Core Insights - The Jiangmen Underground Neutrino Observatory (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][9] - The initial data collected during the trial operation indicates that the key performance indicators of the JUNO detector have met or exceeded design expectations, enabling it to address a significant issue in particle physics: the ordering of neutrino masses [1][9] Group 1 - 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 [2] - Unlike similar international experiments, JUNO's measurement of mass ordering is unaffected by terrestrial material effects and other unknown neutrino oscillation parameters, significantly improving the precision of three out of six neutrino oscillation parameters [2] Group 2 - The JUNO project was proposed by the Institute of High Energy Physics, Chinese Academy of Sciences in 2008, received strategic support in 2013, and began construction of the underground laboratory in 2015 [5] - The laboratory construction was completed in December 2021, and the detector installation began, with the infusion of ultra-pure water and liquid scintillator starting in December 2024 [5] - The project team successfully infused over 60,000 tons of ultra-pure water within 45 days, maintaining a liquid level difference within centimeters and a flow deviation of no more than 0.5%, ensuring the safety and stability of the detector structure [5] Group 3 - The core detector of JUNO has an effective mass of 20,000 tons and is located in a 44-meter deep water pool, featuring a stainless steel mesh shell that supports various critical components, including a 35.4-meter diameter acrylic sphere and numerous photomultiplier tubes [7] - The JUNO project is a major international collaboration led by the Institute of High Energy Physics, involving nearly 700 researchers from 74 institutions across 17 countries and regions [9] - The design lifespan of JUNO is 30 years, with potential upgrades to become the world's most sensitive experiment for neutrinoless double beta decay, which could provide insights into fundamental questions about the nature of matter and the universe [9]

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].

Core Viewpoint - The Jiangmen Neutrino Experiment (JUNO) has successfully completed the filling of 20,000 tons of liquid scintillator and has officially begun data collection, marking a significant milestone in neutrino research and particle physics [3][4]. Group 1: Experiment Overview - JUNO is the first large-scale neutrino experiment of its kind in the world, designed to address fundamental questions about the nature of matter and the universe [3]. - The experiment is located 700 meters underground in Jiangmen, Guangdong Province, and can detect neutrinos from nuclear power plants located 53 kilometers away [4]. - The design lifespan of the JUNO project is 30 years, with potential upgrades to enhance its sensitivity for future experiments [4]. Group 2: Technical Achievements - The initial data collected during the trial operation indicates that the detector's key performance metrics have met or exceeded design expectations [4]. - The experiment aims to resolve significant issues in particle physics, such as the mass ordering of neutrinos, specifically whether the third type of neutrino is heavier than the second [4]. Group 3: International Collaboration - The JUNO project involves collaboration among 700 researchers from 74 institutions across 17 countries and regions, highlighting its international significance [5]. - The success of the experiment is attributed to effective international cooperation, particularly in advancing liquid scintillator detection technology [5]. Group 4: Construction and Technical Requirements - The construction of JUNO required meticulous planning, testing, and adherence to strict material purity and safety standards [6]. - The core detector consists of a 20,000-ton liquid scintillator housed in a 41.1-meter diameter stainless steel structure, equipped with thousands of photomultiplier tubes to detect neutrino interactions [7][8].

Core Insights - The Jiangmen Neutrino Experiment (JUNO) has officially commenced operations, marking the first large-scale neutrino experiment of its kind globally, aimed at addressing fundamental questions about the nature of matter and the universe [1][4]. Group 1: Experiment Overview - The JUNO detector is located 700 meters underground in Jiangmen, Guangdong Province, and is capable of detecting neutrinos from nuclear power plants located 53 kilometers away, with unprecedented precision in measuring their energy spectrum [2][4]. - The experiment has achieved key performance indicators that meet or exceed design expectations, enabling it to tackle significant questions in particle physics, such as the mass ordering of neutrinos [4][6]. Group 2: Technical Specifications - The core detector of JUNO has an effective mass of 20,000 tons of liquid scintillator, housed in a stainless steel structure with a diameter of 41.1 meters, and is equipped with numerous photomultiplier tubes to detect scintillation light produced by neutrino interactions [10][11]. - The project has stringent requirements for the purity, transparency, and low radioactivity of the liquid scintillator, all of which have been successfully met [10]. Group 3: International Collaboration - The JUNO project is a major international collaboration involving 700 researchers from 74 institutions across 17 countries and regions, highlighting the importance of global cooperation in advancing scientific research [6][8]. - The success of the JUNO experiment is attributed to effective international collaboration, particularly in pushing the limits of liquid scintillator detection technology [6]. Group 4: Future Prospects - The design lifespan of the JUNO experiment is projected to be 30 years, with potential upgrades to become the world's most sensitive experiment for neutrinoless double beta decay, which could provide insights into the absolute mass of neutrinos and whether they are Majorana particles [4][5]. - The experiment will significantly enhance the precision of three out of six neutrino oscillation parameters and open new avenues for exploring unknown physics, including searches for sterile neutrinos and proton decay [7].

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed the filling of 20,000 tons of liquid scintillator and has officially begun data collection, marking it as the first large-scale and high-precision neutrino-specific scientific facility in operation globally [1][2] Group 1: Project Overview - The JUNO project was proposed by the Institute of High Energy Physics, Chinese Academy of Sciences in 2008, receiving strategic support in 2013 and commencing construction in 2015 [2] - The detector is located 700 meters underground in Jiangmen, Guangdong Province, and is capable of detecting neutrinos from nuclear power plants located 53 kilometers away [1][2] Group 2: Technical Achievements - The initial data collected during the trial operation indicates that the key performance indicators of the JUNO detector have met or exceeded design expectations, enabling it to address significant questions in particle physics, particularly neutrino mass ordering [1][3] - The detector's design includes a 20,000-ton liquid scintillator and a complex structure with various components, including 20,000 photomultiplier tubes, ensuring high precision in measuring neutrino interactions [3] Group 3: Future Implications - The JUNO experiment has a planned operational lifespan of 30 years and can be upgraded to become the world's most sensitive experiment for neutrinoless double beta decay, which could provide insights into fundamental questions about the universe [3] - The spokesperson for the JUNO collaboration emphasized that the completion of the detector filling and the start of data collection represents a breakthrough in understanding the nature of matter and the universe [3]