“Everything will become obsolete in fifteen years”

Russia’s Nobel Prize nominee, Yuri Oganessian, on the search for the next chemical element at the new accelerator in Dubna

Employees of the Joint Institute for Nuclear Research are ready to launch the first run of the SHE Factory, a scientific facility unique by global standards for the synthesis of new superheavy chemical elements and research on recently discovered elements. The centrepiece of the Factory is the DC-280 cyclotron accelerator of charged particles. RAS Academician, Scientific Leader of the Flerov Laboratory of Nuclear Reactions, Yuri Oganessian told Izvestia about the purpose of the Factory, about the first two experiments with the new equipment, as well as about the mysteries of new chemical elements.

— Yuri Tsolakovich, the last element in the Mendeleev Table is now the 118th. Theoretically, 172 elements are known to be predicted. So how many can there really be?

— How many elements there can be is a worrying question, and it must be answered. The old classical theory predicted 100. Now there is already a 118th. I can tell you that this is not the maximum, we can move on.

We see the material world as a continent of stable elements that spreads to lead. Then there is a narrow isthmus of short-lived elements to radium, followed by natural uranium, thorium, and long-lived transuranic elements to californium. It is like a peninsula. Then there are islands far away from the known element area: one, perhaps two, or even three. This is how the world is organized, according to the new theory, because nuclear matter has an internal structure.

— Was the hypothesis of the existence of “islands” accepted at once?

— At first, it seemed almost insane. Then we got used to it, began to discuss it vigorously, believed it. Experimental groups from many of the world’s major laboratories rushed to look for superheavy elements in terrestrial and lunar samples, in space and in the products of nuclear explosions. Five underground nuclear explosions were done in the USA. Experiments have been carried out at powerful heavy ion accelerators. Unfortunately, all attempts to find hypothetical superheavy elements in nature or artificially synthesise them have been unsuccessful.

— How many years did it last?

— We were looking for superheavy elements for fifteen years. Then, as it usually happened, a period of pessimism started. If you look for something but do not find it, there are two reasons: either you did not reach it, or it does not exist. However, when different people search for it in different places, at different facilities and do not find, the second reason begins to prevail over the first. We did not share this opinion, continuing to search hard for these islands.

Scientific search is not only weird thing, but also an exhausting one. It is like you’re walking along a path in a labyrinth and then see a dead end. You have to come back and take a different path. There is a dead end again, and you go back again. You need to be patient to continue this weird activity for many years. They say that if there is seven successful attempts out of a hundred, it is genius.

— You knew this would happen when you became a scientist, didn’t you?

— No, as many other young people, of course, I did not. I became a physicist by accident in some sense. Firstly, I wanted to become an artist, an architect. Together with other medallists, I came to enter in Moscow universities. Even medallists take specialised exams there, in my first case, physics and mathematics. I gave my documents to MEPhI of those years, passed these two exams quite easily. Then I went to MARKHI. The specialised exams, painting and drawing, were obligatory for everyone. I really enjoyed the democratic approach in architecture university. Anyone from the street could come and take an exam. I passed it with flying colours too. They said, “Bring your documents. You don’t need to take other exams as you’re the medallist.” I came back to MEPhI. They answered, “Your documents are currently under consideration getting admission to official documents. Come back in three months, not less.” Therefore, that is how I got into nuclear physics.

— Returning to the search for superheavy elements, why did you continue the search?

— Arguments in favour of the fact that this does not exist were less tenable than the prediction that superheavy elements can exist.

— How did it happen, that the whole world was looking for it, and it were you who found it?

— We realised that in all previous cases, including our first attempts, something was wrong. There was something missing in the arrangement of the experiments, not only the technical questions remained open Sometimes the starting positions on which a particular approach of solving tasks was based, were far from being perfect. Moreover, if we looked for another solution, then there was no other way out than to complicate the experiment greatly.

— And when did you understand that this strategy would work?

— Only in 2000. When we received first two atoms of 114th element. However, after fifteen years we synthesised all other elements up to 118th in the same way.

— What do you know about 118th element, oganesson, which you personally discovered and which is named after you?

— Not much yet. The first thing is that this, currently the heaviest, element really exists. That its nucleus in a thousandth of a second spontaneously passes into the nucleus of the 116th element, which, in turn, into the 114th element, that one into the 112th, the last one is divided into two fragments. We knew this radioactive family, originating from the 118th element, from previous experiments.

The 118th element has a place in the last group of noble gases in the Mendeleev Table. It closes the seventh row of the periodic table. To what extent it will exhibit the properties of a noble gas, we have not known yet.

— Do you have any ideas how to find that?

— We need to come up with an experiment that could answer this question. The first group of the Mendeleev Table includes the most chemically active elements, while the last one includes chemically inert elements. Noble gases are inert, they do not compound. Another intriguing moment is the leap from the 118th to the 119th element. There will be a huge difference between them, since it is the leap from the most inert to the most active element. Will this difference really be giant? To answer this question, we need to get 119th element and see this difference.

— Do you need a new accelerator?

— Yes, we need to get much more atoms of superheavy elements. Previously, we considered it great when we received one atom a day. Now we will need to get a hundred times more! In general, there will be another life. Once again…

— Do you need other speeds, other targets?

— We need more target material. What we have now is obviously not enough. A new factory is needed for these and many other investigations. Because everything we had and have now, despite all our world records, is not suitable for such tasks. We need to abandon the old with no regret and start doing it again. That is how we did: since 2012, we have started to build, in fact, a new laboratory of superheavy elements.

— When did the idea to build a factory arise?

— When we finally succeeded. Obviously, there arose a question: what is next? When we need to make a difficult, for example, strategic decision, we gather in the empty office of Georgy Nikolaevich Flerov, in our small museum (his former office) and discuss a problem there to find ways to solve it.

During one of such gatherings, I told that to continue search we needed to answer one question. It took us fifteen years of practical round-the-clock work to discover all superheavy elements. But what if we had started this work not in 2000, but in 2015, how long would it have taken us?

It turned out that in fifteen years all our work could have been done a hundred times faster! But then it follows that we should throw away all our property, accumulated over the years and led us to the discovery of new elements, and build a new one corresponding to the reality. Now, creating a new accelerator, a new separator, and detectors we must always feel the time. Everything will become obsolete in fifteen years!

— What is the first experiment planned on the new accelerator

— The first experiment or, more precisely, the first two experiments, each of which will last 50 days, will be demonstration. We must show to everyone and ourselves first that the ideas underlying the scientific and experimental complex we have created are rational. Experiments of the synthesis of 114th and 115th elements will be repeated. Previously, we observed just piece quantity of atoms. Now there should be several hundred. As for the first launch of the accelerator, we will have two of them: one of them is physical, another one is chemical. Physical launch of the complex will be performed based on the results of the first experiment. Then the inauguration of another complex will take place. Then a new life will follow according to the scientific programme designed for fifteen years.

Source: Izvestia magazine