中国地下700米，有了个全球第一

Core Viewpoint - The Jiangmen Neutrino Experiment (JUNO) has successfully completed the infusion of 20,000 tons of liquid scintillator and has officially begun data collection, marking it as the first operational large-scale and high-precision neutrino-specific scientific facility in the world [1][10]. Group 1: Experiment Overview - The JUNO detector is located 700 meters underground near Jiangmen, Guangdong Province, and can detect neutrinos produced by the Taishan and Yangjiang nuclear power plants, measuring their energy spectrum with unprecedented precision [3]. - The experiment aims to address a significant issue in particle physics over the next decade: the ordering of neutrino masses, and will assist scientists in conducting cutting-edge research on neutrinos from the sun, supernovae, atmosphere, and Earth [1][9]. Group 2: Construction and Technical Details - The JUNO project was proposed by the Institute of High Energy Physics, Chinese Academy of Sciences in 2008, received support in 2013, and began construction in 2015. The laboratory was completed in December 2021, with the detector installation starting thereafter [5]. - The infusion process involved over 60,000 tons of ultra-pure water completed in 45 days, with strict control over liquid levels and flow deviations, ensuring the safety and stability of the detector structure [5]. - The core detector, with an effective mass of 20,000 tons, is housed in a 44-meter deep pool and consists of a 35.4-meter diameter acrylic sphere, 20,000 20-inch photomultiplier tubes, and 25,000 3-inch photomultiplier tubes [7]. Group 3: Future Prospects - The JUNO experiment is a major international collaboration involving nearly 700 researchers from 74 institutions across 17 countries and regions, with a design lifespan of 30 years [9]. - Future upgrades could transform JUNO into the world's most sensitive experiment for neutrinoless double beta decay, potentially answering fundamental questions about the nature of neutrinos and the universe [9].