Design and Status of JUNO Hans Th. J. Steiger | Technical University - PowerPoint PPT Presentation

Design and Status of JUNO Hans Th. J. Steiger | Technical University of Munich | Chair for Experimental Astroparticle Physics 16th International Conference on Topics in Astroparticle and Underground Physics| Toyama, Japan | 09/11/2019

The JUNO Project – An Overview J iangmen U nderground N eutrino O bservatory Multi-purpose experiment but with a main focus: Measurement of the Neutrino Mass Ordering using reactor anti-electron neutrinos Neutrinos from two Nuclear Power Plants JUNO Central Detector 26.6 GW th power by 2020 (35.8 GW th final) 20 kt Liquid Scintillator Target

JUNO Collaboration 77 members from 16 countries! Country Institute Country Institute Country Institute Armenia Yerevan Physics Institute China IMP-CAS Germany U. Mainz 632 collaborators Belgium Universite libre de Bruxelles China SYSU Germany U. Tuebingen Brazil PUC China Tsinghua U. Italy INFN Catania Brazil UEL China UCAS Italy INFN di Frascati Chile PCUC China USTC Italy INFN-Ferrara Chile UTFSM China U. of South China Italy INFN-Milano China BISEE China Wu Yi U. Italy INFN-Milano Bicocca China Beijing Normal U. China Wuhan U. Italy INFN-Padova China CAGS China Xi'an JT U. Italy INFN-Perugia China ChongQing University China Xiamen University Italy INFN-Roma 3 China CIAE China Zhengzhou U. Latvia IECS China China DGUT NUDT Pakistan PINSTECH (PAEC) China ECUST Russia China CUG-Beijing INR Moscow China Guangxi U. Russia JINR China ECUT-Nanchang City China Harbin Institute of Technology Czech R. Charles University Russia MSU China IHEP Finland University of Jyvaskyla Slovakia FMPICU China Jilin U. France LAL Orsay Taiwan-China National Chiao-Tung U. China Jinan U. France CENBG Bordeaux Taiwan-China National Taiwan U. China Nanjing U. France CPPM Marseille Taiwan-China National United U. China Nankai U. France IPHC Strasbourg Thailand NARIT China NCEPU France Subatech Nantes Thailand PPRLCU China Pekin U. Germany FZJ-ZEA Thailand SUT China Shandong U. Germany RWTH Aachen U. USA UMD1 China Shanghai JT U. Germany TUM USA UMD2 China IGG-Beijing Germany U. Hamburg USA UC Irvine China Germany FZJ-IKP IGG-Wuhan Three Observers: University of Malaya (Kuala Lumpur), University of Zagreb (Croatia), Yale University (USA)

JUNO physics prospects - neutrino mass ordering and beyond Supernova Neutrinos Diffuse Supernova (burst) Neutrinos 5000 in 10s for 10 kpc ∼ 3 / year Solar Neutrinos Atmospheric Neutrinos ( ∼ 10000 / day) several / day Proton Decay Search Cosmic Muons 𝑞 → 𝐿 + + 𝜑 ∼ 250k / day, <E>=215 GeV Reactor Neutrinos Geo Neutrinos ∼ 60 / day ∼ 1 / day Detailed Talk by Dr. Monica Sisti: JUNO Yellow Book Physics Prospects of the JUNO Experiment arXiv:1507.05613 Session Neutrino 18; 17:20

The Neutrino Mass Ordering 2 = 𝑛 𝑗2 - 𝑛 𝑘2 Δ𝑛 𝑗𝑘 2 = 7.5 × 10 −5 𝑓𝑊 2 Δ𝑛 21 Slow Oscillation! 2 | = 2.4 × 10 −3 𝑓𝑊 2 |Δ𝑛 31 Fast Oscillation! 2 depend The sign and the absolute value of Δ𝑛 31 on the Neutrino Mass Ordering ! Solving the Mass Ordering problem is a key for other open questions in neutrino physics: • 0𝜉𝛾𝛾 decay – Majorana or Dirac neutrinos? • 𝜀 CP in the neutrino sector? • Octant of 𝜄 23 ?

ҧ The Neutrino Mass Ordering 𝑀 𝑀 𝑀 2 2 2 𝜉 𝑓 = 1 − 𝑑𝑝𝑡 4 𝜄 13 𝑡𝑗𝑜 2 2𝜄 12 𝑡𝑗𝑜 2 ∆𝑛 21 4𝐹 − 𝑡𝑗𝑜 2 2𝜄 13 𝑑𝑝𝑡 2 𝜄 12 𝑡𝑗𝑜 2 ∆𝑛 31 4𝐹 + 𝑡𝑗𝑜 2 𝜄 12 𝑡𝑗𝑜 2 ∆𝑛 32 𝑄 𝜉 𝑓 → ҧ 4𝐹 𝑀 𝑀 2 ≪ ∆𝑛 32 ≈ 1 − 𝑑𝑝𝑡 4 𝜄 13 𝑡𝑗𝑜 2 2𝜄 12 𝑡𝑗𝑜 2 ∆𝑛 21 2 4𝐹 − 𝑡𝑗𝑜 2 𝜄 13 𝑡𝑗𝑜 2 ∆𝑛 𝑓𝑓 2 2 𝑔𝑝𝑠 ∆𝑛 12 4𝐹 2 ∆𝑛 𝑓𝑓 Full red line: normal ordering (NO) effective ν -mass-squared difference Dashed blue line: inverted ordering (IO) (beat frequency) 2 = ∆𝑛 32 2 + ∆𝑛 21 2 ∆𝑛 31 With: 2 2 2 NO: ∆𝑛 31 = ∆𝑛 32 + ∆𝑛 21 2 ≪ ∆𝑛 32 2 ∆𝑛 12 2 2 2 IO: ∆𝑛 31 = ∆𝑛 32 − ∆𝑛 21 𝟑 for both orderings! Different beat frequency ∆𝒏 𝒇𝒇

Detection of electron anti-neutrinos Visible Spectrum Flux Contribution Detection via the Inverse Beta Decay (IBD) Golden Channel for the detection of neutrinos • High cross section • Two signal coincidence ( ∼ 236 μs ) ν energy can be reconstructed from e + signal • • Threshold of 1.8 MeV

Requirements for the JUNO Detector Reactor baseline variation: < 0.5 km JUNO site in Jiangmen meets this requirements! Perfect 𝟒% Energy resolution: ~ 𝑭(𝑵𝒇𝑾) Detector Res. This is a crucial parameter! Energy scale uncertainty: Large uncertainties and unknown non-linearity could lead to the wrong mass ordering result! → Meticulous Calibration! → Double calorimetry (small + large PMTs) 𝟒% 𝟔% Statistics: 100 kEvents within 6 years! 𝑺𝒇𝒕 = 𝑺𝒇𝒕 = 𝑭(𝑵𝒇𝑾) 𝑭(𝑵𝒇𝑾) 26.6 GW th reactor power 20 kt detector target ( ∼ 60 Evts. / Day) Minimization of the vetoed volume by precise muon track reconstruction Energy spectrum of the JUNO 𝝋 𝒇 events (Effect of the energy resolution on the expected signal)

Overall Detector Design + Veto Central detector: - Acrylic sphere with liquid scintillator - 17571 large PMTs (20-inch) Top tracker - 25600 small PMTs (3-inch) North chimney - 78% PMT coverage - PMTs in water buffer Water pool Water Cherenkov muon veto: Liquid Scintillator - 2400 20” PMTs 44 m Support structure Ø 35.4 m - 35 ktons ultra-pure water - Efficiency > 95% Acrylic sphere - Radon control → less than 0.2 Bq/m3 Compensation coils: 43.5 m - Earth magnetic field <10% - Necessary for 20” PMTs Experiment Daya Bay Borexino KamLAND JUNO Top tracker: LS Target Mass [t] 8 x 20 ∼ 300 ∼ 1000 20000 - Precision muon tracking ∼ 160 ∼ 500 ∼ 250 ∼ 1200 Collected p.e./MeV - 3 plastic scintillator layers Energy resolution @ 1 MeV ∼ 7.5 % ∼ 5 % ∼ 6% ∼ 3 % - Covering half of the top area

Large PMT array • 15000 MCP-PMTs from NNVT (Northern Night Vision Technology) • 5000 dynode PMTs from Hamamatsu (R12860 HQE) • 17571 PMTs will read out the scintillation light of the Central Detector • In production since 2016 • PMT testing: • Finished for dynode PMTs • ∼ 10000 of 15000 MCP-PMTs already tested Specifications Unit MCP-PMT (NNVT) R12860 Hamamatsu HQE Det. Efficiency (QE*CE) % 26.9% ( new Type: 30.1% ) 28.1% Peak to Valley of SPE 3.5, (>2.8) 3, (>2.5) TTS on the top point ns 12, (<15) 2.7, (<3.5) Rise time / Fall Time ns RT ∼ 2, FT ∼ 12 RT ∼ 5, FT ∼ 9 Anode Dark Count kHz 20, (<30) 10, (<50) After Pulse Rate % 1, (<2) 10, (<15) 238 U: 50 238 U: 400 Radioactivity (glass) ppb 232 Th: 50 232 Th: 400 40 K: 20 40 K: 40

Large PMT testing PMT Testing Containers (all PMTs): • Two testing containers in Capacity: 36 (-5) PMTs per Container Zhongshan (Pan-Asia). • Relative PDE Measurement • 1 fixed & 4 rotating reference PMTs • Four containiers • 1 & 2 operational • 3 & 4 in comissioning • Magnetic shielding: 10% EMF • Climate control systems • Two light sources: • stabilized LED • Picosecond-Laser Light sources used in the testing containers PMT test box with PMT holder Scanning Station (5-10% of PMTs): • Provide non-uniformity measurement of PMT parameters • Study dependence of PMT performance on magnetic field • Provide a tool for precise PMT studies and cross calibration PDE differences (photocathode) PMT in the scanning station

Small PMT array Double calorimetry Always in photon counting mode Less non-linearity : calibration of large PMT array Better dynamic range for high energy signals Arrangement of large and small PMTs JUNO custom design: XP72B22 Higher granularity of the CD QE 24%, Peak / Valley 3.0, TTS 2-5 ns ∼ 200 boxes × 128 PMTs 25600 PMTs in the Central Detector • 2.5% coverage • Provided by HZC Photonics (Hainan, PR China) Can effectively help in: • Muon tracking (+ shower muon calorimetry) • Supernova readout • Solar oscillation parameter measurement Under water box provides supply for 128 PMTs (Prototype already built and successfully tested!)

Liquid scintillator Purification of LAB in 4 Steps: • Solvent: Al 2 O 3 filtration column: improvement of optical properties Linear alkylbenzene • Distillation: removement of heavy metals , improvement of transparence (LAB) as solvent • Water Extraction: removement of radio isotopes from uranium and thorium chain and furthermore of 40 K (underground) • Steam / Nitrogen Stripping: removement of gaseous impurities like Ar, Kr, and Rn (underground) Fluor: Optical Requirements: 2.5 g/l PPO Light output: ∼ 10.000 Photons / MeV → ∼ 1200 p.e. / MeV Attenuation length: > 20 m @ 430 nm Wavelength Required Radiopurity: Shifter: 3 mg/l Bis-MSB Reactor neutrinos: 238 U / 232 Th < 10 -15 g/g, 40 K < 10 -16 g/g Solar neutrinos: 238 U / 232 Th < 10 -17 g/g, 40 K < 10 -18 g/g, 14 C < 10 -18 g/g

Liquid scintillator purification pilot plants (in Daya Bay) Paper Stripping & Distillation Destillation pilot System plants: NIM A 925 (2019) 6, arXiv: 1902.05288 Steam / N2 Stripping Plant LS Storage Tank Al 2 O 3 Water Column Extraction