Spy film comes true: “Miaochi Imaging” through architecture and the structure of the earth – Guo Jiaming, professor of physics at Central University, and Chen Jianji-pensi, professor of earth sciences

Spy film comes true: "Miaochi Imaging" through architecture and the structure of the earth - Guo Jiaming, professor of physics at Central University, and Chen Jianji-pensi, professor of earth sciences

Imagine the classic part of a spy movie: the protagonist successfully sneaks into the enemy base, then picks up his mysterious device and installs it on the wall. Within seconds, all space configuration drawings inside the site were displayed on the screen. Ann. This kind of technology, seen through the entire building, makes the film show the color of science fiction of the future. So, in the real world, how long do we have to develop technology like this?

“There is no need for the future, in fact it is possible now, but it is not possible to take as few seconds as possible,” said Guo Jiaming, a professor in the Department of Physics at Central University. Professor Chen Jianxi of the Department of Geography, Professor Lin Yucheng of the Department of Electrical Engineering, and Professor Lin Jixon of the Academy of Physics at the Academy of Sciences are implementing a project to study this technology, but the main object of their perspective is not buildings, but mountains.

A new imaging technique for taking X-rays of large objects

Before explaining Mune Imaging, we must first introduce what “Mune” is. Muyon is one of the basic building blocks of matter. It was first used by physicist Carl Carl in 1936. Carl Anderson discovered that like electrons, they belong to leptons. The biggest difference between the two is that the mass of muons is 210 times heavier than that of electrons, which gives muons a stronger penetrating ability. Muons in nature are mainly caused by cosmic rays coming from space that attack gaseous molecules in the atmosphere, and then come to the surface through the decay of pi mesons. As you read this article, innumerable muons fly in all directions, traveling close to the speed of light in your body.

Mions form from the decay of pi mesons after cosmic rays hit atmospheric gaseous molecules. Photo / by Professor Guo Jiaming and Professor Chen Jianxi

Another characteristic of muons is that, in dense matter, its energy is rapidly lost. In the restoration project of the Fukushima Daiichi nuclear power plant, Mune detection technology was used to detect highly concentrated radioactive materials such as uranium and plutonium from a safe distance to prevent repair workers from being exposed to radiation, which is not possible with other imaging technologies. For low-density buildings, or for earth structures such as mountains and rock formations, muons can penetrate several kilometers. The basic principle of muon imaging is to analyze the number of muons detected at different angles and then reverse the density of each part of the detected target. As long as there are two points of data, a three-dimensional perspective system can be established just like X-rays for buildings and mountains. In the library of Suo University, it can take a week or more to get good results, even if you can’t film it in a few seconds like a movie.

Author Guo Jiaming said that mune imaging is a term not often heard in Taiwan, but experiments on it appeared in the 1950s. The most famous of these was in the 1960s. The research team used mions without harming the pyramid structure. Hidden room inside. Author Guo Jiaming learned about this technology in 2014 at a high energy physics seminar in Spain.

“I do high energy physics. People often think our research results are of no use value. At the time, hearing such a report could do some good to people’s livelihoods and economics. It’s so wonderful.” Author Guo Jiaming I think high energy physics is the study of elementary particles, which is very pure physics, but this field also makes a lot of contributions to human life. Carl. Anderson won the Nobel Prize for his discovery of positron in the same year as the discovery of muon. At the time, no one knew how to use it, but now positron is used to treat cancer. This is a new technology developed from scratch. Energy physics, and Mune imaging is one of them. One.

A few years after the conference in Spain, Mr. Guo Jiaming had a teaching assistant who found a piece of paper in a new type of muon detector and helped two students try to create it themselves. Two years ago, the Ministry of Science and Technology introduced the Shackleton Project to promote cross-field research. After some adjustments, Mr. Guo Jiaming, his former neighbor, Mr. Chen discovered Jianji and began implementing a project that attempted to use Muyon imaging technology to study the Earth’s field. Science.

Muon detector.Photo / Presented by Prof. Guo Jianming and Prof. Chen Jianshi

“Our geophysical researchers are always using different methods to measure the surface area of ​​the Earth’s field field. Different detection techniques need to be actively developed,” said author Chen Jianxi. Miaochi’s body size density is a traditional measurement of gravity, but this method has not. Objects are often in units of several kilometers, and there is no way to make a detailed diagnosis. “In Taiwan, we are prone to landslides due to heavy rains, but such causes do not occur for any reason. Dangerous slopes are broken in some places and the density is smaller than dense and complete rock formations. It is difficult to obtain tens of thousands of meters of material with this type of traditional gravity method, but can be solved by Muen detection technique. Space is very small, so it can be used in this type of space to detect sloping-hazardous land. ”As a new technology in development, Muon Imaging can detect large objects with resolutions up to tens of thousands of meters. It does not require additional synthetic signals such as seismic waves and currents. Mr. It has various benefits that Sen Jianxi expects, but of course, there are many challenges to face.

The first utility test exploring the way forward for tunnel engineering

Miaochi Imaging Application Project by Guo Jiaming and Sen Jianxi. The research team consists of members from various disciplines such as the Department of Physics, the Department of Earth Sciences and the Department of Electrical Engineering. It has been implemented till the second year. During the first year and a half, the team focused on two goals: the development of new inventors and the development of reverse mechanisms.

Mutton Imaging Application Project Research Team led by two authors Guo Jiaming and Sen. Jianxi. Photo / by Prof. Guo Jiaming and Prof. Sen Jianxi

According to author Guo Jiaming, in the field of high-energy physics, writing programs and designing circuit boards for experiments is common. The detector they are currently developing is different from the traditional detector used for muon imaging. It is small in size and requires a reduced voltage from 1000 volts to 30 volts. It is highly mobile for outdoor testing. Once the measured data is obtained, a reverse algorithm is required to review the density of each part of the observation object. The technology of this area is constantly being improved by members of the Department of Earth Sciences. Author Sen Jianxi said that the reverse algorithm was first and foremost an important technology in the field of geophysics. This is similar to splitting the observation object into smaller squares and predicting the density of each square based on the number of muons measured at different positions and angles. The author joked on the page of Guo Xiaoming that most people often have the impression that physicists are immersed in calculations. After this collaboration, he did not know that the field of geography required a lot more understanding of mathematics than the field of physics.

After a thorough test, the team will begin field detection tests by the end of 2020. At that time, the anti-Ambing Shield tunnel of the Shimen Reservoir was being dug and Mr. Sen Jianxi was inspecting the body at the site and he introduced the team to the construction site to find it. “The drilling process of this tunnel may face a part. Geographically, we call this the Jindian fault. The Jindian fault is located above the amber. There is a very large layer of coal. The excavation process will often collect biogas. There is a function in tunnel engineering called forward exploration,” Mr. Sen said. Jianxi said the tunnel will be drilled forward so that the material of the rock mass in front will continue to be detected.The traditional detection method uses mechanical waves, but Mr Sen Jianxi believes it is possible to change the traditional method of mune imaging and secure future Flint Road projects. Constantly measured.

A detector is set up in front of the tunnel under excavation at Ambing to measure the number of mions passing by. Photo / by Professor Guo Jiaming and Professor Chen Jianxi

Since the muons in the vertical direction pass only through the atmosphere, the number of measured muons is very large when the detector is aligned directly above. As the elevator angle of the finder decreases, the more obstacles the muons pass through, the less and less muons the measurement will take, and the less it will pass in the horizontal direction. Ambing’s terrain is flatter than expected. Although detection is not possible, the number of inventors should be increased, otherwise the number of test days should be extended to obtain sufficient data.

Apart from extending the test time, the test itself went very smoothly and the three-month test has not been interrupted so far. High energy physics tests are usually carried out indoors, and temperature and humidity are strictly controlled. Author Guo Jiaming was initially concerned about external tests, he encountered problems such as insufficient power settings, but the team quickly solved them one by one with a new type of detector. It successfully survived drastic changes in temperature and humidity, and the temperature difference between day and night continued to fluctuate between 20 and 30 degrees, and the afternoon thunderstorm sunny day actually reached practical application standards, providing enough data to complete the reverse algorithm.

After Ambing’s field test, the research and development phase of the entire research can be completed and officially enter the mass production phase. Currently, the area of ​​the detector built by the panel is 20cmx20cm. In the future, it plans to increase the number and create bigger inventors. By the end of the Shackleton project, it is expected to be four to six times larger than the current one. The target is the current hundred. The double size allows groups to measure mountains and change locations faster, and increases the ability to scan mountains. In a few years, the technology of X-ray mountains and buildings will no longer be science fiction, and the rock layers and mineral veins that are hidden deep beneath the surface will be easily provided to us by muon imaging.


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