From all-round academic master to chief scientist - Chapter 250 Control interference and diffraction!

The wavelength of X-rays is similar to the distance between atomic planes inside the crystal. The crystal can be used as a spatial diffraction grating for X-rays. That is, when a beam of X-rays irradiates an object, it is scattered by the atoms in the object, and each atom generates a scattered wave. , these waves interfere with each other, resulting in diffraction.

The angle at which the rotating crystal faces the X-ray irradiation will change when the X-ray penetrates the inside of the crystal, amplifying and shrinking.

Based on this principle, Lin Xiao can design a crystal structure so that its interior can achieve the effect of diffracting X-rays neatly, and when moving the crystal, it can amplify and reduce X-rays.

In the past, this would have been an extremely troublesome matter, requiring a lot of testing, a very high amount of calculations, and even a supercomputer, for which the cost would also be very high.

But now, because of his wave coherence superposition equations, this problem has been infinitely simplified, and there is no need to conduct a lot of tests. You only need to write a program, and then follow the diffraction of X-rays inside the crystal. Effect, and then use the computer to perform calculations according to this program, he can easily get a complete result.

Of course, before that, he had to at least determine whether his wave coherence superposition equations were really useful by calculating the internal diffraction of several other crystals.

Although after his complete calculation results, he can be sure that his calculation is correct, but who can know whether the actual situation is correct?

And this matter is not troublesome.

After leaving the house, he went directly to the institute and came to the physics laboratory.

By the way, he called on the intern researchers who had conducted experiments with him before.

In fact, the team led by Lin Xiao can be regarded as a research group and has funding, and these intern researchers are paid.

As for the source of funding, it naturally comes from the research institute.

Lin Xiao’s research institute has received strong support from the state, and in his opinion, the funds allocated are almost inexhaustible.

Just say that when the institute was first built, the state allocated him 2 billion in funding and told him to see if there were any missing instruments and equipment. Then he could buy them if he wanted to. If there was not enough, he could just apply again.

Because of this, Dingguang Research Institute has also attracted the attention of many researchers. Although the second recruitment has not yet begun, many people have expressed their desire to join.

However, these matters require Lin Xiao’s approval, and he has no such plan for the time being.

Let’s wait until he completes his current work before discussing these issues.

“The X-ray diffractometer has been debugged, and now it is time to scan the crystal No. 1!”

“Scanning begins!”

In the physics laboratory, several intern researchers controlled the X-ray diffractometer in front of them.

In the diffractometer, a simply polished crystal has been placed. As the X-ray diffractometer is started, the test begins.

As the X-rays were irradiated, an image gradually appeared on the computer screen next to it. What the image showed was the result of diffraction of the X-rays inside the crystal.

As time passed slowly, these intern researchers began to watch from the side.

X-rays can hurt people. For example, CT rooms in hospitals can cause certain physical harm to staff.

However, the diffractometer will not hurt people. Even if X-ray lithography machines are built in the future, there is no need to worry about hurting workers.

Because the X-rays in the CT room are originally used to irradiate people, staff will inevitably be injured by those radiations while working.

The X-rays in the diffractometer are used to illuminate objects, so protective measures can be taken. Only a 1 mm lead plate is needed to reduce the radiation to a level lower than that of a mobile phone.

So there is no need to worry about the harm caused by X-ray lithography machines to people. In fact, even extreme ultraviolet light, although called ultraviolet light, can actually be called soft X-rays. It itself is also harmful to the human body, but as long as it is added For protection, you don’t have to worry about it at all.

So these researchers are not worried about being exposed to radiation while sitting next to them.

They looked at Lin Xiao over there and were very curious about what he was going to do, so they all asked: “Professor Lin, what are we doing now? Are we going to start designing crystal structures?”

Lin Xiao, who was sitting on another computer, smiled and said, “Yes.”

The intern researchers were immediately surprised: “Professor Lin, have you already clarified the laws and causes of diffraction?”

“That’s more or less the case.” Lin Xiao replied, “So our job now is to verify my results.”

The intern researchers were even more surprised.

Professor Lin said that he found the laws and causes of diffraction. Can they say “impossible, this is absolutely impossible”?

They are not so stubborn yet.

Of course, they also want to know what the law and reasons are. Has Lin Xiao published the paper?

However, Lin Xiao did not reveal it to them for the time being. Since he knew that this thing might be related to their domestic military development, he would first produce the paper and then send it to relevant departments, such as those specializing in military technology. Research the organization and ask them to see if confidentiality is necessary.

Of course, after his theory is published, there is no need to worry about whether it will be stolen. It has been registered. If he really dares to steal it, even if the person who steals it has a strong background, he can still have Lin Xiao’s current situation. Is your background awesome?

Just think about who the senior party officials in their research institute are. There is no one on top of the senior party officials in Dingguang Research Institute, only the people.

Time passed quickly, and the X-diffraction scan took a long time, so they all kept waiting. Lin Xiao had been inputting a program before, and now, he finally completed the program.

This program is a program that simulates crystal X-ray diffraction based on the principle of Lin’s wave coherent superposition equation.

As long as you input the wavelength, intensity, and incident angle range of the X-ray, as well as the crystal structure and crystal refractive index, you can get the diffraction image of the X-ray when it penetrates the crystal.

Then, he entered various data of the crystal being detected in the X-ray diffractometer, and then pressed the Enter key.

Then, an XRD pattern appeared in front of him.

The XRD pattern refers to the X-ray diffraction pattern, which is mainly wavy lines with abruptly rising peaks.

Through the analysis and calculation of these wavy lines, the crystal structure, texture and stress can be clarified.

At this moment, the intern researchers over there suddenly shouted: “It’s done! Professor Lin!”

“The analysis results are out!”

It turns out that the X-ray diffractometer scan was completed.

“Professor Lin, I want to send you the picture… huh? Professor Lin, when did you get the image?”

When an intern researcher turned around to ask Lin Xiao, he suddenly discovered that an XRD pattern had appeared on his computer screen. Isn’t it very similar to the analysis result in front of them?

Or should I say, exactly the same.

However, he was always the one connected to the computer of the X-ray diffractometer. As soon as the results came out, he had not sent them to Lin Xiao. Why did Lin Xiao have them?

Lin Xiao smiled: “This is an image calculated by my simulation.”

Everyone present was stunned: “Simulation calculation?”

“Yes.”

Lin Xiao nodded, smiled and spread his hands: “Didn’t I just tell you that I have found the laws and causes of interference and diffraction, so according to my results, as long as we know the internal structure of the crystal in advance, we can know its XRD pattern.”

The people present were stunned for a moment and had not yet reacted.

Once you know the crystal structure, can you then know its XRD pattern?

“Professor Lin, if we want to know the crystal structure, don’t we have to analyze its XRD pattern first? If we all know the crystal structure, why should we care about its XRD pattern?”

Lin Xiao smiled and said: “Everyone, don’t forget our purpose. We are to build a crystal that can amplify and reduce X-rays!”

These researchers reacted immediately.

yes!

The purpose of their research was not to analyze the crystal structure. The crystal structure they used was known before.

The purpose of their experiment was to help Lin Xiao verify his results!

so……

This result…

“Professor Lin, the verification was successful?”

Their eyes all lit up and they looked at Lin Xiao excitedly.

“Yes, it was successful.” Lin Xiao smiled slightly, “Of course, only the first crystal was successful. We still need to continue to verify more crystals. In addition, we must confirm the error between my calculation results and your actual scanning results. “

“good!”

The researchers immediately took action again.

There is a certain error between the actual XRD pattern of the first crystal and the XRD pattern calculated by Lin Xiao’s simulation.

However, Lin Xiao believed that this error came from the error of their X-ray diffractometer itself.

And his calculation results are more accurate.

Calculation results are more accurate than experimental results, and it is not non-existent. For example, when the industry studies turbulence problems, it often uses DNS and direct numerical simulation to solve NS equations. There are even a large number of examples that show that this kind of calculation The credibility of the results exceeds that of experiments. Of course, since the well-posedness of the solution to the NS equation has not yet been proven, errors will still occur.

Next, they went through several experiments to verify it, and without exception, they all proved that Lin Xiao’s conclusion was correct, and although there were errors, these errors were all caused by the precision of the instrument itself.

All in all, Lin Xiao can officially announce——

He controls interference and diffraction!