On the morning of December 18th, the construction of the Jiangmen Neutrino Experiment reached its final critical milestone - liquid injection. In the liquid filling room 700 meters underground, Wang Yifang, the project manager of the Jiangmen neutrino experiment and an academician of the CAS Member, announced the "start of infusion". Subsequently, the staff pressed the button, and the water was filtered layer by layer into ultrapure water, which was then injected into the detector pool at a flow rate of 100 tons per hour. Cao Jun, Executive Deputy Manager of the Jiangmen Neutrino Experiment Project and Director of the Institute of High Energy Physics of the Chinese Academy of Sciences, introduced that the liquid infusion will be carried out in two steps. The first two months will fill the inner and outer space of the central detector's plexiglass ball with ultra pure water, and then six months will replace the ultra pure water inside the plexiglass ball with liquid scintillators. It is expected to complete all infusion tasks by August 2025 and begin formal data collection operations. The reporter learned that after the liquid infusion is completed, the hollow "glass ball" in the detector of Jiangmen Neutrino Experiment Center will become a "crystal ball" soaked in ultrapure water and filled with liquid scintillators. The central detector of the Jiangmen Neutrino Experiment is a liquid scintillation detector with an effective mass of 20000 tons, located in the center of a 44 meter deep pool in the underground experimental hall. The main support structure of the detector is a stainless steel mesh shell with a diameter of 41.1 meters, which carries many detector components such as organic glass spheres with a diameter of 35.4 meters, 20000 tons of liquid scintillators, 20000 20 inch photomultiplier tubes, 25000 3-inch photomultiplier tubes, etc. Cao Jun introduced that the photomultiplier tubes covering the inner wall of the central detector can detect the scintillation light generated when neutrinos are "captured" by liquid scintillators, and convert the light signal into an electrical signal output. Compared with the current international best level, the volume of liquid scintillators in the detector of Jiangmen Neutrino Experiment Center has increased by 20 times, the photoelectron yield has increased by 3 times, and the energy resolution has reached an unprecedented 3%. At the same time, the central detector is immersed in a cylindrical pool, which serves as both a water Cherenkov detector and a shielding body. At the top of the pool is a cosmic ray track detector measuring approximately 1000 square meters. The water Cherenkov detector and cosmic ray track detector jointly detect cosmic rays, thereby eliminating their impact on neutrino detection. The water in the pool can also shield the natural radioactivity of rocks and the large amount of secondary particles generated by cosmic rays in nearby rocks. Wang Yifang stated that the Jiangmen Neutrino Experiment aims to measure the mass order of neutrinos as its primary scientific objective, and also conducts other major cutting-edge research. The project team consists of 17 countries and regions, with over 700 members. After the completion of the Jiangmen Neutrino Experiment, it will become one of the international centers for neutrino research, forming a dominant force in neutrino research with the ongoing construction of Japan's top tier Kamioka Neutrino Experiment (Hyper-K) and the United States' Deep Underground Neutrino Experiment (DUNE). China's international leading position in neutrino research will be further consolidated. (New Society)