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Another anti-day project in China - Jinping Deep Underground Dark Matter Laboratory

Dec 26, 2018

In the laboratory, everyone should know more or less, then the underground science laboratory? I am afraid that there are not many people who know it. Let’s let Xiaobian take you to appreciate this 'great Chinese made'--Jinping Extremely deep underground dark matter laboratory.

Before we start talking about it, we should first know what is the reason for its existence.

That's because the well-known laboratory on the ground is not the ideal place for dark matter detection experiments, and the underground laboratory can do it because it is largely protected from cosmic rays in the depths of the ground. . Cosmic ray interference scientists have demonstrated the existence of dark matter, which is believed to constitute nearly a quarter of the mass of the universe.

Dark matter particles penetrate our bodies all the time, but the human body is ignorant. Even the most sophisticated instruments can capture the weak signals generated by its collision with the nucleus.

These signals are interspersed with a large number of background signals generated by cosmic rays colliding with the detector. It is like a beam of light, only in a house that is dark enough, with enough sophisticated instruments to push everything to the limit, it is possible to "see".

Prior to this, many countries such as the United States, Britain, France, Italy, Canada, Japan, India, and Russia have established good underground laboratories and achieved major scientific research results. Last year, the United States also established an underground laboratory with a depth of about 2,438 meters in Montenegro, South Dakota. In October 2010, Japan also built the XMASS underground laboratory at the underground of the Shengang Mine in Feifeng City, Ji County. An underground laboratory up to 350 meters deep in the UK was also launched in April 2010. The aim is to be the first country to discover dark matter in the world. There were no good underground laboratories in China before, especially in deep underground laboratories. Therefore, research topics in many fields cannot be carried out, or research work can only be carried out jointly with qualified laboratories abroad. Therefore, it is very necessary to establish a world-leading deep underground laboratory in China. It is of great significance for the independent research and application of scientific research to promote China's major fundamental frontier issues.

In May 2009, Tsinghua University signed a strategic cooperation agreement with Ertan Company. The agreement decided to use the Jinpingshan tunnel to cover the thickness of the world's largest geographical conditions, reducing the cosmic ray flux to one-tenth to one-hundredth of the ground level, providing a clean underground experimental environment for related precision experiments. The Jinping Deep Underground Dark Matter Laboratory was built using a tunnel of 18 kilometers of accessible vehicles built with the Ertan Hydropower Station in front of the Jinping Mountain in Sichuan. The top of the tunnel is a 2,500-meter-high mountain rock. It provides a superior environment for the construction of a very deep underground dark matter laboratory that needs to isolate cosmic rays that are extremely penetrating. In addition, compared with other underground laboratories that have been converted from mines, Jinping's extremely deep underground dark matter laboratory is more convenient for transportation. Researchers and scientific research equipment can enter by car without having to rely on elevators.

The first side of the underground laboratory was built on the side of the tunnel.

The Jinpingshan Tunnel Project, where the laboratory is located, has two traffic tunnels, four water diversion tunnels and one drainage tunnel. It is the largest hydraulic tunnel group in the world and needs to overcome many problems such as high ground stress and high pressure water inrush.

The two most difficult traffic tunnels in 2008 achieved double-hole penetration (17.5 km long). The tunnel with a depth of more than 1500 m occupied 73.1% of the total length of the tunnel and the maximum buried depth was nearly 2,400 meters. It is the first in China. The complexity of the engineering tunnel in the world's second deepest tunnel is self-evident.

The first phase of the Jinping Underground Laboratory utilized this traffic tunnel and excavated 40 meters long on its side, with a width of 6 meters and a height of 6 meters. The transportation here is more convenient, it can be reached by car, and it is built on the tunnel. It saves a lot of money, equipment and other inputs, and the initial investment of this laboratory is properly controlled.

Compared with the underground laboratories that have invested hundreds of millions of construction funds abroad, the Jinping underground laboratory can be said to have spent the 'minimum' of money, but has done the 'biggest' thing.

The second phase of the project currently under construction is intended to expand to 120,000 cubic meters on the basis of a 4000 cubic meter.

The second phase of the Jinping Underground Laboratory consists of 4 groups of 8 laboratories and their auxiliary facilities, which can accommodate more experimental projects in the deep science field. Moreover, this laboratory is open to the world. For researchers in Europe and the United States, this laboratory is a paradise for such research, and some American physicists even intend to stay there to work.

The completion and commissioning of the second phase of the project is of great significance. The construction of Jinping's deep underground dark matter laboratory marks that China has a world-class high-level clean low-radiation platform, and has the ability to independently carry out the use of international advanced basic research topics such as dark matter detection, and to promote China's major fundamental frontier issues. Research and applied research are of great significance.