Reborn and become a Great Scientist

Chapter 248 196 Make America Great Again

The idea of ​​bombarding deuterium nuclei with protons, that is, hydrogen nuclei, was entirely out of Rutherford's wishful thinking and unrealistic thinking after learning the news that Chen Muwu separated hydrogen isotopes from liquid hydrogen.

Leaving aside the difficulty of preparing deuterium gas, since Chen Muwu discovered deuterium, the British Air Company has undertaken the production of deuterium gas from various universities with a small amount of use. Although they use the same distillation method as Chen Muwu, the purity is not high. high.

Using deuterium as a target is purely laborious and thankless. First of all, under normal temperature and pressure, deuterium is a gas, which is difficult to control.

Secondly, there are one proton and one neutron in the deuterium nucleus, and the number of neutrons accounts for 50.00%.

However, there are two protons and two neutrons in the helium nucleus, and the proportion of neutrons is still 50.00%.

Of course, helium has the same problem as deuterium, that is, it is also a gas.

But when it comes to the lithium atom, it has three protons and four neutrons, and the neutrons account for more than half.

If it is really possible to use protons to bombard neutrons from the nucleus, then this kind of atom with a higher probability of bombarding neutrons should also be selected as the target.

What's more, Chen Muwu also knew that no matter how protons were used to bombard deuterium, helium, or lithium nuclei, the neutrons in the nuclei would never be knocked out.

But bombarding lithium nuclei with protons is indeed a feasible experiment.

Chen Muwu had the most say in the matter of crossing the river by feeling other people's stones.

The one he wants to touch this time is none other than Cockcroft who is by his side now, assisting him in designing and manufacturing the proton source.

In the original history, after Cockcroft successfully developed a particle accelerator in the Cavendish Laboratory, the first experiment he did was to bombard a target made of lithium metal with high-energy protons accelerated by the accelerator .

There are two advantages of using lithium metal as a target:
The first is that it is a solid. Although its chemical properties are very active, it is much easier to control than invisible hydrogen (deuterium) and helium.

Second, because lithium atoms have a small atomic number and a small radius, there are not many nucleons in the nucleus, which is commonly known as a light nucleus.

In this way, the accelerated high-energy protons can easily enter the interior of the nucleus and undergo a nuclear transmutation reaction with the nucleus.

For the proton and the lithium nucleus, the specific nuclear reaction between the two is that the proton enters the interior of the lithium nucleus, changing the nuclear charge of the nucleus from three to four.

Lithium-7 with three protons and four neutrons also becomes beryllium-8 with four protons and four neutrons.

On the periodic table of elements, the relative atomic mass of beryllium is 9, which means that most of the stable beryllium elements that appear on the earth appear in the form of beryllium-9 with four protons and five neutrons.

For beryllium, beryllium-8 is just an unstable isotope. After being bombarded, it will soon split due to instability and evenly split into two identical helium nuclei.

In other words, the lithium element at the target position will emit two alpha particles after being bombarded by high-energy protons.

In addition to the nuclear transmutation of atomic nuclei using artificially accelerated particles for the first time, this nuclear reaction can also prove the correctness of Einstein's mass-energy equation experimentally for the first time.

Whether it is the mass of the proton and lithium atom before the reaction, or the mass of the two alpha particles after the reaction, measuring the mass of these particles is no problem at all for the development of modern science, and it is easy to obtain the specific mass in the laboratory. numerical.

As long as two simple addition calculations and one equally simple subtraction calculation are performed, it can be easily concluded that the mass sum of the particles before and after the reaction is inconsistent, that is, the so-called mass loss occurs.

According to Einstein's mass-energy equation, E=mc, it is easy to calculate how much energy is converted into this part of mass loss.

And this part of energy, of course, will not disappear out of thin air.

As long as you measure the binding energy released during the whole process of the nuclear reaction just now, and compare the experimental data with the theoretical calculation, you can know whether Einstein's theory is right or wrong.

In the original historical process, Einstein proposed this formula as early as the miracle year of 1905.

But it was not finally confirmed by Cockcroft in his particle accelerator until 27 years later.

The time span during this period is really too big.

But at the same time, it can also show how far-sighted the great and genius Einstein is!

Although Chen Muwu advanced the time of the experimental verification by five or six years this time, it still wouldn't diminish Einstein's greatness.

This experiment is easy to do, and it can produce results, which is much better than the unrealistic fantasy of teacher Rutherford.

But he couldn't explain to Cockcroft in detail the series of twists and turns behind it, so he had to make up a few lies to fool him.

Deuterium gas is too expensive and it is still a gas, metal lithium is a solid and convenient for experiments, and so on.

He said it was a lie, but Chen Muwu did not lie. These were indeed the reasons why he changed his experimental thinking, but they were only part of it.

He encouraged, or shared with Cockcroft, that we can manufacture the proton source one day earlier, and maybe we can use protons to extract the electrically neutral particle that Director Rutherford is thinking about from the lithium nucleus one day earlier. Bombarded out.

It's just that perhaps because of being too excited, Chen Muwu forgot that he had just told the matter of using this experiment to verify the mass-energy equation prematurely.

This made Cockcroft a little confused. Isn't the purpose of replacing deuterium with lithium to realize Rutherford's idea of ​​bombarding electrically neutral particles from the nucleus?

What does this have to do with the mass-energy equation?
After a few more months, after the experiment was finally completed, Cockcroft finally realized that, like Einstein, Dr. Chen also possessed the foresight of a genius.

Could it be that he had already expected that this nuclear reaction would not produce electrically neutral particles, but would only emit two alpha particles?

……

Chen Muwu devoted himself to doing experiments in Cambridge University, but outside of Cambridge University, or in other words, except for his laboratory, he was blown up because of a news report by Crowther.

In the UK, this news appeared in the science section of the first Manchester Guardian and the reprints of The Times and the Daily Mail, and few editors would classify it as a current affairs page.

This is because the British media is also controlled by the government, and the government department does not allow excessive publicity about the strike, and wants to deal with this matter coldly.

Fortunately, because it is related to Cambridge University and Cavendish Laboratory, it can also appear in the technology version.

But foreign media outside the UK don't care that much.

This kind of news worth several pounds sent back to China by a reporter stationed in London with a long-distance telegram will of course appear on the foreign news page!

The most famous school in the UK is the University of Cambridge.

The most famous laboratory in physics is the Cavendish Laboratory.

Chen Muwu, one of the two world-renowned physicists, happened to be the cause of this news.

The director of the Cavendish Laboratory and the young talent Chen Muwu want to leave Cambridge University. No one will feel sorry for this uneasy breakup, but they all want to get a share of it.

One is an old physicist with both virtue and skill, and the other is a rookie in physics who is in the limelight. If the two get together, they will be safe... greatly improving the physics level of the school.

So in addition to the University of Göttingen, which had already sent von Neumann as a guest in advance, universities all over Europe and the United States have also heard the news.

In the United States on the other side of the Atlantic, there are many universities that are not short of money, and they have long been eyeing Chen Muwu's fat.

Schulman, the former president of Cornell University who was previously the US ambassador to China, resigned after his term expired last year. He is now the US ambassador to Germany and has contributed a lot to the implementation of the "Dawwes Plan". .

Although it is difficult to obtain news from Europe in China, Schulman has always followed the news about Chen Muwu in English-language newspapers run by Westerners during his tenure in China.

Of course, domestic English-language newspapers such as "Zi Lin Xi Bao" are also willing to report on Dr. Chen.

Because he can be regarded as a link between China and Europe and the United States, and at the same time he is still half a Haining, and he is very appetizing to those Chinese upper-class intellectuals and compradors who can understand English in the concession.

After coming to Germany from China, Schulman saw all kinds of detailed news about Chen Muwu from the old newspapers collected in the embassy and the new newspapers sent in a steady stream.

He felt more and more that failing to invite Chen Muwu to study at Cornell University was the worst failure he had ever done when he was working in China, and it was even worse than dealing with the Lincheng robbery on the Jinpu Railway. .

Schulman hated Hu Shi again in his heart, who slapped his chest and promised to send Chen Muwu to Cornell.

Dr. Chen's kind of humility that most Chinese people embody is completely invisible in him. It's all a big talker!

Fortunately, God can't starve a blind house sparrow to death. He saw in the newspaper that Belfort, the Chancellor of Cambridge University, went crazy and wanted to drive Chen Muwu out of the school.

Schulman felt that Cornell University's opportunity had finally come.

He immediately sent a telegram from the embassy in Germany to Livingston Flander, who would succeed him as principal, telling him to send the letter of appointment to Chen Muwu in Cambridgeshire as soon as possible no matter what method he used.

The Cornell family is far from the only one who likes Chen Muwu.

The president of Harvard University, Abbott Lowell, and the president of the University of California, Campbell, these universities that have dealt with Chen Muwu more or less, like Cornell University, are ready to send an olive branch to Chen Muwu at the first time .

Including the brother who has never communicated directly with Chen Muwu, who can only be regarded as a long-time friend, Compton, a professor of physics at the University of Chicago, also ran to suggest to the dean of the department, Michael Sun, that he would take this opportunity to invite Chen Muwu to the University of Chicago .

Only by going to Cambridge to invite Chen Muwu can the Physics Department of the University of Chicago not be afraid of the reality of the rapid rise of other universities in physics, and still maintain its leading position in the United States.

Compton's words were somewhat self-deprecating, and Michelson felt a little uncomfortable when he heard them at first.

Oh, the Department of Physics at the University of Chicago, where I am the first American Nobel Prize winner, cannot maintain a stable position.

You have to invite the first Chinese Nobel Prize winner here to sit on Diaoyutai, right?
Is it because foreign monks can recite scriptures, or is it just that the United States is not as good as Europe, and now it is not as good as China?
Something must be done to make America great again, MAGA!

But after calming down, Michelson also felt that although Compton's remarks were a little low-key, the central idea was still good. Dr. Chen was indeed different from others.

Just one of his achievements in Cambridge in just a few years is enough for an ordinary physics professor to eat for a lifetime.

I am already very old, and I should consider retirement in two or three years. It is time to find a successor for the dean of the Department of Physics at the University of Chicago.

He originally preferred the Compton professor who came to see him today, and he mentioned this matter several times.

Compton knew that inviting Chen Muwu might cause him to lose his post as department head, but he still insisted on inviting him. This is enough to show that he is sincerely for the development of the Chicago Department of Physics.

But Michelson thought of another question, which made him, who was just happy, feel lost in an instant.

"Arthur, I agreed in principle to invite Dr. Chen to Chicago for another matter, I don't know if you remember.

"After Dr. Chen discovered Huangdixing, the National Academy of Sciences of the United States intends to award him the Watson Award.

"It should be very meaningful to give an award named after an astronomer who worked in China to a Chinese.

"However, Dr. Chen announced his refusal to accept the award shortly after the news was announced. The reason for his refusal was not his resistance to our American counterparts, but the act of refusing to enter the United States to express his respect for the restrictions on his compatriots. Dissatisfaction with the bill restricting immigration into the United States.

"I also thought before that if one day, those gentlemen in Congress abolish this unreasonable bill, Dr. Chen may come to the United States to meet all of us.

"However, shortly after Dr. Chen discovered the new planet, our overly conservative President Coolidge signed a new immigration law that was further strengthened, aiming to exclude all Asian immigrants, even those who can enter the "Washington Naval Treaty." I, who outperformed France and Italy in ", is no exception.

"Now, these politicians have completely cut off Dr. Chen's hope of coming to the United States."

The reason why Michelson remembers this incident so clearly is that in addition to being a professor of physics at the University of Chicago, he is also the president of the National Academy of Sciences.

It was Chen Muwu who was going to present the Watson Award at that time.

Michelson's words made Compton fall into deep thought.

He was obsessed with academics, and he only wanted to invite Chen Muwu to Chicago, never thinking that there were so many twists and turns behind him.

After a long while, Compton said: "Director, how about we join forces with several other universities to put pressure on Congress and ask them to abolish this decree for Dr. Chen?
"As long as Dr. Chen can be invited to the United States, even if he is evenly divided into three parts, so that he spends four months in Chicago, four months in Harvard, and four months in California, it will be of great benefit to improve our physical level. .”

"Arthur, you are too naive. This bill was signed by President Coolidge. He will certainly not oppose himself."

"Director, perhaps we can seek the help of some other people. The Secretary of Commerce, Herbert Clark Hoover, is said to be a dark horse in the current political arena, and is very popular with voters.

"And he has the experience of working in China, so he must understand the unfairness of these bills.

"It is said that Coolidge will not run for president again after the end of this term, and Hoover is the favorite to succeed him.

"If we start with the Minister of Commerce, understand the reason and move the emotion, and ask him to propose to Congress to repeal the bill that treats those Asian immigrants unequal, is this feasible?"

(End of this chapter)