As soon as Chen Muwu's side achieved positive experimental results, someone raised a discordant objection next to him, and Rutherford was certainly not happy.

Even if you're Bohr, so what?

"Nils, do you mean that Chen's experiment was done wrong, or that I said it wrong? Tell me what you think. ”

As he spoke, Rutherford's beard drooped down along with him.

"Sir, of course Dr. Chan's experiment is not wrong, because we are all here to watch. I think what went wrong was your previous hypothesis that considered 'neutrons' to be 'protons + electrons' in a coincident particle system.

"I think neutrons should be the same as protons and electrons, they are indivisible 'elementary particles'."

Bohr was not at all afraid of Rutherford's harshness, and directly said what he really thought.

Chadwick took over the topic: "But the experimental data has been laid out on the bright side, the mass of neutrons is 1.0067 units, the mass of protons plus electrons is 1.0078 units, and the binding energy between the two is about 1 megaelectron volt." Combined with the data that Dr. Chen has just measured, then the neutron as a bound state of a proton and an electron is in line with the system, which is completely compatible with the existing knowledge. ”

Chadwick is very reasonable, but his reasonableness is completely based on the fact that the experimental data measured by Chen Muwu are completely credible.

Chen Muwu did not expect that the current experimental conditions made him have to measure such inaccurate data, which became Chadwick's evidence to refute Bohr.

As everyone knows, in fact, Bohr is the most correct one.

Historically, Bohr was the first to put forward the idea that neutrons should be elementary particles, not protons and electrons, after Chadwick's discovery of neutrons.

Rutherford frowned and asked Chen Muwu, a good student who was standing beside him and was most trusted by him at this time: "Chen, what do you think of this?" ”

Chen Muwu was in a dilemma, he could not directly say that Rutherford's theory was indeed wrong, and only Bohr's conjecture was correct.

Physics is an experiment-based discipline, and experiments must be made to explain whose theory is right and whose theory is wrong.

"Well, Sizz, James, and Professor Bohr, I think it's like a husband and wife arguing, and everybody on both sides thinks they're right, otherwise it wouldn't have been a fight.

"Why don't I design an experiment and use another method to measure the true mass of neutrons more accurately?"

Chen Muwu feels that it is sometimes not a good thing to invite a group of the world's top physicists to Stockholm.

Originally, these papers of his were intended to be published in his "Journal of the Prince's College" one after another.

As a result, the academic debate between Bohr and Rutherford and Chadwick hurt him and Chen Muwu himself.

"Have you come up with a new way to experiment again? What are you going to do? ”

Not only Rutherford, but basically everyone present stared at Chen Muwu with a puzzled face, expecting what his next answer would be.

"Well, I think it's very simple, you can use gamma rays to bombard the deuterium nucleus, decompose the deuterium nucleus into a proton and a neutron, and use the energy conservation in the reaction process of this nuclear reaction to measure the mass of the neutron.

"The binding energy of the deuterium nucleus is very small, I estimate that it is only a few megaelectron volts, and this nuclear reaction is not difficult to operate.

"Well, Dr. Zhao and Dr. Cockcroft, how about the two of you going to do this experiment to measure the precise mass of neutrons?"

Chen Muwu delegated this experimental task.

Now that the neutron has been discovered, other things will not allow him to continue to do it himself.

What's more, he Chen Muwu has other things to do.

"Of course."

"Absolutely."

Zhao Zhongyao and Cockcroft agreed in unison.

Chen Muwu's ability to hand over this experimental task to them shows in itself that it is a kind of trust in them.

"Chen, what about us?"

Irena also wanted a task next to her, why didn't her brother-in-law think about her and Frederick's family first, and instead gave all the credit to two colleagues who had come to Stockholm with him from Cambridge University?

"Irena, Frederick, we are going to take advantage of Dr. Zhao and Dr. Cockcroft's experiments to write this paper on the discovery of neutrons, and then publish it in the Journal of Prince College, together with the previous papers on the discovery of the eighty-fifth element iodine and the forty-third element manganese.

"The first draft of this paper, I will work hard for you first."

"Didn't say it!"

The new task given to them by Chen Muwu not only did not make the little Curie couple unhappy, but made them full of interest.

In the whole experiment of discovering neutrons, except for Frederick's calculation of the mass of iodine-like elements before and after the nuclear reaction, everything else was done by Chen Muwu alone.

Now he asked the two of them to write their papers together, apparently wanting everyone to put their names on the final published papers.

After Zhao Zhongyao and Cockcroft, Irena and Frederick each received their tasks and left, Chen Muwu continued to entertain several guests who came from afar.

While holding up the cloud chamber photographic negatives on the table, he said politely to everyone: "I estimate that the results of Dr. Zhao and Dr. Cockcroft's experiments will still have to wait for a while to come out."

"I don't think there's any need for us to stay in the lab and wait for the results, so let's go outside and have a cup of tea first."

Although both Bohr and Rutherford wanted to know at the first time what the exact mass of the neutron was measured experimentally, who was right and who was wrong in their opinions.

But what Chen Muwu said is also very reasonable, Zhao Zhongyao and Cockcroft's experiment, it is impossible to get results in a few hours, one or two days if it is fast, and three or five days if it is slow.

Bohr thought that Chen Muwu's words about going out for a cup of tea should be the kind of English afternoon tea with hot black tea added to cold milk.

But what Chen Muwu brought up was exquisite porcelain from China, and the brews were all crystal clear green tea.

To his surprise, Rutherford, Chadwick, and Kapitsa had no problem with this, and drank the green tea without milk or sugar with relish.

"Chen, no matter how much the Royal Academy of Sciences here in Sweden doesn't want to award you the Nobel Prize in Physics again, I think it should be a sure thing for you to win another Nobel Prize in Physics this time.

"Whether it's a cyclotron or the discovery of neutrons, if you put these two feats on two people, you can get at least two Nobel Prizes in physics, but if you do them all in a short period of time, you can only get one. I feel a little bit of a loss for you. ”

He has been looking for neutrons for more than ten years, and he was discovered by Chen Muwu, Rutherford was in a good mood, he thought of Sweden, and naturally thought of the Nobel Prize.

Kapitsa also echoed: "I think this time it should not only be the Nobel Prize in Physics, but also the Nobel Prize in Chemistry should be awarded to Chen Cairight."

"When the isotope of hydrogen was discovered before, there was already a call in the market to award the chemistry prize to Chen, but the Swedish jury pretended not to hear it.

Now Chen has discovered two isotopes of hydrogen, and he has discovered two new elements that chemists who would only test ore would not be able to discover in their lifetime.

"I think it would be rude for the Royal Swedish Academy of Sciences to play dead again this time."

After taking a sip of green tea, Bohr, who felt that it was also unique without milk and sugar, also said with a smile: "I hope that they will award these two awards to Chen Muwu in the same year, so that they can create a new story." ”

Chen Muwu, who was touted by everyone, was drinking tea at this time, while frowning and staring at these cloud chamber photographs in his hand.

These negatives record the trajectory of the neutrons and hydrogen nuclei, deuterium nuclei and helium nuclei produced after the alpha particles bombard the boron crystals.

Because it is bombarded with seeds, there is no paraffin sheet behind the boron crystal to slow down the neutrons, but after the boron crystal comes out, the neutrons are directly incident in the cloud chamber.

Chen Muwu frowned fakely, in fact, he had already found what he was looking for.

He did this so that he could attract the attention of others.

As soon as he dozed off, someone brought him a pillow, and Kapitsa really noticed these strange places: "Chen, what's the matter, could it be that you have any conflict with the Nobel Prize jury in Sweden?" Why does the mention of the Nobel Prize make you so sullen? ”

"Peter, it's not a Nobel Prize, since I won it once, I've been very open to seeing if I can win it again.

Of course, that doesn't mean that I don't like to win the Nobel Prize, after all, the real prize money and the medal made of pure gold are still very tempting.

"What makes me frown is actually something else."

As he spoke, Chen Muwu put a certain photographic negative in his hand on the coffee table surrounded by everyone.

He stretched out his index finger and pointed to a trajectory on the negative and asked, "Come and see, isn't this trajectory here?"

"If you look at the direction of its deflection in the magnetic field, it should be a positively charged particle.

Comparing its trajectory with that of hydrogen, deuterium, and helium, it turns out that it does not belong to any of the three nuclei.

"When I look at its trajectory, I always feel that it should be an electron trajectory. Then the problem arises, this electron belt seems to be positively charged. ”

Last summer at the Cavendish Laboratory, Chen Muwu discovered the existence of positrons at the same time in his own experiments to discover neutrons.

As for where do positrons come from?

Of course, it is the nuclear reaction between the alpha particles and the boron-10 in the boron crystal, which produces nitrogen-13 and releases a neutron.

Nitrogen-13 is not a stable isotope of nitrogen and has a half-life of less than ten minutes.

Nitrogen-13 undergoes positive beta decay, releasing a positron outward, which then becomes stable carbon-13.

α＋B→n＋N。

N→β＋C。

At the Cavendish Laboratory, there was a paraffin block behind the boron crystal that proved that the protons would be bombarded by neutrons, and the positrons were still able to penetrate through the paraffin block and enter the cloud chamber.

Now that the paraffin mass behind the boron crystals has disappeared in Stockholm, the positrons that enter the cloud chamber through positive beta decay through nitrogen-13 are much more unimpeded.

It's just that when calculating the mass of neutrons using cloud chamber photos, all eyes were on the neutron, and no one noticed this positively charged electron trajectory.

After Chen Muwu pointed to the trajectory of the photographic negative, the shock brought by this positively charged electron to the physicists present was no less than that brought by the electron that had just been confirmed to be discovered.

Especially Bohr, when he heard the positively charged electrons from Chen Muwu's mouth, he immediately remembered a past.

It was in Copenhagen in 1924, when Chen Muwu was invited by him to leave Cambridge University for an exchange visit to the Institute of Theoretical Physics.

That time, Chen Muwu and Pauli not only moved their fists in Copenhagen, but also made a bet that the positively charged electron predicted in Chen's equation exists or not.

Bohr remembers that the bet between Chen Muwu and Pauli was ten pounds.

Some time ago, Pauli had triumphantly told himself that the two of them had multiplied their bet by eight hundred times, from ten pounds to eight thousand pounds.

At that time, he himself had advised Pauli not to take the risk.

However, Pauli felt that Chen Muwu would definitely lose, and regarded his exhortation as the wind in his ears, and did not take it to heart at all.

Unexpectedly, how long has it been, and Chen Muwu has found a positively charged positron!

Hearing is false, seeing is believing.

Bohr leaned forward to witness the trajectory of the positron from the photographic negative.

As for Chen Muwu, he has already begun to pick up a ruler and a pen and paper to measure and calculate the relevant data of the particles corresponding to this trajectory.

His operation cannot be said to be a snake addition, but only rigorous.

But whether it is Rutherford, Chadwick or Kapitsa, in fact, they don't have to wait for Chen Muwu's calculation results, they can see that this is an electron, but it is an electron with a positive charge.

originally thought that Chen Muwu's discovery of neutrons was already a remarkable achievement.

Unexpectedly, he not only discovered the neutron, but also piggybacked on the positron to get out.

Just said that there are cyclotrons and neutrons, and the Nobel Prize jury should once again send the Nobel Prize to Chen Muwu's hands.

Now it seems that if Chen Muwu's name is not on the list of winners next year, Rutherford is ready to go to the Royal Swedish Academy of Sciences to find someone desperately.

(End of chapter)