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]