As a scientific researcher, Wu Jianhua has been talking a lot recently.
Rumors are circulating Chinese Academy of Sciences The neutrino laboratory 700 meters underground in Kaiping, Jiangmen, Guangdong, injected 20,000 tons of water on June 27. After that, people can no longer see the neutrino trap with the naked eye. "The most important weapon of the country".
Therefore, starting from the beginning of June, more and more people came to visit, and Wu Jianhua needed to introduce what they were doing to the visitors.
A sphere that captures neutrinos. Photographed by a reporter from Times Weekly.
"Neutrino", a word with high technological purity, is popular in Kaiping, a city with watchtowers, sefen, overseas Chinese hometowns and Magang geese as the main stories. Here, it seems a little out of place, but it is also extremely harmonious.
Wu Jianhua is the on-site supervisor of this experimental project office. This young man from Heze, Shandong began to participate in this experiment after graduating from with a PhD in from the Chinese Academy of Sciences.
He said that many people from Institute of High Energy, Chinese Academy of Sciences have lived in this little-known place for many years. As a northerner, it is not surprising that he knows very little about Kaiping, just as the world is equally unfamiliar with neutrinos. There is another rumor in the market - if China wins the Nobel Prize in Physics in the next few years, the most likely candidate will be the neutrino experiment in this mountain valley.
Wu Jianhua smiled, "Although it depends on luck, it is not impossible."
article | Li Guang
This article is reprinted from the WeChat public account "Duchengji Studio" (ID: DUCHENGJIPLUS) under Times Weekly. The original article was first published on June 30, 2022. The original title was "Guangdong's Deepest Buried Secret: In "700 Meters Underground" does not represent the views of Outlook Think Tank .
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How to reach 700 meters underground
CCTV mentioned in the recent Greater Bay Area live broadcast that the neutrino experiment in Kaiping is an important weapon of the country. According to the introduction of
at the Institute of High Energy Physics, Chinese Academy of Sciences, this experiment was established in 2013 and the infrastructure construction started in early 2015. It has been nearly ten years, but in Guangdong, its reputation does not seem to match its status.
"In fact, compared with Guizhou's Sky Eye, Guangdong's neutrino experiment is both a scientific research device. Guizhou's Sky Eye is famous, and in fact the neutrino experiment is not inferior."
This statement is consistent with Wu's statement. Scientific workers like Jianhua don't show off or force themselves, they just do their job quietly.
"We do plan to stop opening to the outside world after June 27, so everyone knows the news and rushes to visit before then. However, this will also help us popularize scientific knowledge, which is a good thing."
But you have to go into the underground 700 Mi's neutrino laboratory cannot be completed with just two feet. To enter the largest underground experimental cavern in the country,
needs to take a small train dragged by a winch cable, slide along the 1,266-meter inclined shaft tunnel, and slide down to a depth of 700 meters underground.
Take a small train to a depth of 700 meters underground. Photographed by a reporter from Times Weekly
People who stand on the flat section of the inclined shaft for the first time will start to get lost from here - it is like being in an underground maze, and the lights underground are also different in light and dark. There's even a mottled-painted bulldozer parked in the aisle.
When entering the experimental hall, it is like standing on the edge of a bucket with a depth of 71 meters and a span of 49.5 meters. There is a huge steel structure sphere in the middle of the "bucket".
Wu Jianhua told reporters that the stainless steel structure dome will be completed on June 22. Next, a plexiglass ball will be installed inside the sphere. The plexiglass ball and capturer (photomultiplier tube) and other equipment will be installed. , it is time to start filling the "bucket" and "ball" with water.
"So the rumored news about water filling on the 27th is wrong. From that day onwards we will make plexiglass balls. This construction process requires much stricter cleanliness requirements for the installation environment than steel structures, especially for plexiglass During the polymerization annealing process, dust may affect the installation quality, so we need to minimize human interference as much as possible."
Partial photos of the neutrino sphere captured by a reporter from Time Weekly
It can be understood that the construction is over. There is nothing to see in the entire experimental hall except a sealed steel bucket, so the purpose of visiting before June 27 is to see A ball.
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Nuclear power plant neutrino catcher
This ball is the core of the entire neutrino experiment. Everything that happens in this ball in the future may be a key to unlocking the mystery of the universe.
The so-called neutrino. There are actually three types, which account for a quarter of the 12 most basic particles that make up the material world.
It is very strange. It has no charge when walking, and its weight is only one millionth of that of an electron. It moves at close to the speed of light. The core. Radiation can only be regarded as a "little brother" in front of it - nuclear radiation particles can only travel 10 centimeters in pure lead material (so people use lead to shield nuclear radiation)
but neutrinos can travel carelessly instantaneously. The penetration ability is amazing, and it is harmless to the human body.
In addition to the constant release of neutrinos from the sun, other stars, including the earth, and even humans will release them. However, these scattered releases are not as stable as nuclear power during the fission process. Another characteristic of neutrinos is that they oscillate during propagation. The oscillation effect of neutrinos from the reactor is most obvious at 50-55 kilometers.
"Our location is in the area of Jinji Town and Chishui Town. At the foot of Dashi Mountain, we are 53 kilometers away from the two nuclear power plants in Taishan, Guangdong and Yangjiang, so the neutrinos released by the two nuclear power plants will theoretically oscillate at our location. "
Neutrino traps under construction. Photographed by Times Weekly reporter
When the stable neutrino beams from two nuclear power plants spread here and oscillate, this is the best capture and observation point, while it is buried 700 meters deep underground
Wu Jianhua explained that the "water injection" understood by the outside world is indeed correct, because different water is indeed injected into the "bucket" and the sphere respectively. "The outer layer is ultra-pure. Water can detect neutrinos and can also be used to shield other interference signals. The glass sphere is filled with liquid scintillation water. If neutrinos react in this liquid, fluorescence will appear. Therefore, the densely packed photomultiplier tubes outside the sphere will capture these low lights, pulse the optical signals into electrical signals, and save them in the data acquisition system, providing them to physicists for neutrino analysis and research. "
Photomultiplier tube Photo multiplier reporter from Times Weekly
This working logic of the neutrino experiment means that no light can enter the inside of the experimental ball after the experiment starts. This is the fundamental reason why the ball cannot be seen in the future. Logic.
But this is not wrong.
After all, the little bit of light that appears here in the future is related to the stars and the sea. Any artificial light source or even any dust brought by it will bring errors to the unsolved mysteries of the universe.
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What will the next Nobel neutrino experiment bring? The answer may be that it is not clear.
"It will not be as important to human society as the discovery of fission or atoms and neutrinos. , but it could be a key to our understanding of the origins of the universe. For example, when we study the universe, some energy cannot be found, so what does this energy do? These energies may be related to neutrinos. "
The big bang theory of the universe believes that the explosion occurred at a point. After the explosion, if the positive antimatter are equal in amount, the point will be surrounded by a chaotic energy body, and chaotic things will not be able to evolve into the galaxies or galaxies we see. Planet.
Part of the neutrino trap. Photographed by Times reporter
Therefore, those who study neutrinos believe that neutrinos broke the balance of the Big Bang, which caused the universe to form planets during its subsequent outward expansion. , galaxies and other materials visible to the naked eye.
Whether it is neutrinos or cosmic detection, it is basic research in the field of science.
Wu Jianhua told reporters that this project is similar to Guizhou's "Sky Eye" and can only study the matter itself first. What is its nature? As for how to master and utilize it in the future, we can only talk about it later.Since the discovery of
neutrinos in 1956, four physicists of different nationalities have won the Nobel Prize in Physics in this field, but the huge team and national strength behind an Nobel Prize winner are often What everyone ignores is, "It would be great if the project manager could be promoted to the Nobel Prize, but it still depends on luck."
Returning to the ground from underground. Photographed by a Times Weekly reporter
It takes 15 minutes to return to the ground from 700 meters underground. Between the distance and In addition to time, this has another meaning: it is the passage between Jiangmen Kaiping Diaolou, the hometown of overseas Chinese, Magang Goose, the hometown of architecture and the Big Bang of the universe; it is the KPI of secular society and the mystery of the disappearance of antimatter. aisle.
In the next step, the neutrino experiment will also drive Jiangmen 's science and technology industry. In addition to building a neutrino science and technology popularization exhibition hall, it will also build an international science town. The local government plans to build it into the back garden of the Chinese Academy of Sciences and a new The branch, science and technology release center and international exhibition center will also drive the local construction of a scientific research and innovation city to attract high-end talents.
, the deepest secret in Guangdong, is located 700 meters underground in Kaiping, Jiangmen. html Above 1,700 meters, there is the wind, rain and loneliness in the world, as well as the vicissitudes of the land of Kaiping. 700 meters below is the rainbow and encounter in heaven, the romance and expectations of scientific researchers looking up at the stars.
Fireworks on earth and the sea of stars, I didn’t expect to meet here unexpectedly.
