The Jiangmen neutrino experiment is to determine the order of neutrino mass by using the neutrino oscillation in the reactor. It is of great significance for human beings to understand the basic structure of the microscopic matter and the origin and evolution of the macroscopic universe.[1]
Located in Kaiping, Jiangmen, Guangdong Province, the Jiangmen Neutrino Laboratory is a large scientific device jointly built by the Chinese Academy of Sciences and Guangdong Province. Its scientific objectives are to determine the order of neutrino mass, accurately measure neutrino mixing parameters, study supernovae, Earth and solar neutrinos, and find proton decay, inactive neutrinos, etc.[9]
On January 10, 2015, the construction kick-off meeting was held in Jiangmen City, Guangdong Province.This is the second large-scale neutrino experiment hosted by China after the Daya Bay reactor neutrino experiment.
Chinese name
Jiangmen Underground Neutrino Experiment Base
Foreign name
Jiangmen Underground Neutrino Observatory
Experimental institutions
Chinese Academy of Sciences
Experiment purpose
Neutrino mass ordering, accurate oscillation parameters
The experimental station will be built at a depth of 700 meters underground. The experimental station is planned to be built by the end of 2014 and completed by the end of 2019. It is planned to be put into operation and start physical data retrieval in 2020, with at least 20 years of operation.The neutrino detector built in the experiment will be the most energy accurate and large-scale in the worldLiquid scintillator detector。The launch of this experiment marks the transformation of neutrino experimental research in China from starting to spanning.
It is reported that inDaya Bay Neutrino ExperimentAfter the discovery of the third oscillation mode of neutrinos, the next hot target of international neutrino research is to measure the order of neutrino mass.Neutrino has mass, which is the only one with solid experimental evidenceStandard Model of Particle PhysicsThe related research may discover new physical phenomena.The physical sensitivity analysis shows that the best experimental site for this study is located 50~55km away from the reactor and within the same distance from all reactors.
Jiangmen neutrino experiment
Experimental principle
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Figure 1 is the schematic diagram of the neutrino detector in the Jiangmen experiment: the spherical neutrino detector is placed in the center of the pool, and the upper and lower sides are surrounded by more than two meters of water to shield the background.The trace detector is used as the anti coincidence detector at the top of the pool;Place on the inner wall of the poolPhotomultiplier tube(PMT) Detects cosmic rays.The energy resolution of the 20000 ton liquid scintillator detector used in the experiment has reached an unprecedented 3%. The liquid scintillator is the medium for detecting neutrinos.When a large number of neutrinos pass through the detector, they will occasionally react in the detector and emit extremely weak flashing light, which will be detected by the photosensitive device (photomultiplier tube).The liquid scintillator is composed of 99.7% alkyl benzene, which is the main raw material of daily detergent. It has the advantages of non-toxic, easy biodegradation, low fire risk, etc.
Figure 1
Experimental location
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Dashi Mountain in Jinji Town and Chishui Town, Kaiping City, Jiangmen, Guangdong Province.Located at the junction between Yangjiang Nuclear Power Station and Taishan Nuclear Power StationVertical bisectorOn.
Location of Jiangmen Neutrino Experiment
Experiment purpose
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The experiment will build a 20000 tonLiquid scintillator detectorIt is about 53km away from Yangjiang and Taishan reactors, 700m underground, and its energy resolution has reached an unprecedented 3%.By detecting the neutrino energy spectrum from the reactor, accurately measure the oscillation signal of the reactor neutrino to determine the neutrino mass order, accurately measure the four mixing parameters, and study the supernova neutrino, the earth neutrino, the atmospheric neutrinoSolar neutrinoAnd inert neutrinos.
Construction progress
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In July 2019, the construction of Jiangmen neutrino experiment infrastructure entered a critical stage of underground laboratory construction, which is expected to be completed in 2022, and is expected to reveal the mystery of neutrino quality sequence in the future.[2-3]
On December 12, 2020, China's first generation neutrino experimental device, Daya Bay Reactor Neutrino Experiment (Daya Bay Experiment) device, was officially retired after achieving the original scientific goals and completing the scientific mission.
Academician Wang Yifang, the head of Daya Bay Experiment and the director of the Institute of High Energy Physics of the Chinese Academy of Sciences, said that the Jiangmen neutrino experiment is expected to be completed in 2022. It uses the neutrinos produced by the Yangjiang and Taishan nuclear power stations. In the near future, it will open the mystery of the order of neutrino quality, and in the accurate measurement of neutrino oscillation parameters, celestial neutrinos, terrestrial neutrinosInternational leading scientific achievements have been made in search of new physics and research on supernovae.Around 2030, the Jiangmen neutrino experiment can be upgraded to the world's largest neutrino free double beta decay experiment to measure the absolute mass of neutrinos and determine whether its antiparticle is itself.[4]
From October 10 to 12, 2021, the 2021 Strategic Seminar of the High Energy Physics Branch of the Chinese Physical Society was held in Beijing.It was pointed out at the meeting that the Jiangmen neutrino experiment is under construction and will soon start operation in two or three years, which will make our neutrino research take a leading position in the world.[5]
On April 24, 2022, in the underground experimental hall of Jiangmen neutrino experiment, in the 44 meter deep pool, the installation project of the experimental core equipment - the detector with a diameter of 41 meters is being carried out in a tense and orderly manner.[6]
In May 2022, in the Jiangmen Neutrino Experiment Hall, 700 meters underground, the lifting platform installed from top to bottom to realize the installation of the Perspex ball layer by layer has been installed and lifted to 38 meters, which is like a giant "Transformers Tower", preparing for the next installation of the Perspex ball.[7]
In June 2022, the main structure of the Jiangmen neutrino experiment detector will be installed.[8]
