1 / 19

Neutrino Oscillations from Reactors

Neutrino Oscillations from Reactors. Yifang Wang Institute of High Energy Physics, Beijing JINR, Sep. 19, 2017. I am deeply honored for being awarded the Pontecorvo prize. I met him only once in early 90’s. Although it is before my career on neutrinos, he won all my respects by heart.

mlamm
Télécharger la présentation

Neutrino Oscillations from Reactors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Neutrino Oscillationsfrom Reactors Yifang Wang Institute of High Energy Physics, Beijing JINR, Sep. 19, 2017

  2. I am deeply honored for being awarded the Pontecorvo prize. • I met him only once in early 90’s. Although it is before my career on neutrinos, he won all my respects by heart. • I breathed his air since young, because I was trained in Florence, 80 km from the hometown of Pontecorvo. • One day at Rome in 2003, I encountered his tomb by accident. That was a marvelous feeling. Rome, Cimitero Acattolico JINR， Pontecorvo’s office

  3. Daya Bay: for a New Type of Oscillation Sin22q13 prediction • Fundamental principles • Fundamental parameter • Direction of future neutrino physics: • If q13 is too small，CPV cannot be figured out in the near future n1 n2 n3 q12Solar n Oscillation q13 ? q23 Atm. n Oscillation

  4. Reactor Experiments: comparing observed/expected neutrinos Precision of past experiments，typically 3-6% • Reactor power: ~ 1% • Spectrum: ~ 0.3% • Fission rate: 2% • Backgrounds: ~1-3% • Target mass: ~1-2% • Efficiency: ~ 2-3% Pee  1 sin22q13sin2 (1.27Dm213L/E)  cos4q13sin22q12sin2 (1.27Dm212L/E)

  5. Daya Bay Experiment: Layout • Relative measurement to cancel Corr. Syst. Err. • 2 near sites, 1 far site • Multiple AD modules at each site to reduce Uncorr. Syst. Err. • Far: 4 modules，near: 2 modules • Multiple muon detectors to reduce veto eff. uncertainties • Water Cherenkov： 2 layers • RPC： 4 layers at the top +telescopes Redundancy !!! Cross check; Reduce errors by 1/N

  6. Successful Launch of the Daya Bay Experiment Opening ceremony：Oct. 2007 Aug. 2003: Experimental plan and the detector design is proposed 2006: Project approved in China, and afterwards in other countries Oct. 2007: Civil construction started Dec.2010: All the blasting for the tunnel and underground hall completed 2008-2011: Detector construction, assembly and installation Aug. 2011: Near detector data taking started Dec. 2011: Far detector data taking started  full detector data taking

  7. Tunnel and Underground Lab • Tunnel: ~ 3100m • 3Exp. hall • 1hall for LS • 1hall for water A total of ~ 3000 blasting right next reactors. No one exceeds safety limit set by National Nuclear Safety Agency（0.007g）

  8. Detector Assembly SSV Bottomreflector 4m AV Topreflector PMT 3m AV SSV lid Leak check ACU

  9. Water Cerenkov Detector Installation PermaFlex painting PMT frame & Tyvek Completed pool Install AD Pool with water Cover

  10. A New Type of Oscillation Discovered • Electron anti-neutrino disappearance: R = 0.940 ±0.011 (stat) ±0.004 (syst) announced on Mar. 8, 2012 Sin22q13 = 0.092  0.016(stat)  0.005(syst) c2/NDF = 4.26/4, 5.2 σ for non-zero θ13 F.P. An et al., Phys. Rev. Lett. 108, (2012) 171803; citation > 1300

  11. Update and Prospects • sin22q13 Precision improved from ~ 20%to ~ 4% • Continue to operate until 2020, precision expected: ~ 3% • Combined with T2K & Nova, CP Phase is estimated to be ~ -90o, 2s for CPV

  12. The JUNO Experiment Daya Bay JUNO Overburden ~ 700 m Previous site candidate Kaiping, Jiang Men city, Guangdong Province Guang Zhou 2.5 h drive LufengNPP Shen Zhen HuizhouNPP Daya Bay NPP Zhu Hai Hong Kong Macau 53 km 53 km TaishanNPP Yangjiang NPP by 2020: 26.6 GW

  13. Mass Hierarchy • Oscillation parameters • Supernova neutrinos • Geo-neutrinos • Solar neutrinos • Double beta decays JUNODetector and Challenges • Largest LS detector   20 KamLAND，  40 Borexino • Highest light yield  2 Borexino，  5 KamLAND • Hugh cavern: • ~ 48m 70m • Largest Acrylic tank: • F 35.4m( 13m@SNO) • 20 kt LS • Best attenuation length: 25m (15m @ Daya Bay) • 2000020” PMT • Highest photon detection efficiency : 30%*100% = 30%（25%*60%=15% @ SuperK） 44.5m 43.5m

  14. Challenge I：Central Detector • A huge acrylic tank: • R&D and design completed, contract signed • Acrylic sheets: 9m  3m 12 cm with backgrounds < 1 ppt • thermally shaped to form a sphere • Bonding and precision control • Supporting nodes • A SS structure to hold the acrylic tank and to mount PMTs • Design completed, bidding process finished, contract will be signed soon. • Precision control, PMT installation,… • Issues: tem. change, earthquake, Assembly & installation within in a year on a huge platform

  15. Challenge II: Liquid Scintillator • Current Choice: LAB+PPO+BisMSB • Requirements: • Long attenuation length: 15m  ~30m • Radio-purity: < 10-15 g/g • Engineering issues: Equipment & handling for 20kt • R&D Progress • Transparancy • Improve raw materials • Improve the production process • Purification • Distillation, Filtration, Water extraction, … • High light yield：Optimization of PPO & BisMSB concentration • Radiopurity • Purification • Distillation, Water extraction, Nitrogen stripping… Successful prototype at 20 t level Radiopurity ~ a few 10-15 g/g

  16. Challenge III: Photomultipliers • Large area, High QE, low cost PMT is a must • Available from Hamamatsu for SuperK: QE(25%)*CE(60%) = 15% • Efforts started in 2009 to develop MCP-PMTs in China (NNVT, XIOPM and others), with a goal of QE > 35% at a reasonable cost • Successful development over 6 years • Contract signed(based on quality, availability, cost, risk etc.) • NNVT: 15000, QE(27%)*CE(100%) > 27% • Hamamatsu: 5000, QE(30%)*CE(90%) > 27% Production： QE*CE*Area= 29.1%

  17. JUNO Collaboration 550 collaborators from 71 institutions in 17 countries and regions

  18. JINR was a funding member of the Daya Bay experiment • Great contributions to the liquid scintillator development, cosmic-ray veto detectors, software and data analysis, as well as a number of important physics papers • JINR is again a funding member of the JUNO experiment, committed to cosmic-ray veto detector, PMT testing, intelligent HV power supply, electronics, software and physics preparation • The Pontecoevo prize is a great honor not only to me, but also to the JINR team, and the whole Daya Bay collaboration

  19. Summary • Reactor is a powerful man-made neutrino source for free • If not too far, more powerful than solar, atmospheric, and accelerator neutrinos • Great achievements: discovery of neutrinos, q12, q13 • Great future: • mass hierarchy • Precise measurement of all mixing parameters, unitarity test

More Related