Overview of neutrino experiment in the Daya Bay era

Neutrino detectorsPresent and FutureYifang WangInstitute of high energy physicsNeutrino industry

Neutrino physicsproblems and methodsMassGeologyAstronomyDirac/MajoranaOscillation/sterile neutrinosMagnetic momentsCosmologyReactorEarthSolarAtmos-phericAcceleratorRadioactive sourcesAstro-objects Relic-neutrinoLiquid scintillatorSemiconductor/crystals/gaseous/scintillatorEmulsionNuclear chemistryWater CerenkovSampling detectorLiquid Argon3Selected topicsPersonnel flavorsMainly on neutrino oscillationsPresent experimental techniques with future prospectsFuture trends

I apologize for incompleteness, bias and mis-handling Selected Neutrino ExperimentsBasic properties of neutrinosMagnetic 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, Daya Bay, Double CHOOZ, Reno, mass hierarchyAccelerator neutrinos(q23,q13): MINOS, OPERA, MiniBooNe, T2K, NOVA, mass hierarchy, d, Neutrino astronomy & applicationsSupernova in combination with solar/atmospheric/reactor neutrinosGeo-neutrinos in combination with solar/reactor neutrinosHigh energy neutrinos(not covered in this talk)Neutrino magnetic momentsSM: mn=0 mn(ne) = 0mn0 mn(ne) ~ 10-19 mBNon-SMmn(ne) ~ 10-10-14 mB Astrophysics limit(model dependent)He star, White dwarf, SN 1987 A, Solar(SuperK, KamLAND, Borexino), Direct searches: 1/T excess in n-e scattering

Bohr magneton B = eh / 2 me

TEXONO1kg ULB-HPGeBackground level: ~ 1/(day kg KeV)Threshold: ~ 10 KeVLimit: mn(ne) < 1.3 10-10 mB (90% CL)GEMMA1.5 kg HPGe installed within NaI active shielding. Multi-layer passive shielding : electrolytic copper, borated polyethylene and leadMore HpGe, better shielding Another fact of 10 ?

[Phys. of At. Nucl.,67(2004)1948]

Ultra-pure Ge detectorsCommon technology for bb 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 10-13Reduce the cost to < ~kg/30K $ ?

Current status:impurity ~ 10-11/cm3Resolution: 1.76KeV @ 1.33MeVWorking on stability & repeatability

Absolute Neutrino massb decaysRequirement: Source: Low endpointHigh event rate appropriate lifetimeEnough source material (thickness affect b spectrum)Detector:High resolutionLow background Experiments:Source detector: Katrin, Project 8Source = detector: Mare

Katrin: b spectrometer

Magnetic Adiabatic Collimation + Electrostatic FilterA large spectrometer Sensitivity increase with area Low statistics for relevant eventsResolution: ~ 1 eV Sensitivity @ 90%CL: m(n) < 0.2 eV Last such exp. ? T1/2 = 12.3 yProject 8: Radio Frequency Electrons moving in a uniform magnetic field emit cyclotron radiation:

Advantages: Non-destructive measurement of Frequency energyResolution improves over time Dw 1/T 1 eVTarget mass scales with volumePromising for m(n) < 0.1 eV Challenges: Unknown systematics

R&D: Detect the RF signalUnderstand the resolution Measure the energy spectrum of 83m KrMare Bolometer Bolometer: DT = E/CPhonons: C ~ T3 (Debye law) at T 80 mVolume: 100 days to fill, > 20 days to circulate 1 volumeCivilA cavern of 55m diameter, 70m high

Not trivial but also not impossiblePhysics reach

Performance Similar for 30kt liquid Ar TPCEven larger water detectors for LBNE, proton decays and supernova

Deep-TITAND (10 Mt)TITAND-I85m 85m105m4 = 3 Mt 2.2 Mt FV)TITAND-II4 modules 8.8 Mt(400 SK)500 ktonGADZOOKS & EGADSGd in water: GdCl3 highly soluble in waterImprove low energy detection capabilitiesflavor sensitiveGood for LBNE, supernova, reactor and geo-neutrinos, A 200 ton-scale R&D project, EGADS is under construction at Kamioka

ne + p e+ + n t 28 ms(0.1% Gd)n + p d + g (2.2 MeV)n + Gd Gd* + g (8 MeV)

Exotic ideas for LBNEWater Cerenkov Calorimeter: Segmented modules 1 1 10 m3 two PMTs at each endPattern recognition similar to crystal calorimeter

Y.F. Wang , NIM. A503(2003)141M.J. Chen et al., NIM. A562 (2006)214

Liquid Ar TPC: another detector candidate for LBNEIdea first proposed in 1985Dense target ample Ionization & scintillation: good energy resolution & Low thresholdExcellent tracking and PID capabilities Digital bubble chamber: Excellent for discoveries, say ne appearance

TimeDrift directionEdrift ~ 500 V/cmm.i.p. ionization ~ 6000 e-/mmScintillation light yield 5000 /mm @ 128 nm

m decay at restICARUSSuccessful After 20 years R&DExcellent performanceTracking: sx,y ~ 1mm, sz ~ 0.4mmdE/dx: 2.1 MeV/cmPID by dE/dx vs rangeTotal 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:(E)/E = 11% / E(MeV)+2%Electromagnetic showers:(E)/E = 3% / E(GeV)Hadron shower (pure LAr):(E)/E 30% / E(GeV)Successful R&D in Europe, Japan & US

Collection viewWire coordinate (8 m)Drift time coordinate (1.4 m)

CNGS nm CC events in ICARUS T600

ArgoNeut event in NuMI

250L@KEKR&D towards LBNE & MicroBooNER&D efforts and technical challengesLong-drift operations(LAr purity)Membrane cryostat for multi-kiloton TPC Readout wires or Large electron MultipliersCold electronics MicroBooNE: Combine R&D with physics A ~100t LAr TPC at Fermilab on-axis Booster beam and off-axis NuMI beam forMiniBooNE low energy excessLow energy cross sections

Future: LBNE LAr option

220kt cryostatMaximum drift length: 2.5 m (1.4 ms) 645000 readout wires (128:1 MUX)3mm Wire pitch In Japan: 100kt for JPARK OkinoshimaIn Europe: Modular and Glacier Modular:20 kton proposal at LNGS based on larger 8x8 m2 ICARUS modulesGlacier:50-100 kton, Readout: Large GEMs (LEM)

Liquid Argon: other proposals

LArCathode (- HV)E-fieldExtraction gridCharge readout plane(LEM plane)UV & Cerenkov light readout PMTs E 1 kV/cmE 3 kV/cmElectronic racksField shaping electrodesGAr

LBNE: LAr or Water Water Pros Proven technologyCost under controlGood energy resolution (slight worse) Good PID & pattern recognition, particularly at low energiesConsLower efficiencyLarger cavern and deep underground

LArProsBeautiful image of eventsGood energy resolution Good PID and pattern recognition High efficiencyRequiring smaller cavern and shallow depth Cons Technology for such a volume ?Huge No. of channels Cost ?

Liquid scintillator detectorsSuccessful for reactor and geo-neutrinosCurrent benchmark: Mass: 1 kt Gd-loading LS: ~200t Threshold: (0.1-0.3) MeVLight yield: ~500 PE/MeVPMT coverage: up to 80%Future (10-50)t detector for LBNESupernova/geo-neutrinosMass hierarchyPrecision mixing matrix elements

KamLANDDaya BayBorexinoLiquid scintillator: a mature technologyWhat we care: light yield, transparency, aging, Traditionally 3-grediants, say:Pseudocumene+MO+fluorsBut PC suffer from Low flush point, Chemical attacks, High cost, Recently 2-grediants, say: LAB + flourEven more difficult, load metallic elements, Gd, Nd, In, into the liquid, Known difficult to be stable

GroupsSolvent Complexant for Gd compound Quantity(t)ChoozIPBalcohol 5Palo Verde PC+MOEHA12Double ChoozPXE+dodecaneBeta-Dikotonates40RenoLABTMHV40Daya BayLABTMHV185Currently produced Gd-loaded liquid scintillators Gd-Loaded LS production at Daya BayChemical proceduresProcurement of high quality materials & Purification of PPO/Gdcl3/TMHAGd-compound production & Gd-LS production

good quality and stability Gd-LS production Equipmenttested at IHEP, used at Dayabay GdCl3TMHAPPO, bis-MSBLABGd (TMHA)3Gd-LABLS0.1% Gd-LSGadolinium CholorideTrimethylhemxanoic AcidLinear Alky BenzeneFluorPrecision: Daya Bay ExperimentSystematic errors < 0.4%Multiple detector modules + multiple vetos redundancy Near site data taking this summer, full data taking next summer

Scintillator purification: BorexinoTarget for pp solar neutrinos, background is the key

Water extractionVacuum distillationFiltrationNitrogen stripping

Future: ~50kt Liquid Scintillator

LENA For Supernovageo-neutrinosProton decaysLBNEHanohano For Supernovageo-neutrinosProton decaysLBNE Daya Bay II For Mass hierarchyPrecision mixing matrix elementsSupernovageo-neutrinosThe Daya Bay II project

Daya BayDaya Bay IIOther main Scientific goals: Mixing matrix elementsSupernovae/geo-neutrinos

L. Zhan et al., PRD78:111103,2008Effects of mass hierarchy can be seen from the reactor neutrino energy spectrum after a Fourier transformationL. Zhan et. al., PRD79:073007,200935Technical challengesliquid scintillatorA typical detector design(R~30m) requires the scintillator attenuation length > 30mBut typical attenuation length of bulk scintillator materials is 10-20 mHow to improve ? Take the 2-grediants solution LAB + fluor as an example : Use quantum chemistry calculations to identify structures which absorb visible and UV lightStudy removing method

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R&D effort by IHEP & Nanjing Uni.Linear- Alkyl- Benzene (C6H5 -R) A common issue: photo detection for large water/scintillator/LAr detectorslow cost, single PE, low background,Large area, low cost MCP

All (cheap) glassAnode is silk-screenedR&D project by Henry Frisch et al.Top: transmitted photocathodeBottom: reflective photocathode additional QE: ~ 80%*40%MCP to replace Dynodes no blocking of photonsOther ideas: high QE PMTs~ 2 improvement on QE

5MCP-PMT made in China

Test results: Gain: (1-5)105 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 alSampling detectors for neutrino beamsAbsorber: 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

OPERA1.25 ktNOVA25 ktT2K nearIndian Neutrino observatory: INO50kt 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 kmJPARC to INO: 6556 kmRAL to INO: 7653 kmMuons fully contained up to 20 GeVGood charge resolution, B=1.5 TGood tracking/Energy/time resolution

three 17kt modules, each 161614.4m3150 iron plates, each 5.6 cm thickA Magnetized Iron Neutrino Detector for SuperBeams/neutrino factories(MIND)Goal: CP phase appearance of wrong-sign muons in magnetised iron calorimeterA generic detector simulation and R&D, Baseline assumed 2000-7500 kmDetector benchmark:50-100 kt Far detectorFeatures:Segmentation: 3 cm Fe + 2 cm extruded scintillator + WLS fiber + SiPM1 T toroidal magnetic field

iron (3 cm)+ scintillators (2cm)n beam15 m15 mB=1 T50-100kT50-100 m

Physics reach: ultimate dream

SummaryNo significant advances of neutrino physics since the discovery of neutrino oscillation waiting for q13A lot of technological progress preparation for the next generation experiments larger mass: typically a factor of 10 for all the techniquesBetter resolution, precision, signal to background ratio etcInnovative ideas New discoveries ahead of usThanks Acknowledgements Many Information & slides from relevant talks given at NuFact2010, Neutrino 2010, WIN11, NeuTEL 2011, etc.

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