1900: A physics genius wandering around Europe

Chapter 639 A Scientific Couple! Luck Strikes! Artificial Radioactivity! Uncle Bruce, I Did It!

France, Radium Institute.

Elena's current research topic is radioactivity.

Her research on radioactivity went far beyond what was studied during Marie Curie's time.

For example, she often likes to ask others a question that seems very simple.

In the periodic table, what kind of elements can be called radioactive elements?

Many people found it unbelievable after hearing it.

Is there even a need to ask this question?

"Of course, any element that can emit radiation is a radioactive element."

Whenever this happens, Elena patiently explains:
"wrong!"

"This statement made sense before the concept of isotopes existed."

"But now, that statement is incorrect."

"We know that almost every element in the periodic table has its isotopes."

"Isotopes are elements that are in the same position."

"Because isotopes differ only in the number of neutrons, but have the same number of protons, they occupy the same position in the periodic table."

"For example, element number 6 [carbon] has several isotopes such as C12, C13, and C14."

"Element 88, radium, has a greater number of isotopes."

"Interestingly, carbon isotope C14 is also radioactive, but we do not call carbon a radioactive element."

"Why is this?"

"Because only elements without stable isotopes are called radioactive elements."

"For example, radium is a radioactive element because all of its isotopes are unstable and radioactive."

"Although carbon has a radioactive isotope C14, C12 and C14 are stable isotopes, so it is not a radioactive element."

After hearing the explanation, everyone suddenly understood.

In the later periodic table, there are a total of 118 elements.

Among them, element 43 (technetium), element 61 (promethium), and all elements above element 83 (bismuth) are radioactive elements.

Starting with element 95, americium, all of them are man-made elements and do not exist in nature.

Note that artificial elements and artificial isotopes are not the same concept.

Although elements before number 95 are all naturally occurring in nature, some of their isotopes are not naturally occurring and are man-made.

At this point in time, although the periodic table is not yet complete, physicists have already discovered that all radioactivity is a natural, spontaneous radioactive behavior.

Therefore, many people believe that radioactivity is an inherent property of elements and cannot be interfered with.

However, Rigdwell raised the possibility of artificial radioactivity.

The shock this caused Elena was unimaginable.

When Marie Curie first heard this conjecture, she solemnly said:

"This is a risky but worthwhile subject to study!"

However, Joliot had his doubts.

"Although Professor Bruce's proton-neutron model can theoretically explain the nature of radioactivity."

"But this does not prove that radioactivity can be produced artificially."

"After all, the theory can only explain the nature of radioactivity, but cannot describe the details of the radioactive process."

In the field of nuclear physics, radioactivity specifically refers to the phenomenon of emitting three types of rays: alpha rays, beta rays, and gamma rays.

The origins of the three types of radiation can be explained by the proton-neutron model of the atomic nucleus.

Alpha rays are formed when an atomic nucleus emits two protons and two neutrons to form a helium nucleus.

Beta rays are a stream of electrons emitted when a neutron in an atom's nucleus transforms into a proton.

Gamma rays are electromagnetic radiation produced when a special transition occurs inside the atomic nucleus.

It is clear that there is currently no theory or experiment to prove how these three types of rays are specifically produced.

However, Elena firmly believed in artificial radioactivity and offered her own perspective.

"I believe that the essence of exploring artificial radioactivity is to create artificial isotopes."

"The naturally occurring radioactive elements discovered today are mainly heavy elements with high atomic numbers: such as radium, uranium, and thorium."

"Light elements like C14 are only found to be radioactive in cosmic rays."

"Most light elements have not been found to be naturally radioactive."

"So, if we can artificially create isotopes of certain light elements, we might be able to obtain radioactive isotopes."

Jolio was convinced instantly.

Irene's logic is simply impeccable.

Since cosmic rays contain naturally occurring radioactive isotopes such as C14.

If they were to create an isotope of nitrogen, could it also be radioactive?

From that moment on, he was determined to help Elena accomplish this feat!
However, it is extremely difficult for experimental physics to succeed!
They encountered the same problem as Cockraf.

That means there's only a direction, but no specific method.

Therefore, we can only try them one by one.

Unlike Cockraf, Elena chose to bombard with alpha rays.

Because it contains two protons and two neutrons, it is easier to form isotopes.

With Jolio's comfort, Elena recovered from her anxiety.

Cockraf's success is well-deserved, and she should be happy for him.

Irene had met him before; he was a very polite gentleman.

Therefore, she quickly threw all her energy back into her work.

This day, inside the laboratory.

Elena opened today's experiment plan and said:
"Oh, today we're going to do an experiment with alpha rays bombarding aluminum foil."

"Honey, I think we might have wasted a whole day."

As Jolio fiddled with the instruments, he said with a smile:

"What's the point of this?"

"The experiment hasn't even started yet, how do you know it will fail?"

In Joliot’s mind, Irena was a bit oblivious and often gave people the impression of being silly and clueless.

Combined with her talent, this creates a strikingly contrasting sense of endearing naivety.

For example, not long after entering the lab, he started talking nonsense.

However, Elena explained:

"Because this experiment has already been done by many people."

"The experiment of bombarding aluminum foil is probably the most classic experiment in the field of atomic physics."

"Could there be any new discoveries?"

Jolio shook his head, disagreeing with her point of view.

I don't think so.

“Look at Cokrav, he simply increased the energy of the proton and successfully achieved artificial nuclear fission.”

"This shows that any change in even a tiny factor can affect the experimental results."

“In the past, when people conducted experiments on bombarding aluminum foil with alpha rays, they generally used the radioactivity of radium or uranium to generate alpha ray sources.”

"Then can we try a different source?"

"For example, using polonium or radon to produce alpha rays?"

Upon hearing this, Elena's eyes lit up.

"what?"

"I've really rarely seen similar research and papers."

"Yorio, you have quite a few ideas."

Jolio chuckled foolishly.

"These are all lessons I learned from Marie Curie."

He subtly flattered her.

The two of them got right to work.

The Radium Institute is indeed powerful; it has a complete range of radioactive materials that are extremely rare and hard to find elsewhere.

Elena quickly sourced radioactive elements such as polonium, radon, actinium, thorium, and protactinium, preparing to give the experiment a major upgrade. They started by using polonium as the radioactive source.

The experimental setup is very simple:
A container is filled with polonium, and its alpha rays are controlled by an electromagnetic field.

Place an aluminum foil at a certain distance in front of the container, and adjust the thickness of the aluminum foil so that the alpha rays can be completely absorbed.

There is a fluorescent screen behind the aluminum foil, and the fluorescence can be observed through a microscope once a particle hits it.

Obviously, under normal circumstances, the screen will not light up.

Because the alpha rays produced by polonium cannot penetrate aluminum foil and therefore cannot reach the fluorescent screen.

This is the same device that Rutherford used to discover the proton.

However, he filled the container with nitrogen gas. When the alpha rays collided with the nitrogen nuclei, protons were produced, and these protons could penetrate the aluminum foil.

So he saw fluorescence through the microscope.

But now, Elena's experiment is to see if it's possible to make aluminum itself radioactive through impact.

Before the concept of nuclear reaction was proposed, this idea would have been considered a complete fantasy.

"This is insane! Absolutely insane!"

But now, Elena is very confident about it.

If aluminum foil doesn't work, try iron foil or gold foil, one by one according to the periodic table.

At this moment, she and Jolio were wearing full protective suits to avoid radiation from the rays.

This is also the first protection method proposed by Professor Bruce.

The scientific community is increasingly aware of the harmful effects of radiation.

The previous trend of valuing radioactivity has also begun to be curbed.

Snapped!
The experiment begins!
Elena first removed the aluminum foil and quickly observed fluorescence on the fluorescent screen.

This indicates that polonium is stably emitting alpha rays.

Then, she put the aluminum foil in, and the fluorescence on the display screen immediately disappeared.

Clearly, the alpha rays were blocked by the aluminum foil.

Elena sighed inwardly; it seemed the experiment was destined to fail.

However, Joliot remained silent and observed from the side.

"Don't rush, wait a little longer."

Elena then quietly observed the experiment.

After all, using polonium as a radioactive source is rare, and complete documentation is indeed necessary.

Soon, Elena's expression suddenly changed!
"what?"

"Yorio, did you see that?"

"The screen seemed to flicker just now!"

Is aluminum foil really radioactive?

"My God!"

"Could it really have succeeded?!"

Elena was so excited she didn't know what to do.

Even through her protective suit, I could imagine her joyful expression.

Jolio remained calm throughout.

"uncertain."

"It's possible that the thickness of the aluminum foil is not precise enough."

"Under prolonged bombardment, some alpha rays passed through the aluminum foil, thus producing fluorescence."

Upon hearing this, Elena nodded.

This conjecture is not without merit.

She immediately came up with a verification plan!
"Turn off the alpha ray source and see if the fluorescence is still there."

After saying that, she covered the polonium with a cover so that the alpha rays it emitted could not escape.

Something magical happened!

After removing the alpha rays, Elena and Joliot were surprised to find that the fluorescence was still present!

This is incredible!
Even the usually composed Joliot was excited.

"The fluorescence is caused by changes in the aluminum foil itself."

"At this moment, the aluminum foil is emitting some kind of substance that hits the fluorescent screen, thus producing fluorescence."

"My God!"

"The aluminum foil really is radioactive!"

At this point, the two of them went completely mad!
They looked at each other and saw endless emotions in each other's eyes.

But now is not the time to celebrate.

The two immediately demonstrated the basic qualities of experimental physicists:
Record every experimental phenomenon meticulously.

They found that the intensity of the fluorescence decreased over time until it disappeared completely.

This indicates that the radioactivity produced by the aluminum foil must have a very short half-life, so it quickly decays into a stable element.

They then repeated the experiment several more times and found the same phenomenon.

At this point, the two could be certain that they had indeed discovered artificial radioactivity.

Jolio was so excited he didn't know what to say.

His earlier suggestion to change the radiation source was merely to comfort and encourage Elena; he didn't actually believe it was a good idea.

But Elena was like a lucky charm.

They turned an ordinary experiment into a groundbreaking one!

Without a doubt, this is a Nobel Prize-worthy achievement.

Joliot knew very well the sensation this result would cause in the physics community.

Irene burst into tears of joy, hugging Jolio tightly as she tried to release the mix of grievances and happiness she felt.

Jolio gently patted her back, his face beaming with joy, but in his heart he was thinking: Now we can have a happy wedding.

If it weren't for his sudden inspiration to use polonium as a radioactive source, Elena might not have been able to discover artificial radioactivity.

He is fully qualified to say:
"I am the man behind Elena."

Later, when others asked him:

"Yorio, what wedding gift did you give Elena?"

Joliot said nonchalantly: "It's nothing, just a Nobel Prize."

After Elena and her companion finished organizing the experimental data, they went to find Madame Curie.

She wanted to share this joy with her mother as soon as possible.

After reviewing the experimental data, Marie Curie was so amazed she could hardly contain her smile.

"Congratulations."

"This is a remarkable achievement in the field of nuclear physics!"

Marie Curie, being a top figure among top figures, reminded her:

"I think your next step should be to continue studying the mechanism of the radioactivity of aluminum foil, and what kind of rays it emits."

Elena hugged her mother tightly and said: