1/T  1 eV – Target mass scales with volume – Promising for m( ) < 0.1 eV Challenges: – Unknown systematics R&D: 1)Detect the RF signal 2)Understand the resolution 3)Measure the energy spectrum of 83m Kr

12 Mare : Bolometer Bolometer:  T = E/C – Phonons: C ~ T 3 (Debye law) at T<< 1K – Event time:  T = E/C e -t/(C/G) – Resolution :  E = (k B T 2 C) 1/2 Similar Techniques used also in  decay and dark matter searches

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

14 Neutrino oscillation experiments Technologies Water Cerenkov detector Liquid Ar TPC Liquid Scintillator detector Sampling detectors for neutrino beams … 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,…

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 – ” 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/  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 Deep-TITAND (10 Mt) TITAND-I 85m  85m  105m  4 = 3 Mt ( 2.2 Mt FV) TITAND-II 4 modules  8.8 Mt (400  SK) 500 kton

20 GADZOOKS & EGADS Gd in water: – GdCl 3 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 e + p  e + + n   s(0.1% Gd) n + p  d +  (2.2 MeV) n + Gd  Gd* +  (8 MeV)

21 Exotic ideas for LBNE Water Cerenkov Calorimeter: – Segmented modules 1  1  10 m 3 – 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 e appearance Time Drift direction Edrift ~ 500 V/cm m.i.p. ionization ~ 6000 e - /mm Scintillation light yield 5000 γ 128 nm  decay at rest

23 ICARUS Successful After 20 years R&D Excellent performance – Tracking:  x,y ~ 1mm,  z ~ 0.4mm – dE/dx: 2.1 MeV/cm – PID by dE/dx vs range – Total energy by charge integration Lessons learned: Impurities (O 2, H 2 O, CO 2 ) should be < 0.1 ppb O 2 equivalent  3 ms lifetime (4.5m E drift = 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 Wire coordinate (8 m) Drift time coordinate (1.4 m) CNGS  CC events in ICARUS T600 ArgoNeut event in NuMI

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) readout wires (128:1 MUX) 3mm Wire pitch

27 o In Japan: 100kt for JPARK  Okinoshima o In Europe: Modular and Glacier o Modular: –20 kton proposal at LNGS based on larger 8x8 m 2 ICARUS modules o Glacier: – kton, Readout: Large GEMs (LEM) Liquid Argon: other proposals LAr Cathode (- HV) E- field Extraction grid Charge readout plane (LEM plane) UV & Cerenkov light readout PMTs E≈ 1 kV/cm E ≈ 3 kV/cm Electron ic racks Field shaping electrodes GAr

28 LBNE: LAr or Water ? Water 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 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 ?

29 Liquid scintillator detectors Successful for reactor and geo- neutrinos Current benchmark: – Mass: 1 kt – Gd-loading LS: ~200t – Threshold: ( ) 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 GroupsSolventComplexant for Gd compound Quantity(t) ChoozIPBalcohol5 Palo VerdePC+MOEHA12 Double ChoozPXE+dodecaneBeta-Dikotonates40 RenoLABTMHV40 Daya BayLABTMHV185 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 Gd-LS production Equipment tested at IHEP, used at Dayabay GdCl3TMHA PPO, bis-MSB LAB Gd (TMHA)3 Gd-LAB LS 0.1% Gd-LS Gadolinium Choloride Trimethylhe mxanoic Acid Linear Alky Benzene Fluor

32 Precision: Daya Bay Experiment 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 LENA For Supernova geo-neutrinos Proton decays LBNE Hanohano For Supernova geo-neutrinos Proton decays LBNE Daya Bay II For Mass hierarchy Precision mixing matrix elements Supernova geo-neutrinos

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

36 Technical challenges : liquid scintillator A typical detector design(R~30m) requires the scintillator attenuation length > 30m But typical attenuation length of bulk scintillator materials is 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 36 R&D effort by IHEP & Nanjing Uni. Linear- Alkyl- Benzene (C 6 H 5 -R)

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

39 Sampling detectors for neutrino beams 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 T2K near

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  14.4m iron plates, each 5.6 cm thick

41 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 km Detector benchmark: – kt Far detector Features: – Segmentation: 3 cm Fe + 2 cm extruded scintillator + WLS fiber + SiPM – 1 T toroidal magnetic field iron (3 cm) + scintillators (2cm) beam 15 m B=1 T kT m

42 Physics reach: ultimate dream

43 Summary No significant advances of neutrino physics since the discovery of neutrino oscillation  waiting for  13 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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