To be honest, Xu Chuan is still hesitant about whether to attend this year's International Congress of Mathematicians.

In fact, whether it is from a personal point of view or from the perspective of academic development, he should participate.

The quadrennial International Congress of Mathematicians is not only about mathematicians from all over the world gathering to make new friends, but also about the wonderful mathematical presentations at the conference and the sparks of ideas with other top mathematicians.

There aren't many opportunities to talk to other mathematicians of the same top.

Especially for scholars like him who are at the forefront of the mathematical community, who want and are interested in further progress in mathematics, such an opportunity can be said to be not to be missed.

It's never the right thing for academics to do it on their own behind closed doors.

Even if he is used to doing research alone, it is based on the premise that he already has enough inspiration and ideas.

For those things that are unknown, it is difficult for one person to think about them to have a feasible path or direction enough.

Only when the sparks of thought communicate and collide with each other can brilliant wisdom shine.

To be honest, it had been a long time since he had such an exchange with other top math circles, so Xu Chuan still wanted to go.

However, considering the problems of national and security, it is a big problem.

I believe that if Mi Guo knew that he ran away from the country, he would definitely be happy to make some small moves.

After all, he has brought more than a little trouble to the United States.

After thinking for a while, Xu Chuan breathed a long sigh of relief, touched his mobile phone and made a call to Zheng Hai.

After a while, Zheng Hai pushed open the door and walked in.

"Professor, you're looking for me?"

Xu Chuan nodded and asked, "There's something I want to ask you." ”

Zheng Hai looked at him with a slightly puzzled look, and Xu Chuan continued: "If I am going to attend the International Mathematical Congress to be held in St. Petersburg, Tsarist Russia this year, will it be too difficult for you in terms of travel and security?" ”

He hasn't been abroad since he went to Sweden in 18 to receive a Nobel Prize.

And that time was actually easier to say, after all, in 18 years, all his achievements were basically in the field of theory, even if he won both the Fields Medal and the Nobel Prize that year, he was just a theoretical scholar.

Even if the rice country cares, it will not pay too much attention to it.

Now, the field he is involved in is not only theoretical, whether it is nuclear waste treatment technology, controlled nuclear fusion technology, or artificial SEI film in the field of lithium batteries, it is pure applied technology.

A scholar who can transform theoretical science into applied science is far more important than a purely theoretical scholar.

So if it's too troublesome and too difficult, it's okay not to go.

Hearing Xu Chuan's words, Zheng Hai was slightly stunned, Tsarist Russia, St. Petersburg? This seems to be the first time that this person has proposed to go abroad since he came back.

After thinking for a while, he said: "I'm not sure about this, after all, if you want to go abroad, there will be more things involved, and I will report to the above for communication." ”

After a slight pause, he looked at Xu Chuan and said, "But if you really want to go out, we will do our best to ensure your safety, and there must be a way." ”

For the person in front of him, he wants to go out to participate in a math exchange meeting, as long as he doesn't go to the United States, the above will definitely find a way to deal with this.

Trouble or something, put it on him is something that doesn't exist at all.

After all, the value he has created alone has surpassed countless people.

Nothing is more important to the state than to ensure his safety and academic environment.

What's more, the country I went to this time was still relatively safe Tsarist Russia.

Zheng Hai believes that the above will also agree to this matter.

Xu Chuan nodded and said, "Then this matter will trouble you, what is the result, remember to tell me." ”

Zheng Hai nodded, saluted, and then turned to leave.

Looking at the door that had been brought shut, Xu Chuan shook his head and refocused his attention on the information on his desk about the collider detector.

He remembers that in his previous life, after the LHC was upgraded to the high-brightness LH-LHC collider, the upgraded detection equipment was mainly the superconducting ring field detector (ATLAS) and the compact muon coil (CMS).

It was these two detectors that observed and discovered the complete collision information data of inert neutrinos.

So he put his main research goals and directions on these two.

The Superconducting Ring Field Detector (ATLAS) and the Compact Muon Coil (CMS) are two detectors that are universal detector devices on the LHC collider.

The former does not focus on a specific physical process, and is designed to detect as wide a range of signals as possible that may occur.

Therefore, no matter what kind of physical process the new physics takes or any new particles are generated, the superconducting ring field detector must be able to detect and measure its physical properties.

The latter, although also a general-purpose detector, has a completely different structure and detection range.

It is a device used to study the physics of proton collisions at 14 TeV centroid energy provided by the LHC accelerator.

The sub-detector contains a device used to measure the energy and momentum of photons, electrons, muons, and other particles produced after the collision.

As a physicist, Xu Chuan knows a little about these two detectors, but that's about it.

After all, he was just a physicist, not a physical engineer.

Now, what he has to do is to find out what the two detectors have in common to determine the upgrade direction of the subsequent high-brightness LHC collider.

This is the direction to win this competition.

Flipping through the information in his hand, Xu Chuan read the information in it with great interest.

For him, this is the first time he has consciously stepped into the field of theoretical engineering design, and many things in it are the first time he has seen them.

For example, the structure of the compact muon coil (CMS) detector, and the corresponding principle.

From this information, it can be seen that the CMS is composed of about 80,000 lead-tungsten crystals, which are characterized by high density and high light transmittance, similar to common lead glass.

When electrons or photons pass through crystals, they react with these crystalline materials, causing the so-called cluster emission phenomenon due to braking radiation and particle annihilation.

This released energy causes the electrons in the crystal to jump and emit light, which is then measured by a light detector attached to the surface of the crystal.

The measured values are then converted into electronic signals that can be used to estimate the energy of the original incident particles.

This ingenious thinking allowed Xu Chuan to understand for the first time how he and other theoretical physicists observed the particle data produced by the collision.

I have to say that this is a whole new world for him.

The whole process and related scientific and technological directions based on the combination of theory and application are a broader world than the purely theoretical field.

Over the next few days, Xu Chuan spent the next few days studying the LHC collider.

During these days, he saw and learned a lot of things that he had never known before, and he was very satisfied.

However, it is a pity that from the information in his hands, he did not find what he was looking for the most.

After reading a piece of information in his hand, Xu Chuan couldn't help but shake his head and sighed.

In these materials, there are a lot of detector construction materials with conventional assimilation properties, but how to explore the detection of higher-level and energy-level particle technology, there is not a single article on it, not even a direction.

But think about it, CERN's information on the flow of information from member states is basically screened, how can those technologies that are really in reserve be fully opened up to member states.

At this moment, another cute-looking assistant, Lu Ling, walked over.

"Professor, Academician Chang Jin from the National Space Science Center of the Academy of Sciences has arrived in the reception room." Lu Ling reported softly.

Hearing this, Xu Chuan raised his head and quickly said, "Invite him over, wait, I'll go over." ”

With that, he stood up and walked briskly towards the reception room.

In the reception room, Academician Chang Jin was sitting quietly on the sofa.

"Academician Chang." Pushing open the door, Xu Chuan walked forward quickly with a smile on his face to say hello to the academician Chang and shook his hand.

Academician Chang Jin is a researcher at the National Space Science Center of the Academy of Sciences, mainly engaged in the detection technology and methods of space gamma rays, high-energy charged particles, especially electrons, and scientific experiments.

He is also the designer of the Wukong Dark Matter Particle Detection Science Satellite.

Originally, Xu Chuan should have gone to him in person, instead of inviting him to run, but it just so happened that this academician Chang had recently returned to NTU, so there was no need to go to the capital.

By the way, by the way, it is worth mentioning that this academician Chang went out of NTU. At the beginning, he served as the director of the Purple Mountain Observatory, and later went to Beijing to serve as the director of the National Astronomical Observatory of the Academy of Sciences.

What's more coincidental is that the year he was elected as an academician was the same year as Xu Chuan.

"Academician Xu, long time no see." Chang Jin stood up with a smile on his face, stretched out his hand and shook Xu Chuan warmly.

The two exchanged pleasantries for a while, Xu Chuan cut to the point, and said: "It's really troublesome for you to make a trip, mainly because I don't understand some detector technologies, and I want to ask Academician Chang to help talk about it." ”

Chang Jin said with a smile: "Don't say that about trouble, as long as I can help." ”

After a slight pause, he restrained his expression and continued, "I don't know what problems you encountered this time, Academician Xu. ”

Xu Chuan thought for a while, organized his language and said, "That's it, about"

So, I want to learn about the technologies related to dark matter and dark energy detection on the Wukong Exploration Satellite."

After succinctly explaining the matter, Xu Chuan looked at the Changjin academician, not knowing if he could bring some help.

On the opposite side, on the sofa, after listening to Xu Chuan's question, Chang Jin thought seriously for a while before looking up.

"Regarding the detection technology used on the Wukong, it is mainly to indirectly find and study dark matter particles by detecting the direction, energy and charge size of high-energy particles in the universe."

"Its dark matter particle detection payload consists of four sub-detectors and payload number tubes, including the plastic flash array detector PSD, the silicon array detector STK, the BGO energy measuring device, and the neutron detector NUD."

"I can provide all these related technologies."

"Still."

After a pause, he continued: "However, the technology used on the Wukong exploration satellite is probably difficult, or theoretically impossible to apply to the Large Strong Particle Collider. ”

"Because they're not all the way thing."

Hearing this, Xu Chuan nodded slightly disappointed and said, "If that's the case, then there's really no way." ”

These days, he has been reading CERN-related materials and learning a lot about detection techniques.

In general, technologies for detecting dark matter can be divided into three main categories.

The first type is direct detection, that is, to detect the collision process of dark matter particles with ordinary matter when they pass through the earth, and this research is mainly carried out in the Jinping Mountain underground laboratory in Sichuan.

The second type is indirect detection, that is, looking for photons, positive and negative electron pairs, positive and negative protons, positive and negative neutrinos, etc., produced by the annihilation or decay of dark matter particles. This is the kind of research that Wukong is doing.

The last category is the collider and the accelerator detection.

In China, Chang Jin can be said to be the top expert in this field, even in the world, the Wukong satellite is also the space probe with the widest observation range and the best energy resolution.

He said that this road is basically impassable, and the development direction is completely different, so it is unlikely that the collider will apply this set of technology.

Chang Jin nodded and continued: "The principles, methods, and techniques used by accelerators and colliders to detect dark matter are completely different from indirect detection methods, including the fact that we are looking for target particles. ”

"So if you hope to use the technology used on the Wukong to modify the collider's probe, I'm afraid it will be very difficult to work."

Hearing this, Xu Chuan thought for a moment, and then asked, "Then in terms of detection technology, does Academician Chang have any suggestions or directions?" ”

He is only a physicist and is not involved in the detection of various particles and scientific experiments.

If he were to find the corresponding particles from a series of detected data, he would have countless ways.

But to design and build a technology and equipment to detect particles is not his field of study.

Of course, what he is studying now is not actually detection technology, but the lowest scientific principles.

Only by finding the core principle can it be possible to build your own detector.

Chang Jin thought for a while and said, "For the indirect detection of dark matter particles, the most ideal research object is antimatter cosmic rays. ”

"Because theoretically, dark matter annihilation or decay usually produces equal amounts of positive and antiparticles. In space, the explosion of stars, pulsars, and supernovas will give birth to a large number of these particles. ”

"So it's the best fit."

"As for the Large Strong Particle Collider, a few years ago, I went to CERN to communicate, and at the meeting, someone proposed that the detector should search for the energy and momentum loss signals produced by dark matter during the annihilation and decay."

"Maybe the direction of the probe can try this."

"However, whether it is the Wukong satellite or the means of the collider, these are indirect evidence for the detection of dark matter and dark energy."

"If you want to directly observe dark matter, maybe Academician Xu can go to Jinping Mountain."

"The high-purity germanium detector over there may be applied to the collider?"

PS: It's over the holiday, o(╥_╥)o, I worked all day before I went home, asking for a monthly pass! It's the last day of double, and the bigwigs have a monthly ticket in their hands to vote.

PS: Push this book, a new book from the great gods!

"Brother, I want to recruit An Da Song"

[Welcome to the mythical version of Water Margin Auto Chess!] 】

The mythical version of the Great Song! Gaowu version of the Water Margin!

The military generals pull out the mountains, the sword hangs in the nine heavens, and the sword is cold for 30,000 miles.

The strategists are wise and close to the demons, calling for wind and thunderstorms, and summoning the earth to bind the spirits.

Gu Jing, who has lived for thousands of years in his dream: "Brother, I want it. Zhao'an, this great Song! Slaughter that monstrous alien race! ”

But......

"Dude has to fool a person into getting on the thief ship first, and it's best to be a master!"

"Good! It's up to you! ”