Into Unscientific

  Chapter 601 Eligibility to walk on two feet

   "Neutron bomb?"

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

  Several bigwigs at the scene were stunned 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 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. Instead, he swallowed his saliva while looking at Xu Yun:

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

  Xu Yun took a deep breath when he heard the words, looked at Qian Bingqiong solemnly, and gave an affirmative answer:

   "Exactly."

  Qian Bingqiong's face turned red suddenly when he saw this, and he 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.

   After a full half a minute.

  Qian Bingqiong's face finally regained his composure, and he slowly sat back on the stool that was upright by Lao Guo.

   Right now.

  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.

   Neutrons.

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

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

  You eat a bite 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 are different—a real killer.

  Students who are human in this life should know it.

  Cell is the basic unit that constitutes an organism—note that it is 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.

   When the 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 the carbon, hydrogen, and nitrogen atoms in the human body to undergo nuclear reactions and destroying cell tissues.

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

  The earliest homicide record of neutron beam 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 was immediately given special medical attention, the neutron's destructive effects were irreversible—at least at the time.

  So ever since.

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

   Here comes something more interesting.

  Dalglien had a senior who was one year older than him when he was alive. The two had a good relationship. This person was called Sam Cohen.

  The epitaph on Daghlian's tombstone was engraved by Sam Cohen himself.

to be honest.

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

  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.

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

  These neutron beams would penetrate armored structures, killing a large number of people without causing property damage.

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 explosion center.

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

   is also

   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 the old man of the Yellow River:

  If you blast a neutron bomb at Wudaokou Vocational and Technical College, 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 most advanced neutron bomb results in the world 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, and it has since entered the third-generation nuclear weapon research and development track.

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

  Now that Xu Yun says he can produce a neutron bomb, how can Qian Bingqiong and others not lose 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 neutron bomb research and development?"

  Xu Yun still nodded heavily, and explained:

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

   "The method of generating high-energy neutrons can rely on the reactor, but there are only two methods for attribute detection."

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

   "So if you want to develop a neutron bomb, you must either 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 is also one of the standard solutions, but if this thing can be made, we will have mastered the development of hydrogen bombs and neutron bombs."

   Hearing Xu Yun's words.

  Qian Bingqiong was silent for a moment, and subconsciously glanced at Lu Guangda beside him.

  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 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 master a large amount of neutron data?"

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

   "Although the tandem accelerator at Cambridge University is considered the world's number one, it is still more than ten times behind the GeV level."

   "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 consider whether the neutron bomb was worth it or not, but directly considered the theoretical feasibility.

  Everyone present knew very well that neutron bombs are not a little 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 Duan Hai was invaluable to the international help of the rabbits—these days are different from those of later generations, and today’s rabbits really need international recognition.

  Secondly, it is

  Neutral bombs do not have much radiation risk, and are generally much cleaner than atomic bombs.

  If the bunnies 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 hehe.

  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 general manager 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 attentively. 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 be clear about 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, and many physics undergraduates are familiar with it, let alone a boss like him.

   Then Xu Yun wrote:

  "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 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 the 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.

  Old Guo, Qian Wushi 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 neutron wave vector parameter—assume that the energy level of neutron scattering is 20MeV."

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

  Although he does not have a specific spectrum 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 counting.

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

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

   Well known.

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

   Another example.

   Wave vector.

   The neutron wavevector 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 due to various calculation needs in today's 596 project, a large number of related wave vector parameters are also involved.

   It is not an exaggeration to say.

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

  But the value of the neutron wave vector obtained according to conventional reasoning is completely eight times different from what he knew. This is obviously a challenge to 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 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?"

  Xu Yun didn't hold back when he saw this, 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 Tongxing in the experiment.

   "He is a fan of vector calculations, so he rarely wants 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 abnormal 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 the magnetic moment of particles has pitted a whole generation in the physics community.

   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, which 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 magnetic field around itself called a magnetic moment. .

   And in all particles.

  Neutrons, an uncharged particle, also have a magnetic moment, which was 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 appeared 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 perspective of quantum mechanics, symmetry will lead to degeneracy of energy levels—taking hydrogen atom as an example, when n and l are the same, regardless of the value of m and Sz, when the perturbation theory is not considered, the energy all the same."

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

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

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

   Immediately after.

  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.

   Right now.

  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.

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

  See this scenario.

  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! Xiao Han, according to your thinking, isn't that saying"

"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.

  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 has another reason to get the tandem electrostatic accelerator no matter what.

That is.

  He wants to make Huaxia's theoretical physics world open, and from then on, rabbits can

  Two feet walk together!

  (end of this chapter)