We bring to your attention an interview with the Scientific Leader of Flerov Laboratory of Nuclear Reactions JINR Academician Yu. Ts. Oganessian for Ogoniok magazine, published by Kommersant.ru.

“Creation of world can be reproduced in Dubna”

Academician Yuri Oganessian explains why new superheavy elements are needed

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Ogoniok magazine No. 47 02.12.2019, p. 28

Photo: Dmitry Lebedev / Kommersant

Why do we need new elements that few people know about except nuclear physicists who put them in the Mendeleev’s Periodic Table? Academician Yuri Oganessian, who has devoted his life to the hunt for new elements, explained to Ogoniok that this was our chance to unravel the structure of the world. At the same time he explained how this knowledge would change it.

Interview by Elena Kudryavtseva

Ogoniok, as part of a joint media project with the Skolkovo Institute of Science and Technology, continues publishing a series of interviews with leading Russian physicists. No. 37 in 2018 featured a conversation with Vladimir Zakharov; No. 39 in 2018 with Ildar Gabitov; No. 45 in 2018 with Valery Rubakov; No. 2 in 2019 with Albert Nasibulin; No. 11 in 2019 with Alexei Starobinsky; No. 20 with Lev Zelyony; No. 23 with Mikhail Feigelman; No. 30 with Alexander Belavin; and No. 38 with Valeriy Ryazanov.

Russian physicists are ready to start synthesising the 119th and 120th elements of Mendeleev’s Periodic Table. The answer to the question “why?” is that it will expand our knowledge of matter and possibly correct Mendeleev’s periodic law itself in the area of superheavy, undiscovered elements.

What is needed to solve this problem? A new laboratory, called the Superheavy Element Factory, has already been built at the Joint Institute for Nuclear Research in Dubna, Moscow Region. It doesn’t really resemble a factory, though. Thousands of intricately curved pipes of various diameters that connect the parts of the facility create a technological geometrical pattern, resembling images from science-fiction films. Three halls with a high degree of radiation protection contain the latest experimental equipment – various facilities with magnets, cameras, detectors… The centrepiece of the Factory is the new accelerator DC-280. The experiments that are being planned here also seem quite science-fiction: scientists are going to produce nuclei of elements that do not and never have existed in nature. At their facility, tens of trillions of nuclear reactions take place every second. To obtain the new substance, scientists bombard the “target” nucleus with “projectiles” nuclei . The projectiles are accelerated to an incredible speed of 25,000 km/s and then smashed into a spinning wheel with sectors of titanium foil onto which milligrams of target substance are deposited. The separator divides the light atoms, like a fine sieve, from the heavy elements, especially from the superheavy elements, which are of such interest to physicists. The difficulty is that the formation of a new element is a rare process, so sometimes we have to wait years for a result. The beam intensity has the biggest impact on efficiency. The new accelerator has ten times the beam intensity of previous accelerators. In order to test the operation of the new machine, Dubna is ready to reproduce the experiment with the previously discovered 114th and 115th elements (flerovium and muscovium) and then go further. Future experiments in Dubna will be an important challenge to the modern theory of nuclei and atoms.

What Yuri Oganessian is known for

— Yuri Tsolakovich, scientists know about 118 elements – from hydrogen to oganesson. Over the past 15 years, five new elements have been synthesised in Dubna, and Russia is now the leader in this scientific field. Would you explain why the work had to be interrupted and a new mega-facility had to be built to find the further elements?

— Because we wouldn’t have done anything new on the old one. In terms of its parameters, particularly the production of superheavy atoms, Factory surpasses everything in the world in this field. This opens up new opportunities both in the synthesis of new elements and detailed investigation of their properties. For example, we used to get an average of just one atom of element 118 per month. The Factory, in turn, will make it possible to produce dozens of atoms. We also plan to study other recently discovered elements – copernicium (112), flerovium (114), and moscovium (115) – about which little is known yet.

It is believed that elements 113-118 can clarify the formation of elements in nature, while the synthesis of elements 119 and 120 will allow us to discover the eighth row of the Mendeleev’s Table and move on to even heavier elements.

We don’t know anything about them yet. Perhaps these elements will open up an unknown and vibrant area of chemistry. But to get there, we need to develop new approaches to obtain them and study their properties.

— What is the fundamental difficulty in obtaining next elements?

— The situation is really like this: the heavier the element, the harder it is to get. To create the nucleus of a new element, the interacting nuclei of the projectile and the target must merge with each other, become one. To do this, they need to get close enough to each other for the short-range nuclear forces to be activated, in other words, for a strong interaction to occur. For this, the projectile nucleus must first be accelerated to a remarkable speed, 0.1 the speed of light, to overcome the repulsion of the two positively charged nuclei, the target and the projectile. The main problem today is that we are using artificial elements heavier than uranium as targets, which are produced in nuclear reactors with a high neutron flux. There are two such reactors in the world. One is in Oak Ridge, USA (Editor’s note: this is where plutonium for the US atomic bomb was first produced), the other is here in Dimitrovgrad, Ulyanovsk Region. But the heaviest element that can be produced at these reactors in the necessary quantity is californium (element 98). (Editor’s note: Californium-252 is the most expensive industrial metal in the world, one gram of it costs four million dollars.)

— Do you now need to change your projectile?

— Yes, that’s right. We got element 118 from the fusion of calcium and californium nuclei. Now instead of the extremely effective calcium, a heavier element has to be taken. Next on the Mendeleev’s Table is titanium, but with it, as we have seen, the efficiency of producing the superheavy elements drops immediately.

— But now you will be using exactly titanium at the Factory?

— Yes, we hope to get the 120th element by colliding titanium with californium. A californium isotope target is already being prepared by our colleagues at Oak Ridge National Laboratory (USA). We will then use the fusion reaction of titanium with berkelium to produce the 119th element. Berklium is more difficult to work with, it disintegrates quickly: halves in 320 days!

Treasure Island

— You mentioned the stability island that physicists have been dreaming of getting close to for decades. What does it represent?

— At first it was a theory that was, without exaggeration, being created in the late 1960s by every theorist in the world. Until then, it had long been considered that if one moved from uranium, an element with order number 92, to elements with higher numbers in the Periodic Table, their lifespan would rapidly decrease. And as early as the 100th element, they will cease to exist. This movement was believed to lead to the limit of existence of the material world.

However, the new theory implied that far beyond the then known heavy radioactive elements, where according to the old theory nuclei could not exist, there would be a large region of so-called superheavy elements, much more stable than their lighter predecessors.

— So they could theoretically exist in nature?

— Yes, that’s right. Following these predictions, there was a worldwide sensation: superheavy transuranium elements were sought in cosmic rays, in meteorites, in lunar and terrestrial samples. Scientists tried to synthesise them in powerful nuclear reactors. Then in massive nuclear explosions (five were attempted in the USA). Unfortunately, these efforts have not yielded results.

— When did they start to be synthesised on accelerators?

— At the same time, other major nuclear physics laboratories around the world were conducting experiments on the artificial synthesis of hypothetical superheavy elements. We were busy with this problem too. But 15 years of hard work also came to nothing. By analysing the reasons for the failures, we decided to fundamentally change the approach to synthesising superheavy elements. We realised: due to the fact that the cherished region (the stability island of the superheavy elements) refers to nuclei with a large excess of neutrons, we simply cannot reach this treasure island with our means.

We need to change the projectile and target material. An indication that we have indeed landed on the island will be the sudden rise in the lifespan of this heavyweight. But this requires having the maximum available excess neutrons in the projectile and target nuclei. So we decided to use the rare isotope calcium-48 as the projectile nucleus. If the most common isotope calcium-40 contains 20 neutrons, calcium-48 has 8 more. This isotope is extremely rare and expensive.

— The vice-president of the Royal Society of London recently released a video of a clear vial of white powder and said it was one of the most expensive substances on Earth: six grams of calcium-48 worth a million and a half dollars.

— We produce calcium-48 in the city of Lesnoy, near Yekaterinburg. In the first attempt to produce a beam of calcium-48 ions and the first experiment with it to produce element 102, we saw the full benefit of this projectile. But the huge consumption, about 40 milligrams per hour, in our facility excluded its use for superheavy elements synthesis, we simply would not have managed with such costs. By the early 1990s, however, we had an idea of how we could set up an experiment to synthesise the 114th element. But the situation of science at that time was appalling. I remember visiting G.N. Flerov’s wife, who was also a physicist (he himself was gone by then), and when she asked what we were going to do next, I said: “We are going to synthesise superheavy elements. I will do my best to synthesise the 114th element, and if it succeeds, I will name it after Georgy Nikolaevich.” She looked at me attentively and said: “You are out of your mind, what new elements at this time!” Nevertheless, we decided to begin our challenging journey. But to do this, we had to literally start from scratch and completely re-equip our laboratory.

— An ingenious solution for the early 1990s. Where did you get the expensive components – the projectile and the target?

— Together with my deputy and colleague Mikhail Itkis, we went to see Valentin Ivanov, Deputy Minister of Minatom. We explained that we had an idea of how to synthesise superheavy elements, but we did not have the materials and the means. But we are, you see, very enthusiastic. It was exactly about calcium-48 and targeting materials. Ivanov did not question us, but called Dimitrovgrad and said: “Don’t give away all the transuranium materials we have, we’ll be getting superheavy elements”.

Getting up the courage after conversations at Minatom, I went to America to visit our competitors at Berkeley and Livermore laboratories, and later to Oak Ridge, where the national laboratories of the US Department of Energy are located. I offered them cooperation by saying that I would explain the essence of our idea and if they showed that it could be done better at their place, we would come to them, and if it was better at our place, they would have to come to us. They said: no need to explain anything, we are coming.

— What did you need from them?

— We needed from them a target matter for the experiments. Specifically, plutonium. However, not plutonium-239, which is used at NPP to generate electricity, but a different one, which has an even heavier mass, plutonium-244, with five extra neutrons.

— Did they produce them in Russia?

— No, they did not. Then it turned out that it was possible to conduct the experiment on plutonium-242, which we had, but then we were not sure that it would work even on 244, so we decided to be on the safe side.

— And how did you organize the transportation of plutonium from the USA?

— That’s quite a story, we could make a film about it, but it’s better not to mention the details, we’ve been through enough as it is.

— You wouldn’t carry plutonium on a passenger plane!

— It turns out that sometimes you can… But the story of the calcium-48 ion source for the calcium beam is more intriguing. We bought the ion source from the French, who were making it for their own needs. According to my estimates, this unit should have been very suitable for producing calcium-48 ions. But when we got the French source, it turned out that it produced ions from solid calcium 10 times less than from gases. Well, calcium has no gaseous compounds. Then we modified it extensively and brought the source up to the level of gaseous substances. There was a minor scandal: a French source works significantly better in Russia than in France! Their managers, understandably, called their engineers to account. We had to intervene and suggest that they incorporate our adaptations into their sources.

— A rare practice in science, where the competitive spirit is strong.

— In fact, when you start keeping secrets, it means you’re not going to create anything better. Instead, you have to keep moving forward and making new things.

The new plasma source gave 0.5 instead of 40 milligrams per hour. Consumption has been reduced by a factor of 100!

— As a result, flerovium, the first element, was obtained in your laboratory in 2000 and 116 in 2004.

— Yes, the first experiments began just as the new century began – in 2000. Our accelerators have been operating with the calcium-48 ion beam around the clock, almost non-stop, with no holidays, no weekends for about 100,000 hours. Because the synthesis of a new element is a very rare event. We were happy when we got one atom a day. By 2012, all the superheavy elements known today had already been synthesised. At some point, it became a matter of technique.

— Will the 119th and 120th elements also be inhabitants of this stability island? Will we be able to hoist the flag there too?

— Absolutely. This is all one land. In ten years, we have managed to explore this island, to see that it really is there. In theory, it includes many elements.

— Why is it believed that the Mendeleev’s Table can expand to the 172nd element, what is the reason for this limit?

— We could talk about this if we were sure that a nucleus with such a huge positive charge could exist. When the first steps towards superheavy elements were taken, the possible existence of an atomic nucleus with 114 protons was discussed. The existence of an island is determined by the properties of nuclear matter, not by the electronic structure of the atom. But will there be a second island that will provide the opportunity to advance significantly further in the synthesis of elements? It seems to me that the limit of the existence of nuclei will occur much earlier than 172.

Creation of the world. Made in Russia

— We walked around the concrete box that will house Russia’s new NICA collider, which scientists say will reproduce the beginning of the world… Can we go into more detail from this point?

— Let’s start from afar. In the first moments after the Big Bang, a hot plasma composed of quarks and gluons emerged. By the way, gluon is for “glue” in English, which means it is the substance that glues quarks together. Roughly speaking, about a microsecond after the Big Bang, the universe was a gluon soup in which quarks were floating (physicists call the matter in this state quark-gluon plasma). And then, when the temperature dropped, the quarks were combined in a certain way into protons and neutrons with the help of gluons. Then protons and neutrons into nuclei. Further cooling led to the construction of electronic structures around the nuclei. The formation of atoms (elements) was going on. This is the creation of the world.

— When did this happen?

— A very long time ago. One microsecond after the Big Bang. What do we want to do now? Go back, melt protons and neutrons into quark-gluon plasma and see the creation of protons and neutrons – the building blocks of the universe.

— Is it physically possible? What does it take?

— It takes enormous energies to melt protons and neutrons back into the soup. To do this, physicists accelerate two heavy nuclei, such as gold or lead, to high energies and collide with each other. At the point of frontal collision, the temperature rises to a record one trillion degrees and then some of the protons and neutrons are transformed into quarks and gluons for a moment. And then instantly goes back.

— Is it enough of a moment to know something?

— Yes, that’s quite enough. But such a quark-gluon plasma has not been produced in its pure form yet, although attempts have been made – in a variety of ways. There was not enough impact energy. So we moved towards higher and higher energies. At CERN, for example, there have already been several generations of accelerators capable of accelerating sufficiently heavy particles to see this effect in a collision. It is possible that very high energies are not so effective because the maximum heating of the collision zone is determined by the nuclear stopping power, which is maximal in a certain energy range. And perhaps the lack of effect in previous experiments is due to the excessive collision energy of the nuclei. The NICA parameters are chosen taking this into account.

— Isn’t it too expensive to build a machine for one particular experiment? Today, when nuclear physics equipment is very expensive, there is a great risk of making a mistake and putting it on the wrong project.

— Right question. Although it begs the question: “too expensive” compared to what? But from my point of view (I’m not imposing it), the opposite is wrong – building machines for all occasions. Because when there are many goals, there is a great risk of not achieving any. In addition, construction, precisely because it is large and expensive, will take time, and the facility may become obsolete before it is completed. On the contrary, in the case of a specific task, everything is focused on the goal.

— What happens to such a single-tasking technique afterwards?

— I don’t really understand what a single-tasking technique is. This is a scientific study. You have to achieve what you want to see (equip the experiment with more and more new technology in the process). And if it doesn’t work, we need to understand why it doesn’t work the way the theory predicts. At the beginning of the interview we talked about the superheavy elements. The world’s largest nuclear physics laboratories worked on this problem for 50 years before they were synthesised and their properties confirmed theoretical expectations.

— The Superheavy Element Factory and NICA are purely Basic Science. How do you explain to officials why they need to spend such enormous resources on it?

— No need to explain anything to anyone. I recently performed at St Petersburg University, to a large audience of people of different specialities. Accordingly, there were different questions. One of the people present, a man of advanced years, asks in a tragic voice: okay, so you discovered the superheavy elements, filled in the seventh period of the Mendeleev’s Table and what has changed because of that? I say: nothing at all, you can sleep in peace and go about your business.

— It is often said that the superheavy elements will form the basis of a new energetics, as a few milligrams of any of the substances discovered are equivalent to 20 kg of uranium. Don’t you think that would be convincing?

— To understand the significance of such works is not really easy, some preparation is needed. You have to know the particularities of scientific work, a perpetual search, a lot of trial and error, before you have the inner certainty that you are finally on the right track. But that’s not the result either. You’ll have to go through thick and thin to get it! We have to make a device that does not exist in the world, obtain a super-pure substance that nobody knows how to obtain, there are no recipes or analogues, create a detector that does not sense a background that is a thousand times higher than expected, and so on and so forth… We have to put everything aside and do something that nobody has ever done before.

You go where there is no road because nobody has gone there before. So a lot of purely scientific and technical problems have to be solved, and these solutions often become know-how. They are priceless! From the outside, it looks like a ship under the flag of science, sailing to its fundamental home port.

She pulls a net with all kinds of fish in it, some of which are not golden but priceless. This is the way, they say, the Internet came into being: physicists didn’t know how to deal with masses of information, so they came up with local networks.

Another important factor is the attractiveness of the science profession to bright young people. Then they reach for knowledge, go to the forefront of science and, in effect, advance scientific and technological progress. Remember how recently there was a lot of talk about the discovery of the Higgs boson at CERN? This was done at the accelerator complex, the Large Hadron Collider (LHC), the bearer of all modern accelerator technology. The cost of the installation is said to be more than €9 billion.

Don’t you think that one day the heads of the CERN Member States (and CERN’s budget is the contribution of the Member States and Associate Members, mostly from Europe and the USA) got together in Geneva and thought: why don’t we contribute an additional 9-10 billion to confirm the existence of the Higgs boson? And they did. And confirmed!

I believe they did intend to, and certainly approved of the idea of the LHC. That is, the flag was right, the Higgs boson, and the LHC, I think, paid for itself. But the main idea was that high-level specialists would do it, and the younger generation, looking up to them, would go there too. Skilled, gifted people are needed everywhere: in politics, the arts, business, mathematics, sport, literature, aircraft engineering. But talented young people on the frontline of scientific and technological progress are the breakthrough of society, they are the future of the country and its people. I was once told, do you know what it’s worth going to the CERN canteen for? About 1,000 of these young people gather there at lunchtime at the same time, chatting, laughing, gesticulating! And this is truly impressive…

— You are hard to find in Russia these days. So why didn’t you go to work abroad in the 1990s when everything was falling apart?

— There have been more than one offer, but somehow it doesn’t work out for me. I worked in France, but left it early, for which I was reprimanded here. Twenty years later, my former French colleagues invited me over one day and said, “Do you remember what you said when you left? You said you were more excited to be there.” I realised that they still couldn’t forgive me. But I was really much more interested in Russia. In general, when we say that many people have left, we have to understand that most of them have been forced to do so. They had no choice, going far from the top positions. I also have an example in my family – my daughter’s husband, a young physicist, an excellent experimenter, worked at LPI, they built a telescope on Tian Shan to study cosmic rays. So interesting that the Americans wanted to send their trainees to him because they wanted to build one in Peru. He worked passionately and gave five years to the project, living half time in Moscow and the other half on the mountain. And then suddenly it turned out that there was no Soviet government, and Kazakhstan did not need this telescope. It was a difficult time, and then one of his friends encouraged him to go to graduate school in the United States. Imagine what it would be like for someone who has already completed postgraduate studies and built a telescope to find himself back at his desk with the newcomers? In general, when I organise conferences both here and in the West, I make sure to invite all these people who have left to speak, to communicate, to hear. This is very important for us and for them.

— As far as I know, you wanted to be an architect? What were you going to build?

— Nothing meaningful, in that direction, was on my mind. My father was a communications engineer. Architects, engineers, and other housing specialists gathered at home. In my father’s working group there was a young man, Yuri Yaralov, who later became a famous architect in Moscow. He told me I had certain abilities and helped me take my first steps in architecture. I took exams at MArchI, but before that, as a medallist, I had an interview at MEPhI in Moscow with some friends. Eventually, when I wanted to take the documents to MArchI, they wouldn’t give them back to me at MEPhI. They said I had already been enrolled.

— Who studied with you?

— I entered in 1950 and got into a very interesting community. It consisted of two categories: us 17-year-olds and the people who came from the front. They were about ten years older: after the war, many quickly realised they had to get an education. We studied together, we lived in the dormitory, but we always treated our elders with great respect, and they never reprimanded us either.

— Everybody probably dreamt of doing nuclear physics then, because it was just in 1949 that the USSR tested its first nuclear bomb – four years after the Americans dropped bombs on Hiroshima and Nagasaki.

— The topic was very popular and semi-closed, everyone knew that the government was investing huge amounts of money there. We were taught two programmes, given courses by the Physics Department of MSU and from Bauman University, clearly with an engineering focus. At the end, we took ten exams every term! However, there was no unified, established programme. But everyone understood: we were being trained as specialists in nuclear energy. Back then, everyone, not just scientists, but also people in government, felt that we were standing on the threshold of some new era. Roughly speaking, man was able to get the energy from uranium that was put there at the creation of the world. So I knew I was going to do nuclear physics, but until the last moment I didn’t know exactly where I would be assigned.

— Where did you want to go?

— I got married at that time. My wife was a violinist and was admitted to the Moscow Conservatory for postgraduate studies in violin. This caused some inconvenience because all our major nuclear facilities were located far from the capital. So I wanted to stay in Moscow. I came to the Institute of Atomic Energy, which was led by Igor Kurchatov. I was interviewed first by Andrey Budker and then by Georgy Nikolaevich Flerov. That’s when I met the people I later worked for. Andrey Mikhailovich Budker gave me an hour-long examination. He was pleased and was going to hire me, but then it turned out that he didn’t have any places. He caused a scandal in the human resources office, the personnel staff was very unsatisfied. I was told that another person was coming to talk to me. Flerov was interested in what I was into, what sports I played. That’s all. That’s how I ended up in his laboratory. And then my biography is simple: I was assigned to the Joint Institute for Nuclear Research in Dubna when it was formed. I have lived and worked here ever since. It’s been 60 years now.

— Academician Flerov worked on the creation of the atomic bomb, and the institute was set up, as I understand it, as a kind of international collaboration for the study of the peaceful atom. How did it come together?

— As long as atomic energy was linked to the bomb, it naturally had its limitations in terms of secrecy. So it was both in the USSR and States. But when the first NPP was built in Obninsk (that was in 1959), everything started to be perceived differently. It became clear: nuclear power is not just an explosion, it is controlled power. It seems to me that the taming of atomic energy has provided a real boost to nuclear physics. Both peaceful and military, which after the atomic bomb took up the hydrogen bomb.

Ogoniok and Skoltech special project on the most advanced achievements in physics

— What do you think of the opinion that Soviet physicists borrowed the atomic bomb project from the Americans?

— This is absolutely not true, and I don’t understand why this opinion is being so widely publicised. In 1989, there was a large international conference in the USA to commemorate the 50th anniversary of the discovery of uranium fission. It was very interesting because it was the first time that physicists from different countries who had previously only known each other through publications had met. Georgy Nikolayevich Flerov gave an excellent report there, which showed what an amazing flourishing of physics there was in our country before the war. It was impressive! Just look at the amazing schools of Abram Fedorovich Ioffe in Leningrad and LPI in Moscow!

— Why, then, did the Americans build the bomb first?

— Because it’s not just knowledge and understanding of specific principles that are important here, but also performance. Uranium extraction, separation, and enrichment require a huge infrastructure. Dozens of plants had to be built. And World War II was raging in our country! But to think that after the war one could look up and do all this extensive work in four years is naive. It is now known that each team of scientists followed its own path, and if any information was leaked, it could not have been decisive in solving the enormous task.

— Do you have time for anything other than work? Read, see, go somewhere?

— Nine years ago my wife died and my children moved away, so I am the master of my own time. I have to travel a lot for work, but when I visit my daughter in America, I like to go to theatres on Broadway. I love this form of theatre, which is completely modern and employs high-class artists with amazing voices! I also really like the Japanese Kabuki theatre. This is fantastic! Their stage movement, speech, facial expressions, incredible costumes, and voices are amazing. Done very professionally and talented, which is what I appreciate in everything.

Author is Elena Kudryavtseva,
Source: Kommersant | Ogoniok