Reborn and become a Great Scientist

Chapter 339: 78 There is an extra track
The climate in the UK is a temperate maritime climate, with no severe cold in winter and no scorching heat in summer, but there is slightly more rainfall throughout the year.

No wonder the gentlemen in suits and top hats walking on the street are either holding sticks or umbrellas in their hands.

This is different from the subtropical monsoon climate in Sihai. For the old lady of the Chen family who has just arrived in Europe, it is a very novel life experience.

There is no annoying rainy season, and there are no more annoying typhoons. Although the temperature in summer is hot, it will not be as hot as Sihai.

——Not to mention that British food is not that delicious, but the temperature and humidity in summer are indeed slightly more suitable than before.

But this is for the Chen family who have always lived at the eastern end of the Eurasian continent. For the British people who have lived on the island for generations, including Chen Muwu who has become accustomed to living here, the British summer is still too hot. very.

In Cambridgeshire, the sections of the Cam River where the current flow is relatively gentle, and the willow trees on the shore, are crowded with local residents and international students who come to swim in the river and escape the scorching heat.

The cicadas on the willow tree also kept chirping.

Chen Muwu, the acting director of the Cavendish Laboratory, "hides in a small building and becomes a unified body, caring about winter, summer, spring and autumn."

He also deliberately closed the heavy curtains in his laboratory, leaving only a lamp in front of the camera that captured the photos of the cloud chamber, and quietly waited for the arrival of neutrons.

The cloud chamber, which Blackett had improved a few years earlier, could take many photos per minute.

At that time, Blackett came to Chen Muwu for help with a pile of cloud room photos because he was conflicted between taking too many photos and not looking at the photos quickly.

And that time, Chen Muwu fulfilled his mission and successfully found traces of artificial nuclear transmutation recorded for the first time in one of the many photos.

Now the more fun Chen Muwu takes in taking photos, the more painful it will be for him to enjoy looking at the photos.

Because no matter how many photos were taken, this time there was no Blackett or Kapitsa to help look at the photos. He had to do all the work by himself.

Therefore, Chen Muwu thought that he would take fewer pictures at the beginning, so as not to be overwhelmed when he faced several stacks of photographic negatives.

I hope he can get into the spirit immediately, and can directly find the photo of the proton he wants without having to fine-tune the experimental equipment, including the accelerating voltage.

Because the light in the laboratory was very dark, Chen Muwu did not go to any darkroom, but directly separated an area inside where he could take and develop photos in the cloud room.

After the first batch of photographic films were developed, Chen Muwu couldn't wait to search and inspect them one by one.

The good news is that in the first batch of photos, there are already spiral-shrinking tracks.

According to the direction of the magnetic field, the particles corresponding to this trajectory should be positively charged.

But "Misfortune lies where blessing lies, and misfortune lies where misfortune lies." Where there is good news, there is often bad news.

Bad news, or for Chen Muwu, it doesn't seem to be bad news.

All in all, there is more than one spiral shrinking trajectory, and their shrinking directions are exactly the same.

In other words, he discovered two different positively charged particles in a certain cloud chamber photographic plate he took.

Judging by the thickness of the trajectory, one has high mass and the other has low mass.

There is no need to observe carefully, let alone hold a ruler and pen and paper to measure and calculate the charge-to-mass ratio of these two positively charged particles.

Director Chen was just confused for a second or two, and then he figured out what the two things were.

The one with the larger mass is of course the proton he is looking for, which is what is produced when neutrons bombard the paraffin block.

As long as this proton exists, it means that Chen Muwu has successfully bombarded neutrons from the boron crystal with accelerated alpha particles.

In other words, he has successfully completed his intended goal and mastered the means to "accidentally" bombard neutrons in the future.

And the one with the smaller mass is——

Positron.

Boron has two isotopes that exist stably in nature, namely boron-10 and boron-11. The abundance of the former is 20.00% and the latter is 80.00%.

Bombarding these two isotopes with alpha particles can produce neutrons, but the other products in this nuclear reaction are somewhat different.

After the alpha particle is bombarded with boron-10, a neutron will be emitted, followed by nitrogen-13.

Nitrogen-13 is an unstable isotope of nitrogen with a half-life of less than 10 minutes. It then undergoes positive beta decay, releasing a positron and becoming stable carbon-13.

Positrons come from here.

The energy contained in the protons knocked out of paraffin by neutrons is 5.7 MeV.

During the positive beta decay of nitrogen-13, the positrons released have an energy of 1.2 MeV.

Although it seems that the energy of positrons and protons is several times different, their rest masses are also quite different.

If you substitute it into Einstein's relativistic mass-energy equation, in fact, the speed difference between the two is basically not that much different. Compared with the speed of light, the difference is basically just a few decimal places.

Even if the positrons produced by the decay of nitrogen-13 may have to pass through or bypass the paraffin block blocking the back, before they can enter the cloud chamber and be recorded by the camera, the probability will be much lower than that of protons.

But who made Chen Muwu the chosen one? In this experiment, not only did he eject neutrons and positrons from boron-10, but he also allowed two newly generated new particles to enter directly or indirectly. When we arrived in the cloud room, we were photographed and recorded on film.

In the original time and space, positrons were first observed at the California Institute of Technology by Chinese physicist Zhao Zhongyao, who studied with Nobel Prize winner Millikan.

But he did not pay attention to and analyze this result carefully that time, so he missed the discovery of the positron.

However, Zhao Zhongyao's work cannot be said to be without contribution. He inspired Anderson, his junior student who was doing experiments in the same laboratory with him, and asked Anderson to discover it two years later in 1932 - that is, when he and Chadwick discovered the In the same year of the [-]s, the shadow of positrons was found for the first time in the tracks left by cosmic rays in the cloud chamber.

Unlike Chen Muwu this time, Anderson found positrons directly from cosmic rays, and he will also find muons in cosmic rays in the future.

This was a complete surprise for Chen Muwu. While bombarding boron-10 with alpha particles to obtain neutrons, he also obtained nitrogen-13 that can produce positive beta decay.

Nuclear physics can be said to have been founded in 1911. After the gold foil experiment, the atomic nuclear model proposed by Rutherford proposed the existence of the atomic nucleus.Later, he also used alpha particles to bombard nitrogen nuclei and discovered protons, one of the materials that make up the nucleus.

But the turning point in nuclear physics undoubtedly occurred in 1932 in the original time and space.

This year, people discovered deuterium, the first isotope of hydrogen, found neutrons, another substance in the nucleus, and also found strange and unusual positively charged electrons.

However, in the current time and space, deuterium had been discovered under low temperature conditions by Chen Muwu in the David Faraday Laboratory under the old Bragg two years ago.

Two years later, he found positrons as well as neutrons.

Originally the three important discoveries of nuclear physics in 1932, they all now belong to Chen Muwu himself.

Deuterium was discovered just after Chen Muwu won the Nobel Prize in Physics, so it would be fine if Sweden did not award him another Nobel Prize in Chemistry. I wonder if they will give him another Nobel Prize in Chemistry in the future because of this matter.

But the two discoveries of neutrons and positrons are each worthy of physics prizes.

The physics prize in 1935 was awarded to the neutron, and the following year in 1936 it was awarded to the positron.

However, these two discoveries in nuclear physics brought more than just two physics prizes.

The positron was discovered in the second half of 1932, which verified the existence of the positron predicted by Dirac through his own equation. In 1933, the Nobel Prize jury was very timely and awarded the Nobel Prizes in 1932 and 1933 respectively. Awarded to Heisenberg, as well as Schrödinger and Dirac.

These are four Nobel Prizes and five golden medals!

Chen Muwu feels that when he "discovers" neutrons and positrons in the future, the Royal Swedish Academy of Sciences, no matter how reluctant it is, will definitely have to consider awarding Chen Muwu his second Nobel Prize medal.

But it is very likely that the three achievements of "neutron discovery", "positron discovery" and "proposing quantum mechanical equations and predicting the existence of positrons" will be lumped together, and only one medal will be awarded to him, just like Chen Muwu's first When he won the Nobel Prize for the first time.

In the original time and space, the physics prizes in 1931 and 1934 were originally missed because there were no valuable physics discoveries. Now he has gathered together these discoveries that can be awarded several times in the future.

How the future Nobel Prize in Physics should be awarded and who should be awarded it now seems to be completely confusing.

Oh, no matter what, let’s talk about the rest later!

But speaking of the three young theoretical physicists, the award was due to the discovery of the positron predicted by Dirac. Chen Muwu thought that when he was working under Bohr in Copenhagen, he also predicted the existence of the positron. .

But his theory was too advanced and no one could accept it. Chen Muwu was not only ridiculed by Pauli, but also made a bet with his defeated general, saying that as long as the existence of positrons was discovered in the future, Pauli would Li will pay Chen Muwu and ten British Sovereign gold coins equivalent to ten pounds.

This amount of money was not a big sum of money for Pauli, who was still a student studying with Bohr in Copenhagen.

For Pauli, who is now a professor of physics at the University of Berlin, it is even less important.

It was worthless in Pauli's eyes, and even less valuable in Chen Muwu's case.

However, Chen Muwu didn't expect to make a fortune through this bet. He just wanted Pauli to admit his mistake and disgusting person.

Now that he has thought about this matter, Chen Muwu must write a letter to Pauli and send it to Berlin, Germany, together with the physics journal in which the paper is published, when a paper on the discovery of neutrons and positrons is published in the future.

The witnesses of that bet at that time were Bohr, Heisenberg and Oppenheimer.

Chen Muwu couldn't say whether Bohr preferred himself, a rising star, or Pauli, one of his smartest students.
But Heisenberg and Oppenheimer are now on their own side.

Thinking of the bet and Pauli's Jewish identity, Chen Muwu suddenly smiled knowingly. He felt like he was Antonio who finally won in "The Merchant of Venice", and Pauli was the villain Charlotte.

Pauli was, of course, a great physicist, but not a very good character.

The lower you lower your stature for this kind of person, the more he will push forward.

Only by completely convincing him can he be used by me.

Not long after, they have already entered the political stage in Germany, gradually pulling on the mustache of a powerful force, and will hold their third party congress in Nuremberg.

Then their strength will rapidly expand until they finally dominate the entire Germany.

At that time, instead of letting Pauli run to America in advance, it would be better to trick Pauli into going to Sweden like everyone else.

Chen Muwu was as fast as ever in conducting experiments. It only took a few days from setting up the experimental device with equipment to finally taking photos of protons and positrons.

Now that you have found the results you want, it no longer makes sense to continue the experiment.

After carefully putting away the several photographic films, Chen Muwu disassembled his devices one by one and placed them back in the warehouse of the Cavendish Laboratory.

He planned to stay in Cambridge for a while longer and write some outlines for Eve about science fiction novels about aliens.

After Chadwick comes back early, he will visit his home in London.

On August 1927, 8, U.S. President Coolidge came to Mount Rushmore near Keystone, South Dakota, and delivered a speech on a makeshift podium, praising the four presidents Washington, Jefferson, Lincoln and Theodore Roosevelt. He made great contributions to the United States at different times, and announced the federal government's support for the heads of four American presidents engraved on Mount Rushmore behind him.

At the end of his speech, Coolidge handed a set of drill bits to the sculptor Gerzon Borglum. After receiving the drill bits, Coolidge climbed to the top of the mountain and drilled the first hole above Washington's head.

On the same day, the French House of Representatives voted to repeal a previous law.

This law once stipulated that if a French woman married a foreigner, she would automatically be deprived of her French citizenship.

This law once prevented French women from marrying Chinese workers in France after World War I. However, many people would rather give up their French citizenship and marry Chinese workers.

The repeal of this law actually inadvertently benefited Chen Muwu, preventing Eve from changing her nationality to Poland after the wedding next year, or simply getting a Nansen passport.

Also on this day, Chen Muwu received a letter from China.

The letter was stamped with the postmark of Tong Jing, and the name of an institution was printed on it, National Government College.

(End of this chapter)