Chapter 647 Yu Min's Configuration Is Released! (Part 1)

“.”

At this moment.

Looking at Yu Min, who looked curious, Xu Yun was slightly stunned.

After a while.

His little heart seemed to be tugged by someone, and a stream of heat instantly rushed from his neck to behind his ears, and his breathing stopped for a moment.

Oh my god? !

What the hell did I hear?

It was mentioned earlier.

A little keyboard warrior said that as long as there is enough nuclear material, an atomic bomb can actually be made through a large number of trials and errors.

Although the cost of this trial and error will be very high, the logic itself is not wrong-that is, it can be piled up with resources

But hydrogen bombs are different.

Any experiment before the configuration of hydrogen bombs is futile, and the theoretical breakthrough of the configuration is very dependent on the inspiration of a few genius scientists.

The most typical representatives are the two big guys, Taylor and Ulam, who are also recognized as the fathers of hydrogen bombs across the sea.

In the 1950s.

Just when all nuclear physicists were at a loss for the configuration of hydrogen bombs, Taylor and Ulam jointly published a paper, in which they believed that the X-rays produced by nuclear explosions might be the key to detonating hydrogen bombs.

Because in order to meet the conditions for fusion, in addition to the extremely high temperature produced by nuclear explosions, high-density fusion materials are also required.

Because normally, the shock wave of a nuclear explosion will blow all nearby materials to pieces, and it is impossible to form the environment required for fusion.

Tai-U believes.

If X-rays can be released before the shock wave after a nuclear explosion. Although the time difference is as small as nanoseconds, these few nanoseconds are enough to trigger fusion of the energy of X-rays through a cleverly designed configuration before the hydrogen bomb material is blown apart.

This is the famous T-U configuration principle, and it is also the last paper published by these two fathers of hydrogen bombs.

Since then, they have never published any theories or data on hydrogen bombs, and the configuration of hydrogen bombs has been classified as top secret by the other side of the sea, even in 2023.

But on the other hand.

Although the specific configuration of hydrogen bombs is highly confidential, the relevant theoretical principles of hydrogen bombs can still be traced.

For example, the base reaction of hydrogen bombs is inseparable from three types of thermonuclear reactions, namely deuterium-deuterium fusion, deuterium-tritium fusion and tritium-tritium fusion.

This is like when you make boiled cabbage, you definitely need materials or equipment such as chicken and cabbage boilers. It is the most basic problem and cannot be kept secret.

But the problem is that knowing these three types is not very meaningful at all. Only when a specific answer is determined is it valuable.

Because both deuterium and tritium are extremely precious materials, and it is too difficult to prepare them at this time.

Deuterium needs to be extracted from seawater, which is very expensive, and the preparation of tritium can only rely on nuclear reactors. The technical difficulty is high and the output rate is low. In a sense, its value far exceeds the same amount of gold.

The method used by the other side of the sea is to build a factory to purify deuterium from seawater, then use the extracted deuterium to artificially transmute in the reactor to produce tritium, and then make tritium targets and tritium beam accelerators for target shooting experiments to measure the reaction cross section of light nuclear reactions.

This is the most natural step, but for the poor rabbits and almost zero industrial base, the country cannot even guarantee the most basic power supply at present, so how can such a system be built?

Although a nuclear reactor was built in China last year, its actual task is actually to serve as a backup for atomic bombs - if uranium bombs cannot be made, then this reactor will provide plutonium to develop plutonium bombs.

So in the original history, this nuclear reactor will not be officially put into operation until seven years later.

As for the temporary transfer to tritium. Maybe it can be done in eight or ten years, but by then the opportunity will be cold.

Therefore, the rabbits are destined to be unable to replicate the system across the sea. Their only way is to first determine which is more important, deuterium or tritium, and then choose a direction without thinking.

It's like when you buy a graphics card, 4070ti, 4080, 4090 are all good, the best way is to buy them all and try them one by one.

But the problem is that you don't have that much budget now, so you can only read various reviews first to determine which card has the best cost-effectiveness before buying it.

Originally, according to the agreement between Xu Yun and the capital writer, he would tell Dayu about this when the time is right.

Unexpectedly, before he opened his mouth, Dayu had already realized this?

Then Xu Yun took a deep breath, looked at Dayu pretending to be puzzled, and asked him:

"Dayu, you also saw that I just woke up not long ago, so I couldn't keep up with what you just said. Can you explain the situation in detail?"

Dayu nodded when he heard it, took the initiative to walk to the window and opened the curtains (Yang Kaiqu had already gone to inject paclitaxel on a daily basis), and then returned to Xu Yun.

He dragged a small stool and sat down, explaining to Xu Yun:

"Comrade Xu Yun, you should know that the so-called nuclear reaction cross section is a very important concept in nuclear reactions - it can even be ranked among the top few."

Xu Yun nodded lightly.

Nuclear reaction cross section is actually a very interesting word.

It does not describe a certain unit area, but the probability of a pair of particles colliding.

But not only is it called cross section, the basic unit is also square meters, square centimeters, etc.

Actually, this is not surprising.

You can first recall the concept of cross section in the macroscopic world:

If the radius of a sphere is r, then its cross section is πr.

When the trajectory of another sphere intersects with this cross section, the two will collide.

Then expand this situation to the microscopic field:

Suppose there are two atomic nuclei, deuterium nuclei and tritium nuclei. Imagine that the tritium nucleus is surrounded by a force field, which is usually considered to be a strong nuclear force field and an electromagnetic force field.

So the shaded area perpendicular to the direction of motion of the incident particle is the reaction cross section. Particles entering this area will enter the range of action of the strong nuclear force or the electromagnetic force.

When considering the strong nuclear force, this force area is called the fusion cross section.

The basic unit of the fusion cross section is called barn or bar. One bar is equal to 0.8x10^-28 square meters, but 0.8 is generally regarded as 1 and then written as 10^-24 square centimeters.

Then Dayu skillfully wrote down a few numbers in his notebook and said:

"Comrade Xu Yun, in the nuclear fission process, the fission cross section of neutrons and U235 is 600 bar - this is a parameter that has been determined by many parties."

"But the nuclear fission cross section does not need to consider constraints. If the scenario is converted into a calculation of the fusion cross section, the electromagnetic repulsion needs to be taken into account - that is, the two target nuclei must have a certain initial velocity."

"The T-U configuration was constructed across the sea, in which tritium accounts for a large proportion."

"But. After I introduced the Bright-Wigner equation calculation, the entire fusion cross section changed mathematically."

I saw Dayu first draw an image of [L] rotating 90 degrees clockwise on the paper, and his tone became less certain. Come:

"The original image of the cross section is like this, like an L flipped 90 degrees, in Chinese, it is first raised, then horizontal to the right."

Then Da Yu drew another curve:

"But after the introduction of the Breit-Wigner equation, the fusion cross section becomes a curve when it is calculated to the eighth decimal place."

"That is, even at very low temperatures, or even if the two particles have very low kinetic energy, fusion reactions can occur, but the cross section is very small."

"And the upper limit of this cross section is 5 bar, which is too different from the conclusion that the maximum cross section of the tritium-tritium reaction is 15 bar calculated by the other side."

"At the same time, the secondary shape of this cross section is spherical, so."

Looking at Da Yu who was hesitating, Xu Yun suddenly had a flash of enlightenment in his mind.

So that's it

He felt that Dayu's state yesterday was a little strange. It turned out that he thought of the fusion cross section when he was calculating:

At that time, he was responsible for calculating the cylindrical secondary of the atomic bomb. Although this thing is not the same concept as the secondary of the hydrogen bomb, the shapes of the two are the same.

But Dayu calculated that the secondary was a sphere. In this case, Dayu naturally slacked off.

But even so, Dayu still completed the calculation work on time. It's really terrifying.

According to the original historical development.

Dayu would think of this problem at the earliest in two and a half years. Now, is this directly accelerating the growth period of Kunkun?

But since the thing has happened, Xu Yun has no reason to hesitate.

So he quickly straightened his body and said to Dayu:

"Dayu, so what you are struggling with now is that you are not confident in your results. Or do you not know what physical concept to use to explain this mathematical result?"

Dayu nodded quickly.

He hesitated about this matter.

Mathematics often does not lie, but sometimes the correctness of mathematics does not mean that reality is correct.

For example, the Alcubierre metric of later generations is the analytical solution of the curvature engine.

This thing is perfect in mathematics and impeccable, but have you ever seen a curvature engine appear in reality? ——The space-time distortion caused by the Photoshop does not count.

There is also Witten's M theory, which is also a typical example of perfect mathematics but not confirmed by physics.

Da Yu's temperament is extremely rigorous, not to mention that the development of the hydrogen bomb is related to the fate of the country, so if he doesn't figure out this problem, it will not be a matter of not being able to sleep for several days.

Then Xu Yun made a calm gesture to Da Yu and explained:

"Comrade Da Yu, if you want to discuss the specific design of the hydrogen bomb with me, to be honest, I may be powerless."

"But this fusion cross section involves particle physics scenarios, so to be honest, I really know a little bit."

"In fact, the reason for this situation is very simple, that is, the other side of the sea did not take into account the quantum effect of subatomic particles."

Da Yu was stunned:

"Quantum effect?"

"That's right."

Xu Yun nodded vigorously and said:

"To be precise, it is the tunneling of microscopic particles. effect, wave effect, and resonance effect. "

"Dayu, you just said that you introduced the Breit-Wigner equation, which is the Breit-Wigner equation, right?"

"Then you must have also derived the nuclear fusion variant of this equation, that is, the resonance cross section of single-level neutron capture, right?"

Dayu immediately responded that it was right, and turned the notebook forward a page, revealing a formula on it:

σγ（Ec）=σ0ΓγΓ(E0Ec)121/(1+y2)+2Γ(EcE0).

Seeing this, Xu Yun secretly said that it was indeed so.

The formula of greater than is actually not difficult to understand. E0 is the energy of the resonance peak in the center-of-mass coordinate system, which is the energy that matches Ec+ΔEb with the excited state of the composite nucleus. Γ is the total energy width corresponding to the 12 resonance peak, and σ0 is the largest cross section, Γγ is the radiation capture width.

This is considered one of the basic variations of the Breit-Wigner equation, but some of its deeper physical meanings have not yet been analyzed.

Then Xu Yun thought for a while, went through his thoughts in his mind, and said to Yu Da:

"Greater than, based on this formula, you first introduce quantum tunneling, and then think about what will happen?"

"Quantum Tunneling"

Hearing this, Da Yu touched his chin twice and quickly began to think.

Quantum tunneling.

It refers to the phenomenon that particles cannot pass through energy barriers under classical mechanics, but have a certain probability of passing through them under quantum mechanics.

The basic principle is based on the wave-particle duality of quantum mechanics. A particle can behave in the form of a wave, and its wave function can attenuate outside the barrier, but there is a certain probability of penetrating the barrier and entering the inside of the barrier.

Inside the barrier, both the amplitude and phase of the wave function are affected, while outside the barrier, the amplitude of the wave function decays exponentially with distance, but its phase does not change.

When a particle encounters an energy barrier, its wave function will be reflected and transmitted inside the barrier according to the properties of the wave function.

Even when the energy is lower than the height of the barrier, there is a certain probability that the particle will pass through the barrier and emerge on the other side.

This phenomenon is very common at the microscopic scale. For example, electrons passing through the energy band gap of materials, alpha rays passing through objects, etc. are all quantum tunneling phenomena. Related concepts were also proposed decades ago.

A few minutes later.

Yu Yu, who was deep in thought, suddenly thought of something, and his eyes suddenly lit up:

"Comrade Xu Yun, is this what you mean?"

"Due to the existence of quantum tunneling, the temperature required to overcome the Coulomb barrier is smaller than expected, and the probability of particles overcoming the electrostatic barrier increases, coupled with the approximation of the Maxwell distribution at the temperature under the medium."

"So the kinetic energy of the particles colliding with fusion is in a narrow energy window, resulting in a further reduction in the fusion cross section?"

Xu Yun nodded heavily:

"That's right."

Quantum tunneling actually has a great impact on nuclear fusion. For example, the reason why the sun can naturally undergo fusion reactions is also due to the existence of quantum tunneling.

The window larger than mentioned is actually the famous Gamow window, but for further analysis, Lawson's criterion and three products must be added, so I won't go into details.

But at the moment, the core of Da Tangle's problem mainly lies in the physical properties of the cross-section difference, so Xu Yun only needs to help him clarify the context.

as expected.

After being enlightened by Xu Yun on the influence of quantum tunneling.

Da Yu quickly focused on the resonance effect.

This time Xu Yun didn’t need any prompting, he quickly started his own analysis:

"If we consider the resonance effect in nuclear fusion, then it obviously refers to the 3α reaction."

"After inelastic scattering occurs, the remaining atomic nuclei are still in the excited state, and the energy of the released neutrons must be significantly smaller than the energy of the incident neutrons, that is, the load and the energy of two or more neutrons that may be released."

"Composite nuclei may release the energy of two or more neutrons. Neutrons and atomic nuclei can interact without neutron absorption and the formation of composite nuclei. This should be explained by the resonance energy zone. Hi, I How could I not think of that? I’m so stupid.”

"Then do this. Then do that."

More than ten minutes later.

Yu Da put the ballpoint pen on the table with some emotion, and a glimmer of light flashed in his eyes:

"Sure enough, the cross-sections of all light nuclear reactions are absolutely impossible to exceed 5 bars. Taylor and the others made a mistake in calculating this data!"

Before the TU duo jointly released the god-like work, in 1950, Taylor had published a paper alone.

The paper deduces the cross-section problem of light nuclear reactions in detail, and declares with great certainty that the maximum cross-section of the tritium-tritium reaction is 15 bar.

The derivation process of this conclusion is very delicate, and it cannot be deliberately released to induce outsiders. At that time, several major European and American countries were fully studying the theoretical issues of light nuclear reactions.

And according to what Mao Xiong has learned, the T-U configuration does indeed extend this theoretical result.

That is to say, all hydrogen bomb data designs across the sea are based on "the maximum tritium-tritium reaction cross-section is 15 bars."

This approach cannot be said to be problematic, because the 15 bar scenario is obviously greater than the 5 bar scenario.

It's like you have a computer and the actual total power is 550W, but you made a mistake when calculating and calculated it as 1000W.

So you bought a 1000W power supply. There is definitely no problem with this wattage supporting 550W - the wattage of the power supply is not afraid of being too high, just too low.

But on the other hand.

The cost of a 1000W power supply is obviously much higher than that of a 550W power supply, so the expenditure is much higher out of thin air.

If you are a rich guy who can easily vlog people for 50, this expense is nothing.

But if you are a poor person who has to shop around to buy an egg, then the money is quite considerable.

The current rabbits fall into the standard latter category, so the correction of this error is extremely exciting news for both China and the country.

Looking at Dayu, who clenched his fists, Xu Yun couldn't help but smile and continued:

"So Dayu, your idea is correct. In the structural design of the hydrogen bomb, it is indeed possible to ignore the tritium-tritium reaction and use other reactions instead."

"So."

Xu Yun originally wanted to say [Just continue to calculate according to this idea], but before he finished the second half of his sentence, Dayu suddenly interrupted him:

"Comrade Xu Yun, wait a moment!"

Then, without waiting for Xu Yun to speak, Dayu suddenly looked at him:

"Comrade Xu Yun, if we consider quantum tunneling as you said, can we use it in material compression?"

"For example, give up certain convergence angles and form a special gradient penetration shock wave?"

Xu Yun:

"Huh?"

Note:

The schedule is down, 15 surgery