Introduction of the JUNO experiment Yifang Wang Institute

Introduction of the JUNO experiment Yifang Wang Institute of High Energy Physics Shanghai, May 29, 2014

Neutrino Oscillation Neutrino oscillation: u Ø Ø Ø u Known parameters： 23, 12, DM 223 , DM 212 Recent progress: 13 Unknown parameters: MH(DM 223), Daya Bay: What is next: ð ð 2020/9/15 Neutrino mass hierarchy ? Unitarity of neutrino mixing matrix ？ PRL 112(2014)061801 Θ 23 is maximized ? CP violation in the neutrino mixing matrix as in the case of quarks ? Large enough for the matter-antimatter asymmetry in the Universe ? 2

The JUNO Experiment Daya Bay 60 km Kam. LAND Daya Bay II u u u 20 kton LS detector 3% energy resolution Rich physics possibilities ð ð ð ð Mass hierarchy Precision measurement of 4 mixing parameters Supernovae neutrinos Geoneutrinos Sterile neutrinos Atmospheric neutrinos Exotic searches Talk by Y. F. Wang at ICFA seminar 2008, Neutel 2011; by J. Cao at Nutel 2009, Nu. Turn 2012 ; Paper by L. Zhan, Y. F. Wang, J. Cao, L. J. Wen, PRD 78: 111103, 2008; PRD 79: 073007, 2009

Location of JUNO NPP Daya Bay Status Operational Planned Power 17. 4 GW Huizhou Lufeng Yangjiang Taishan Planned Under construction 17. 4 GW 18. 4 GW 17. 4 GW Overburden ~ 700 m Previous site candidate Kaiping, Jiang Men city, Guangdong Province Guang Zhou 2. 5 h drive Shen Zhu Hai 53 km Huizhou NPP Lufeng NPP Daya Bay NPP Hong Kong Macau 53 km Yangjiang NPP Taishan NPP by 2020: 26. 6 GW 4

The plan: a large LS detector – LS volume: 20 for more statistics (40 events/day) – light(PE) 5 for better resolution (DM 212/ DM 223 ~ 3%) Muon detector Steel Tank 20 kt LS Water seal 20 kt water Acrylic tank：F 34. 5 m Stainless Steel tank ：F 37. 5 m 6 kt MO ~15000 20” PMTs coverage: ~80% 1500 20” VETO PMTs 2020/9/15 5

Mass Hierarchy at Reactors DM 223 L. Zhan et al. , PRD 78: 111103, 2008; PRD 79: 073007, 2009

Optimum baseline for MH • Optimum at the oscillation maximum of 12 • Multiple reactors may cancel the oscillation structure – Baseline difference cannot be more than 500 m q 12 osc. maximum Daya Bay NPP Huizhou NPP Y. F Li et al, PRD 88, 013008 (2013) 53 km Yangjiang NPP Taishan NPP 7

Energy scale can be self-calibrated If we have a residual non-linearity: by introduce a self-calibration(based on DM 2 ee peaks): effects can be corrected and sensitivity is un-affected 2020/9/15 8

Physics Reach Thanks to a large θ 13 For 6 years， u Ideally， The relative measurement can reach a sensitivity of 4 ， while the absolute measurement (with the help of Δm 2 mm ~ 1%) can reach 5 u Due to reactor core distributions, relative measurement can reach a sensitivity of 3 , while the absolute measurement can reach 4 Detector size: 20 kt Energy resolution: 3%/ E Thermal power: 36 GW Y. F. Li et al. , ar. Xiv: 1303. 6733 2020/9/15 9

Precision measurement of mixing parameters u u Fundamental to the Standard Model and beyond Probing the unitarity of UPMNS to ~1% level ! ð Uncertainty from other oscillation parameters and systematic errors, mainly energy scale, are included Current Daya Bay II Dm 212 3% 0. 6% Dm 223 5% 0. 6% sin 2 12 6% 0. 7% sin 2 23 10% N/A sin 2 13 14% 4% ~ 15% Will be more precise than CKM matrix elements !

Supernova neutrinos in Giant LS detector • Less than 20 events observed so far • Assumptions: Possible candidate – Distance: 10 kpc (our Galaxy center) – Energy: 3 1053 erg – Ln the same for all types Estimated numbers of neutrino events in JUNO (preliminary) event spectrum of n-p scattering (preliminary) LS detector vs. Water Cerenkov detectors: much better detection to these correlated events Measure energy spectra & fluxes of almost all types of neutrinos 11

Other Physics with Giant LS detector • Geo-neutrinos – Current results: Kam. LAND: 30± 7 TNU (PRD 88 (2013) 033001) Borexino: 38. 8± 12. 0 TNU (PLB 722 (2013) 295) – Desire to reach an error of 3 TNU: statistically dominant – JUNO: Stephen Dye @Neutrino 2012 • × 10 statistics • Huge reactor neutrino backgrounds • Expectation: ? ± 10% • Solar neutrinos – need LS purification, low threshold – background handling (radioactivity, cosmogenic) • Atmosphere neutrinos • Nucleon Decay • Sterile neutrinos 12

Central Detector u Some basic numbers: ð 20 kt liquid scintillator as the target ð Signal event rate: 40/day ð Backgrounds with 700 m overburden: ü Accidentals(~10%), 9 Li/8 He(<1%), fast neutros(<1%) u A huge detector in a water pool: ð Default option: acrylic tank(D~35 m) + SS structure ð Backup option: SS tank(D~38 m) + acrylic structure + balloon u Issues: ð Engineering: mechanics, safety, lifetime, … ð Physics: cleanness, light collection, … ð Assembly & installation u Design & prototyping underway 13

MC example：Energy Resolution u Based on DYB MC (tuned to data), except ð ð ð JUNO Geometry and 80% photocathode coverage PMT QE from 25% -> 35% Attenuation length (1 m-tube measurement@430 nm) ü ü from 15 m = abs. 30 m + Rayleigh scatt. 30 m to 20 m = abs. 60 m + Rayleigh scatt. 30 m total charge-based energy reconstruction with an ideal vertex reconstruction Uniformly Distributed Events R 3 After vertex-dep. correction

Liquid Scintillator u Requirements & works: ð Low background: No Gd-loading ð Current Choice: LAB+PPO+Bis. MSB ð Long attenuation length: 15 m 30 m ü Improve raw materials ü Improve the production process ü Purification – Distillation, Filtration, Water extraction, Nitrogen stripping… ð Highest light yield：Optimization of fluor concentration u Linear Alky Benzene Atte. L(m) @ 430 nm RAW 14. 2 Vacuum distillation 19. 5 Si. O 2 coloum 18. 6 Al 2 O 3 coloum 22. 3 LAB from Nanjing, Raw Al 2 O 3 coloum 20 25 Other works： ð ð ð Rayleigh scattering length Energy non-linearity Aging Engineering issues: equipment for 20 kt Raw material selection: BKG & purity issues Kam. LAND 15

High QE PMT u Three types of high QE 20” PMTs under development: ð Hammamatzu R 5912 -100 with SBA photocathode ð A new design using MCP: 4 p collection ð Photonics-type PMT u MCP-PMT development: ð Technical issues mostly resolved ð Successful 8” prototypes ð A few 20” prototypes Gain R 591 2 R 5912 - MCP 100 PMT QE@410 nm 25% 35% 25% Rise time 3 ns 3. 4 ns 5 ns SPE Amp. 17 m. V 18 m. V 17 m. V P/V of SPE >2. 5 `2 5. 5 ns 1. 5 ns 3. 5 ns SPE 16 TTS

Muon VETO detector u Top tracker(Opera target tracker) u Tracker support u Water system u Tyvek u PMT support u Water pool liner u Earth magnetic shielding 2020/9/15 17

Readout Electronics and Trigger u u Charge and timing info. from 1 GHz FADC Total No. channel 20, 000 Event rate ~ 50 KHz Charge precision 1 – 100 PE: 0. 1 – 1 PE; 100 -4000 PE: 1 -40 PE Noise 0. 1 PE Timing 0 -2 us: ~ 100 ps Main Choice to be made: in water or on surface An option to have a box in water: Ø Ø Ø ~100 ch. per box Changeable in water Global trigger on surface 18

Civil Construction A 600 m vertical shaft A 1300 m long tunnel(40% slope) A 50 m diameter, 80 m high cavern 19

Layout 20

Dorm Office & control room LS storage, mixing & purification Dorm Un-loading zone Storage Tunnel entrance, Assembly exhibition 21

Current Status & Brief Schedule u u Project approved by CAS for R&D and design Geological survey completed ð Granite rock, tem. ~ 31 o. C, little water u EPC contract signed: ð ð u Engineering design by July Construction work by Nov. Paper work towards the construction: ð Land, environment, safety, … Schedule: Civil preparation： 2013 -2014 Civil construction： 2014 -2017 Detector component production： 2016 -2017 PMT production： 2016 -2019 Detector assembly & installation： 2018 -2019 Filling & data taking： 2020 22

International collaboration u u Proto-collaboration since 2013, meeting every 6 months – Italy, Germany, France, Russia, Czech, US, … – Double Chooz, Borexino, LENA, Daya Bay, Hanohano, OPERA, … Formal collaboration this summer 23

Summary M. Blennow et al. , JHEP 1403 (2014) 028 NOv. A, LBNE: PINGU, INO: 23=40 -50 JUNO: 3%-3. 5% • JUNO is competitive for measuring MH using reactor neutrinos – Independent of the yet-unknown CP phase and 23 • Many other science goals: Ø Precision measurement of Δm 312, θ 12, Δm 212 Ø Geo-, solar, supernova, …, neutrinos • R&D and design on going, project will start soon 24

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