Chapter 450 A new era of nuclear physics! Particle accelerator! "Father of Nuclear Physics" Bruce!
When chemists read the paper on nuclear fusion and shouted that the alchemist is resurrected and artificial elements are about to be realized.
Even the title "Lord of the Elements" has spread.
But these chemists are very bitter in their hearts.
Because the nuclear reaction equation of nuclear fusion is not a chemical reaction.
Chemical reaction refers to the process in which atoms rearrange and combine to form new substances.
During this process, the atoms of the elements themselves do not undergo any changes.
For example, hydrogen and oxygen react to form water.
The hydrogen atom in the water molecule and the hydrogen atom in the hydrogen gas molecule are the same hydrogen atom, and there is no change before and after the reaction.
The fusion of hydrogen nuclei into helium is different.
In this process, the hydrogen atoms disappeared forever and were all transformed into helium atoms.
So, this is a physical nuclear reaction process, not a chemical reaction.
In this era, the instruments required to study atomic structure are the most advanced and top-notch.
And you also need to make a lot of homemade equipment.
Even most physicists cannot figure out the equipment required for nuclear fusion.
Not to mention chemists.
How can the bottle experiment be compared with the difficulty of the nuclear physics experiment?
As a result, chemists were immediately confused.
The method of turning stone into gold is very good, but it's a pity that they don't know how to use it.
So, the work of artificial elements can only be done by physicists.
In real history, the first artificial element [technetium] was created by American physicist Lawrence.
Then he sent the new element to two chemists in Italy for identification.
“Hey, it was just created.”
“Go and test whether it is element 43.”
Chemists are so humble in front of physicists. .
Because Lawrence invented a field of nuclear physics, an awesome and heaven-defying instrument.
Cyclotron!
The biggest function of this instrument, which he first proposed and developed, is to accelerate particles.
It can accelerate microscopic particles to close to the speed of light!
According to the mass-energy equation, the particles at this time have huge energy, and the collision of two particles is enough to cause a nuclear fusion reaction.
Therefore, Lawrence was the first in the world to create artificial elements.
He also won the 1939 Nobel Prize in Physics.
Lawrence, who is only 19 years old this year, is still an undergraduate student majoring in physics at the University of South Dakota.
A few years later, he would meet his most important alumnus, Oppenheimer, at the University of California, Berkeley.
Now Oppenheimer is only 16 years old and still a talented American high school student.
During Li Qiwei's trip to the United States, neither of them had the opportunity to listen to the speech.
But in the near future, they will be able to see Professor Bruce's unique talent.
In short, chemists love and hate nuclear fusion.
What I love is that the periodic table of elements will undergo earth-shaking changes.
The sad thing is that all these changes were brought about by physicists.
As a result, all chemists in the world envied at the same time:
“Physicists are really the darlings of natural science!”
UK, Cavendish Laboratory.
Among the physicists, the person who had the strongest reaction to the nuclear fusion paper was undoubtedly Rutherford.
Because the paper on nuclear fusion was so important to Cavendish.
At this moment, he is sharing this paper that shocked the academic world at a large group meeting.
In addition to Rutherford's students and assistants, Fowler and Dirac also came over.
Fowler will soon become Rutherford's son-in-law, so naturally he often goes to the laboratory.
And Dirac took the initiative to request to come to the laboratory.
Although he is currently preparing for the second Physics Olympiad, he still has free time.
He cherished the opportunity to come to Cambridge, his dream university.
What's more, Rutherford is a super boss in the world of physics.
Being able to participate in the other party's group meeting, even if you just sit in on it, is enough to benefit a lot.
So he sat with Fowler in the corner of the room.
Rutherford had just finished reading the content of the paper when he suddenly said:
"Hey, I suddenly feel a little pity."
This made the students below look at each other.
What do you regret so much?
Rutherford smiled and said:
“In fact, I almost proposed the concept of nuclear fusion first.”
Wow!
Everyone was shocked!
They didn’t expect such a thing.
Is Professor Rutherford also studying nuclear fusion?
Looking at everyone’s surprised expressions, Rutherford continued:
"In my experiment where I discovered protons, the phenomenon of nuclear fusion has actually occurred."
"N nuclei first combine with alpha particles. This process is actually the process of nuclear fusion."
"It's just a pity that I am an experimental physicist. The focus is on the phenomenon of the experiment itself."
"On the contrary, it neglects to think about its essence."
"Theoretical physicists like Professor Bruce like and are good at theory. A high level of thinking. ”
“This is the biggest difference between theoretical physicists and experimental physicists.”
“However, I have serious doubts now.”
“Professor Bruce’s concept of nuclear fusion is derived from our Wendi Xu learned from his master."
"So next, I will organize you to visit the Quantum Research Institute."
"Try to get Professor Bruce to return some interest."
After everyone heard this, they all laughed.
I am afraid that only Professor Rutherford is qualified to make such a joke.
They did not doubt Professor Rutherford's words. The other party was indeed just one step away from proposing nuclear fusion.
But even such a small gap requires a flash of inspiration.
There are many such situations in the history of science.
After the joke, Rutherford then asked:
“Do you have any opinions or questions about this paper?”
“Don’t be afraid, put it forward boldly.”
"As the authority in atomic research, we Cavendish must always be at the forefront!"
At this time, Chadwick asked:
"Professor, I have a question."
"Since in your previous experiment, N nuclei have already fused with alpha particles."
"This shows that nuclear fusion is not necessarily Extremely high temperatures and pressures are required.”
“The rays produced by radioactive substances are enough to bombard atomic nuclei and produce fusion.”
“Then why does the nuclear fusion proposed by Professor Bruce require such harsh conditions?”
Everyone was stunned when they heard this.
This angle is very novel, but very interesting.
“Yes, doesn’t this mean that nuclear fusion at room temperature can be achieved?”
“Oh God! That’s incredible!”
Hearing this, Rutherford said, He looked at Chadwick approvingly.
However, everyone's ideas are doomed to fail.
He explained:
“This is the difference between macroscopic and microscopic.”
“You should know that the number of basic units contained in one mole of substance is 6.02 ×10. ""In other words, although its mass is only 28g, the volume of one mole of nitrogen is approximately 22L."
"But it contains 6.02×10 nitrogen molecules."
"This is an unimaginable astronomical number."
"So many nitrogen molecules together, even if they are only slightly heated ”
“There may be one or two molecules that collide due to the increase in kinetic energy, resulting in a nuclear fusion reaction.”
“But because there is not enough temperature and pressure, this reaction is only accidental and cannot continue. .”
"And it is impossible to allow other molecules to polymerize together."
"Even the fused nuclei may soon separate again."
"Nuclear fusion at the level of one or two molecules The reaction has no meaning."
"It's like chemists recently claimed that it turns stone into gold."
"What's the point of just generating a gold atom?"< br>
"The nuclear fusion of macroscopic matter is the real nuclear fusion."
"Not to mention objects as massive as stars."
"If you want nuclear fusion to continue, then It must require extremely high temperature and pressure."
Rutherford's explanation made everyone suddenly realize.
No wonder Professor Bruce first applied the concept of nuclear fusion to stars.
It turns out there is still such a consideration.
At this time, Rutherford continued:
"And the most important point."
"That is, the way I bombard the nucleus with rays is impossible. Controlled. ”
“We cannot quantitatively determine the nuclear fusion reaction in a certain nucleus.”
"If you want to truly study the mysteries of atomic nuclei, you must need controllable nuclear reactions."
"Even if you only control one atomic nucleus."
"In this case, you need Atomic nuclei have very high energy and can Ensure that a nuclear reaction will definitely occur."
"Rather than relying on a negligible probability to allow the nucleus to react spontaneously."
"Unfortunately, there is currently no such instrument or technology. ”
At this time, Dirac in the corner frowned slightly, then relaxed.
He said directly:
"Professor, why not invent an instrument that can accelerate microscopic particles?"
"According to the mass-energy equation, as long as the speed of the particle If it is large enough, its mass will also become larger."
"When two such particles collide, their kinetic energy may be converted into energy enough to initiate nuclear fusion."
Wow!
Everyone looked back.
Everyone knows this young man named Dirac.
It is said that Professor Rutherford brought him back to Cambridge specifically for the surprise training for the Physics Olympiad.
When I saw it today, it certainly lived up to its reputation!
This idea is very clever!
After hearing this, Rutherford was also stunned.
Soon, a smile appeared on his face.
"Dirac, your proposal is very good."
"It shows that you have great physical intuition."
"I believe that as more and more people study nuclear fusion, someone will definitely create such an instrument."
Dirac's face was neither sad nor happy.
He knew that with Professor Rutherford's strength, he might have already thought of it, but he just didn't say it out loud.
Rutherford: Yes, that’s it!
After all, this method of accelerating particles is not an innovation at all.
By adding an electric field to charged particles, they can be accelerated directly without any difficulty.
The important thing is how to accelerate to close to the speed of light.
After all, the kinetic energy of particles in a low-speed state is completely insufficient for nuclear fusion.
This is what Dirac just calculated on the manuscript paper.
In fact, in the mid-to-late 1920s, with the concept of nuclear fusion being proposed.
Physicists have already begun to discuss the principles of accelerating charged particles.
Because only by allowing particles to obtain higher energy can physicists create "controllable" nuclear reactions.
Thus studying various properties of microscopic particles.
By the early 1930s, there were concepts and prototypes of electrostatic, linear and other types of accelerators.
Finally, the cyclotron was born and instantly became the main instrument for studying nuclear physics.
Next, everyone discussed various issues about nuclear fusion.
Finally, Rutherford said excitedly:
“In 1896, Professor Becquerel discovered that elements are radioactive, which can be regarded as the beginning of nuclear physics.”
< br>“Since then, the Curies, myself, and other physicists have conducted in-depth research on radioactivity.”
“However, these studies have not gone deep into the field of atomic nuclei.”
"It wasn't until Professor Bruce discovered the atomic nucleus and proposed the planetary model that nuclear physics entered a new stage."
"The next step was the discovery of the proton and the proposition of the proton-neutron model."
"Until the concept of nuclear fusion was proposed, we first Recognize the interaction between atomic nuclei."
"From now on, bombarding atomic nuclei with rays will become the main method of studying nuclear reactions."
"And nuclear reactions will also become the main method of nuclear research in the future. ”
"Professor Bruce's paper, to some extent, brings nuclear physics into a new era!"
Boom!
Everyone is shocked!
For a physics master like Rutherford, his perspective on the concept of nuclear fusion is very different from others.
He does not think about synthesizing new elements like a chemist does.
Because that means nothing to physics.
Does the new element created not conform to the laws of quantum theory?
It’s just an addition to the periodic table of elements.
Similarly, he will not marvel at the terrifying power of the artificial sun like astronomers do.
Because this is more of an engineering problem than a physics problem.
No matter what, it is impossible for humans to create a celestial body that is exactly the same as the sun in the sky.
And the energy, structure and evolution of stars, in the final analysis, are all within the larger framework of physics.
These, like atomic science, are just a specific research direction.
However, this does not mean that nuclear fusion is not important to physics.
On the contrary, it is very important and crucial.
Because it made physicists realize that protons and neutrons are far from being two independent microscopic particles that can be explained.
In the paper on nuclear fusion, what is the process of protons and neutrons being fused together.
What is the interaction between them like?
These are what physicists are most concerned about.
It is also the most essential question.
The basis of stellar nuclear fusion and artificial elements is the atomic nucleus model.
Rutherford guessed well. Nuclear fusion already involves the force in the nucleus.
That is strong and weak force.
Nuclear fusion is related to the strong force, while nuclear fission is related to both the strong and weak forces.
These contents will soon shock the physics community again at the third Bruce Conference!
After hearing Rutherford's summary, Chadwick felt excited.
"Professor Bruce can be called the father of nuclear physics!"
(End of this chapter)