Into Unscientific

"Neutron bomb?"

Hearing the word that came out of Xu Yun's mouth.

Several bigwigs at the scene were startled for a moment, with obvious surprises on their faces.

They would never have imagined that Xu Yun would link the tandem accelerator with the neutron bomb.

Qian Bingqiong even stood up from his seat with a bang, and the chair was overturned on the ground due to the excessive movement.

But he didn't have the slightest thought of lifting the chair up, but while swallowing his saliva, he looked at Xu Yun steadily:

"Xiao Han, what are you talking about? That string of accelerators can help us produce a neutron bomb?"

Hearing this, Xu Yun took a deep breath, looked at Qian Bingqiong solemnly, and gave an affirmative answer:

"That's right."

Seeing this, Qian Bingqiong's face suddenly turned red, and he suddenly felt a heat flow from his heart to his mind, so that his body shook twice.

Fortunately, Lu Guangda on the side had sharp eyesight and quick hands, and quickly supported Qian Bingqiong's arm, so there was no accident that endangered his life.

A full half a minute passed.

Qian Bingqiong's face finally returned to calm, and he slowly sat back on the stool that was upright by Lao Guo.

This moment.

The atmosphere of the whole scene is really a little delicate.

The room looks like an extremely cold icehouse, but under the silence that seems to freeze the air, there seems to be something surging.

neutron.

This is a microcosmic particle that was discovered very early. It is uncharged and neutral, so it is called a neutron.

Neutrons are ubiquitous, and all atoms have neutrons except hydrogen's isotope No. 1, "protium".

You eat a mouthful of rice, which contains more than 10^24 neutrons.

At first glance, neutrons may seem like nothing special.

But if the neutron breaks away from the atom to form an extremely penetrating beam of neutrons, its properties change—a real killer.

Students who have been human in this life should know it.

Cells are the basic units that make up organisms—note that they are the basic unit, not the smallest unit.

Any cell in the human body contains countless molecules, and molecules are composed of atoms, that is to say, there is a group of huge number of atoms in each cell.

As for atoms, they are composed of protons, electrons, and neutrons.

A neutron beam passes through the human body.

It will cause the molecules and atoms in the human body to deteriorate or become charged ions, causing nuclear reactions in the carbon, hydrogen, and nitrogen atoms in the human body, and destroying cell tissues.

On the macroscopic level, people will suffer from convulsions, intermittent coma and muscle disorders, and lose the ability to resist. In severe cases, they will die within a few hours.

The earliest record of a neutron beam killing can be traced back to August 21, 1945.

At that time, Daglien, a scientist at the Alamos National Laboratory, was accidentally exposed to severe neutron radiation while doing experiments.

Although he underwent immediate special medical treatment, the neutron's destructive effects were irreversible—at least at the time.

Ever since.

The hapless scientist died 25 days later at the age of 24.

Here comes something more interesting.

When Daglien was alive, he had a senior who was one year older than him, and the two had a good relationship. This person was called Sam Cohen.

The epitaph on Daglien's tombstone was carved by Sam Cohen himself.

to be honest.

No one knows if Daglien's death had any real effect on Sam Cohen, but the fact is.

In the 1950s, Sam Cohen first proposed the conjecture of neutron beams as weapons, and made many theoretical designs.

neutron bomb.

The concept of this weapon has since stepped onto the stage, and later generations also recognized Sam Cohen as the father of the neutron bomb.

The nuclear explosion power of a neutron bomb is very small, only one-tenth of that of an ordinary nuclear bomb, but it can release a large number of neutron beams.

These neutron beams would penetrate armored structures, killing people in large numbers without causing damage to property.

for example.

A neutron bomb with the equivalent of 1,000 tons of TNT exploded at a height of 90 meters above your head.

Shock waves, optical radiation and radioactive contamination, these 'dirty things', only work within 180 meters from the epicentre.

However, the neutron flow 800 meters away from the explosion center can penetrate the 30 cm thick steel plate, causing casualties to those protected by the steel plate.

that's right

Killing does not hurt anything, and it does not have serious radiation effects.

For example, there is a well-known joke on the Internet in later generations, which comes from the mouth of an old man in the Yellow River:

If you go to Wudaokou Vocational and Technical College to explode a neutron bomb, you can leave a whole body at Peking University next door, and the Chinese Academy of Sciences next door will be able to receive it in two days.

But on the other hand.

The neutron bomb is clean and clean, but in the current period of time, this thing is definitely a fantasy weapon.

Don't talk about rabbits, Gaul, Britain, these countries.

Even the two super hooligans Mao Xiong and Duan Hai are still in the conception stage of the neutron bomb at this time.

Up to now.

Today, the world's most advanced neutron bomb results still come from across the sea:

They will produce a neutron warhead the size of a TV next year. After the turret discovered that this thing was purely cheating funds, the project team was sent to Greenland to collect ice.

Follow the historical trajectory.

It was not until 1977 that the first neutron bomb in human history was actually developed and tested on the other side of the sea. Since then, it has entered the development track of third-generation nuclear weapons.

The Rabbits will not be able to get this thing in 1984, and then it will be officially announced in 1999.

And now that Xu Yun said that he could produce a neutron bomb, how can he keep Qian Bingqiong and others from losing their composure?

after awhile.

Qian Bingqiong couldn't help shaking his nose twice, and asked Xu Yun again:

"Xiao Han, are you sure this accelerator is useful for the development of neutron bombs?"

Xu Yun still nodded heavily, and explained:

"I'm sure, Director Qian, neutron bomb neutron bomb, as the name implies, involves the nature of neutrons, which is the so-called neutron radiation."

"The generation method of high-energy neutrons can rely on the reactor, but the property detection has only two means."

"One is to intercept high-energy rays from outer space, and the other is to bombard a heavy metal target with a high-speed electron beam, causing the target to release a large number of neutrons, and then collect their scattered data."

"So if you want to develop a neutron bomb, either you have the ability to fly into outer space to intercept high-energy rays, or you can only rely on particle accelerators to assist in research."

"Of course, the deuterium-tritium neutron source can be regarded as one of the standard solutions, but if this thing can be developed, we will have mastered the development of hydrogen bombs and neutron bombs."

Hearing Xu Yun's words.

Qian Bingqiong was silent for a moment, subconsciously glanced at Lu Guangda at the side.

Qian Bingqiong's original idea was to ask Lu Guangda for his opinion, but Lu Guangda didn't notice his gaze, but fell into deep thought.

after awhile.

Lu Guangda couldn't help tapping on the table a few times with his fingers, and said after deliberation:

"Xiao Han, using a particle beam to bombard a heavy metal target to generate neutrons is indeed a feasible technology."

"But the question is, can the energy level of .80MeV really allow us to have a lot of neutron data?"

"I remember Mr. Zhao and the others calculated a model back then. I can't remember the specific data, but the energy level needs to be at least above GeV."

"Although the tandem accelerator at the University of Cambridge is the best in the world, it is still more than ten times worse than GeV."

"If the time comes and we can't get the data back, we will lose our wife and lose our army."

Lu Guangda's thinking was very clear. He didn't think about the value of the neutron bomb, but directly thought about the theoretical feasibility.

Everyone present knew very well that neutron bombs are not a bit more important than atomic bombs in this era.

First, it is a reflection of the level of national defense technology.

Being able to produce a neutron bomb before Mao Xiong and Duanhai would be of incalculable help to the rabbits in the international arena—this year is different from later generations, and today’s rabbits really need international recognition.

Second is

Neutron bombs do not pose much radiation risk and are generally much cleaner than atomic bombs.

If the rabbits can handle the miniaturization of the neutron bomb, its deterrent effect will be completely different.

After all, rabbits these days are standard barefoot and not afraid to wear shoes. When something happens, even if you are across the sea, you will fight as soon as you say it - the peninsula war has just passed and there is not yet a round.

Indeed.

For various reasons, rabbits must not dare to use atomic bombs.

But if it is a miniaturized neutron bomb, then hey.

So after learning about Xu Yun's thoughts.

Lu Guangda immediately shifted his thinking from "whether it's worth it" to "whether it's possible".

As for Mr. Zhao in his mouth, he was naturally referring to Mr. Zhao Zhongyao.

As the current head of the domestic accelerator industry, Zhao Zhongyao has deduced the impact energy levels required by many particles.

Four years ago, he pushed to the excitation energy level where neutrons can be observed and recorded in large numbers, which is about 1.1-1.3GeV, which is more than ten times that of 80MeV.

However, in the face of Lu Guangda's doubts, Xu Yun shook his head and gave him an answer that surprised him:

"Director Lu, with all due respect, there are actually some mistakes in the value calculated by Mr. Zhao."

Lu Guangda was startled for a moment:

"mistake?"

Xu Yun nodded, with a hint of emotion on his face:

"That's right, experimental-level neutron beams actually don't need such a high-energy level--Director, do you have a pen here?"

Li Jue, who was on the side, was listening intently, but he didn't react for a few seconds, but immediately nodded:

"Yes, yes, I'll get it for you now."

Say it.

Li Jue got up and walked to the desk, took a pen and a piece of paper, and handed them to Xu Yun:

"Give."

Xu Yun took the pen and paper, spread out the arithmetic paper on the table, and wrote to Lu Guangda:

"Director Lu, according to Goodsmit's classification back then, neutrons have a spin of 1/2. You should know this, right?"

Lu Guangda hummed lightly, but the expression on his face didn't change much.

The concept of spin was proposed in 1925, and now even in China there are a lot of relevant materials, many physics undergraduates are familiar with it, let alone a big guy like him.

Then Xu Yun went on to write:

"A beam of electrons with momentum ki=2π/λ and energy E=2ki2/2mn is incident on the target, and the scattering process satisfies the conservation of momentum and energy."

"Then there is the transferred momentum Q=kfki, that is |Q|=ki2+kf22kikfcos(2θs), and ω=EiEf."

"Where θs is the angle between the initial momentum and the final momentum, and ω is the frequency at which neutrons are excited out of the target."

"The scattering cross section satisfies Fermi's golden rule, that is, d2σ/dΩdEf|λi→λf=(kf/ki)(mn/2π2)2||2δ."

"Then use the Born approximation to treat the incident wave as a plane wave, then substitute the delta function to get the wave vector of the neutron, right?"

Lu Guangda thought for a long time this time, went through Xu Yun's thoughts carefully, and nodded after confirming that there was no problem.

Lao Guo, Fifth Master Qian and others on the side also showed expressions of approval.

Li Jue quickly scanned the scene and found that everyone except himself responded, so he put his hands around his chest and nodded his head a few times in a thoughtful manner.

Then Xu Yun handed the pen to Lu Guangda, and said to him:

"Director Lu, please calculate the wave vector parameter of neutrons—assume that the energy level of neutron scattering is 20 MeV."

Lu Guangda glanced at him, didn't say much, took the pen and paper and calculated.

Although he does not have a specific map of neutron scattering, given the known particle spin and the magnitude given by Xu Yun, it is enough to do a derivation of the dynamic structure factor.

But do the math.

Lu Guangda raised his brows suddenly, and looked at Xu Yun with astonishment:

"17.87? Xiao Han, how is this possible?"

well known.

There are many parameters to describe the movement of a particle, such as frequency, wave number, wavelength and even equivalent temperature.

Another example.

wave vector.

The neutron wave vector scattered at 20 MeV is about 2.20 to the power of 1. This parameter was calculated by Lu Guangda himself when he was studying for a Ph.D. across the sea.

Not to mention that in today's 596 project, due to various calculation needs, a large number of related wave vector parameters are also involved.

It is not an exaggeration to say.

Lu Guangda could forget anything, but he could never forget this value.

But the value of the neutron wave vector obtained according to the conventional reasoning is completely eight times different from what he knew, which obviously challenges the three views.

It's like asking you how long an adult cat is including its tail. Some people may say one meter, and some may say 40 centimeters, but who would say that their cat is five meters long?

So it's obvious.

There must be something wrong somewhere.

Think here.

Lu Guangda looked at Xu Yun again, turned the paper to him, and asked him:

"Xiao Han, what's going on?"

Seeing this, Xu Yun didn't hold back, but sighed slightly, and explained:

"Director Lu, to tell you the truth, this is an anomaly discovered by a senior from Cambridge University called Yifang Tongtong in the experiment.

"He is a fan of vector calculations, so he rarely wanted to use wave vectors to describe neutrons, but after the calculations, such a strange situation happened."

"So he made repeated comparisons in mathematics, and finally found a situation, that is."

"This is the neutron's magnetic moment at work, and its anomalous magnetic moment caused its error in the model."

Lu Guangda was stunned for two seconds, but soon his voice became louder:

"Magnetic moment?"

Xu Yun nodded heavily.

In a sense.

The error caused by the calculation of particle magnetic moment has pitted the physics community for a whole generation.

magnetic moment.

When this word is mentioned, many people may subconsciously think of the magnetic moment of a magnet.

But in fact.

In addition to the macroscopic magnetic moment, there is another concept of microscopic magnetic moment in the invisible microscopic particles.

It is an intrinsic property of particles and is related to spin.

At the beginning, the meaning of spin was explained, that is, the rotation of nucleons about their central axis in a complex common motion state.

A spinning particle induces a moment of momentum around it that aligns with its axis of rotation -- for example, a top that keeps it upright as it spins is its moment of momentum, and a spinning charge likewise creates a moment of momentum around itself called a magnetic moment. magnetic field.

And in all particles.

Neutrons, an uncharged particle, also have a magnetic moment, an anomaly discovered by Stern (not the NBA one) in the 1930s.

In this period.

The neutron magnetic moment calculated by the physics world is about -3.82 unit nuclear magnetons, but the physics world knows nothing about it.

How the magnetic moment came about and what it means for neutrons is still unknown.

According to Xu Yun

It is precisely because of the existence of this magnetic moment that there is a problem in the mathematical calculation?

Then Xu Yun paused and continued to explain:

"Director Lu, you should remember Stern's model for calculating the neutron magnetic moment?"

Lu Guangda nodded, picked up a pen and wrote down an expression on the paper:

μns=gnse/2mphbar/2=gns/2ehbar/2mp.

Xu Yun reached out and clicked on the mp, and said:

"Look here, the mp here is the isospin mass of the free neutron, that is, the two orthogonal basis vectors of the isospin doublet state, and together they form a subspace with an isospin of 1/2." (Note: To avoid being interpreted in a predictive manner, this is actually a weak isospin that is easy to understand in terms of calculations)

"From the point of view of quantum mechanics, symmetry will lead to degeneracy of energy levels - take the hydrogen atom as an example, when the perturbation theory is not considered, when n and l are the same, regardless of the value of m and Sz, The energy is all the same."

"This is the degeneracy of energy levels caused by typical symmetries, and these degenerate energy levels form an invariant subspace"

"So when the neutron is inside the target, that is, in the unexcited state, the spin magnetic moment radius of the negative charge in the outer layer needs to deduct an electric potential barrier."

"That is, the specific initial state λi of the neutron should actually undergo a Lorentz transformation. At the same time, the neutron does not excite the movement of the atomic nucleus, so corresponding to elastic scattering, the energy of the neutron is conserved."

Listening to Xu Yun whispering like a succubus, like a demon.

Lu Guangda couldn't help picking up the pen again, and quickly calculated on the paper.

as expected.

After deducting an electric potential barrier as Xu Yun said, the value he calculated this time is already close to 2.20^-1.

The reason why it is close rather than equal is mainly because he chose an average parameter of the experiment in memory for the convenience of calculation, and the data cannot be too fine-after all, this calculation was a bit sudden.

Immediately afterwards.

Lu Guangda realized something again, and substituted this idea into Zhao Zhongyao's model.

ten minutes later.

Lu Guangda wrote down a number with some regret:

69.7MeV.

This moment.

Among the big shots at the scene, even Li Jue could easily understand the meaning of this number:

It represents the energy level at which neutrons can be knocked out in the laboratory and leave enough information behind.

It was twenty times faster than the original figure, and it was well within the coverage of the tandem electrostatic accelerator at the University of Cambridge.

See this situation.

Qian Bingqiong couldn't help opening his mouth again, wanting to ask Lu Guangda's opinion:

"land"

However, before he could say a word, Lu Guangda interrupted him again:

"Wait! Xiaohan, according to your way of thinking, isn't that what you mean?"

"Because the outer negative charge is also spinning and shares its spin engine with the light proton, the spin of both positive and negative charges will generate a magnetic moment, but since the equivalent radius of the outer negative charge is larger than that of the inner positive charge, so The total magnetic moment of the neutron will appear as a negative charge magnetic moment?"

"That is, within the existing particles, are there other smaller particle models?"

When it comes to this.

The expression on Lu Guangda's face had already taken on a hint of horror.

Looking at Lu Guangda who was a little belated.

The corner of Xu Yun's mouth finally couldn't help raising a slight arc:

"If there is no accident, it should be so."

That's right!

Except for the neutron bomb.

Xu Yun also had another reason to get the tandem electrostatic accelerator no matter what.

That is.

He wants to make Huaxia's theoretical physics circle open, and from then on, rabbits can use it on the application and theoretical ends

Walk on two feet together!