Please accept New Year's greetings from the world's deepest underground laboratory!

◎ Science and Technology Daily reporter Zhang Gailun

Jing Mingkun, born in the 1990s, has been working in China Jinping Underground Laboratory for nearly seven years.

After graduating from Chengdu University of Technology, he joined the laboratory deep in the mountains and became a research assistant for the Jinping Laboratory project at Tsinghua University. This was a job that Jing Mingkun "did not even dare to think about" when he was in college - searching for dark matter with researchers in a major national scientific and technological infrastructure.

Jinping Dam.

Image source: China Jinping Underground Laboratory official website

Finding dark matter is demanding. We live in the background noise of cosmic rays, and different particles make different sounds. But dark matter makes almost no sound.

China Jinping Underground Laboratory provides a sufficiently quiet environment. Located in the middle of Jinping Mountain Traffic Tunnel in Liangshan Yi Autonomous Prefecture, Sichuan Province, it is currently the underground laboratory with the lowest cosmic ray flux in the world and the underground laboratory with the deepest rock coverage in the world.

Here, researchers try to block out all known noises and create ears sensitive enough to hear the whispers of dark matter.

Jing Mingkun's daily work is to detect the radiation background of various samples. In fact, each material has its own radiation, that is, its own noise. Recently, the workload has been quite heavy. China Jinping Underground Laboratory is "expanding", and various building materials continue to be delivered to Jing Mingkun: cement, steel bars, bricks... Each one must pass the inspection before it can be officially put into laboratory construction.

In December, Jing Mingkun tested 110 samples of materials. Each sample took about three hours to measure, and he spent more than 10 hours in the laboratory every day.

Jing Mingkun is already familiar with the testing process: get the sample material, stir it until it is uniform, put it into the sample box, fill it up and compact it; put it into the instrument to measure the basic data. When the instrument is working, Jing Mingkun drafts a report on the computer; then, extract the key information from the energy spectrum given by the instrument, perform simulation calculations, and get the final value; compare the value with the benchmark value to determine whether the material is qualified.

In 2021, Jing Mingkun lived in the mountains for 10 months. His life was simple enough, basically going from dormitory to canteen to laboratory, and he liked this state.

Extremely deep underground and extremely low radiation background frontier physics experimental facility (Jinping large facility).

Image source: China Jinping Underground Laboratory official website

My relationship with Jinping started from an “accompaniment” experience.

In April 2015, Jing Mingkun was about to graduate, and he had found a job in his hometown of Mianyang, Sichuan. At that time, his classmates saw the recruitment notice of China Jinping Underground Laboratory and asked him to go with them to "take a look". "I have never been to Liangshan, and I had nothing to do before graduation, so I went there as a trip." Jing Mingkun and his classmates first went to Xichang, and then took a two-hour car ride to "visit" Jinping Underground Laboratory.

Afterwards, like all stories related to "accompanying students to take exams", the classmates did not choose Jinping, but Jing Mingkun decided to stay.

This job obviously did not satisfy Jing Mingkun's need to be "close to home". It would take more than ten hours to travel from Xichang to Mianyang by train.

But Jing Mingkun felt that it was suitable for him. His undergraduate major was nuclear engineering and technology, which was a good match for his major. His job was also "high-end", and his parents said that this was a contribution to the country. Jing Mingkun did not like to deal with too many people and preferred to be alone. In Jinping, he, a planet that liked to rotate alone, had found a vast universe that could accommodate him.

In fact, there are many people working for the China Jinping Underground Laboratory. There are scientific researchers, field staff, engineering management personnel and administrative teams... At the beginning of the construction of the laboratory, it was a cooperative project between Tsinghua University and Yalong River Basin Hydropower Development Co., Ltd. In 2019, the construction of a major national scientific and technological infrastructure project was officially launched, and the China Jinping Underground Laboratory became a national platform. Now, Yalong River Basin Hydropower Development Co., Ltd. has established the Jinping Underground Laboratory Management Bureau, and more people provide all-round guarantees for the smooth operation of scientific research projects.

China Jinping Underground Laboratory Phase I (CJPL-I)

China Jinping Underground Laboratory Phase II (CJPL-II)

Image source: Tsinghua University Department of Engineering Physics official website

However, it is easy to get along with everyone. Here, people deal with each other without so many twists and turns, which makes Jing Mingkun feel relaxed.

Before, Jing Mingkun couldn't even screw in a screw. But when he arrived at the laboratory, he had to install and adjust many devices by himself. He quickly got the hang of it and learned to be independent. "Now, I can basically use all the tools you see in repair shops and processing workshops." Electric drills, wrenches, hammers, pliers, and screwdrivers for daily use are no problem for him.

China's Jinping Underground Laboratory has produced some cutting-edge research results, and the dark matter detection team is gradually narrowing down the possible hiding places of dark matter. "Sometimes I think that I have contributed a little to those amazing results. All the materials cannot enter without my detection. I think I am actually a relatively important part." Jing Mingkun said with a smile, "It is a bit exaggerated to say this, but you have to be sure of your existence."

After all, when faced with the grand task of exploring the frontiers of the universe, humans will inevitably feel insignificant.

Currently, China's Jinping Underground Laboratory is undergoing a second phase of expansion, and the available space will increase from the previous 4,000 cubic meters to 300,000 cubic meters. Researchers expect it to become a global deep earth science research center in the future, and different teams will gather here with their own puzzles to be solved.

"There will be more tasks and more complicated work in the future. I also need to improve myself to face more challenges." The Year of the Tiger is approaching, and Jing Mingkun has no special wishes. He just wants to be down-to-earth and do his job well.

During the Spring Festival, some staff will stay in this underground laboratory 2,400 meters deep, where they can listen to the footsteps of the Year of the Tiger and the sounds of all things in the universe.

Source: Science and Technology Daily

Editor: Zhang Qiqi

Review: Yue Liang

Final judge: Wang Yu