On 30 June – 2 July, a meeting “Superheavy elements” took place in Dubna. The aim of the event was to discuss the programme of superheavy elements research and development of the infrastructure for its implementation. RAS President A. Sergeev took part in the meeting.

A. Sergeev proposed considering the concept of establishing a large laser complex in Dubna to develop these technologies in Russia. He also highlighted the importance of the international status of the Joint Institute for Nuclear Research. “It is a special pleasure for me to visit Dubna. JINR is the only international scientific centre in our country. It was founded at the height of the first phase of the nuclear arms race. The superpowers have recognized that international scientific organizations contribute to cooperation in the framework of peaceful nuclear research. Though the situation in the world is rather tense, sustainable scientific cooperation is of the highest priority. There should not be isolation and xenophobia. The role of Dubna, as a centre basing on international cooperation and developing it, is significant for Russia. I hope that the NICA complex will be launched as scheduled. It will be a great event for our country,” RAS President said.

Academician A. Sergeev presented a report “Ionization of vacuum by extreme light fields”.

The event was held under the auspices of the RAS Council on Heavy Ions. It gathered about 200 participants from Russian and foreign scientific centres, including those from Germany, Switzerland, Israel, and the USA, both offline in the International Conference Hall in Dubna and in the online format.

Director of the Joint Institute RAS Academician G. Trubnikov highlighted the importance of discussions of the progress in the implementation of the project on the study of stability borders of nuclear matter. “This project has been selected within the support programme for large-scale scientific and research projects organized by the Russian government. The Russian Academy of Sciences coordinates this project,” G. Trubnikov said.

The Institute’s Director found it an important part of the meeting to discuss the development of this research field up to 2030 and further. “Promising research fields provide the basis for new programmes being discussed nowadays at JINR, the Rosatom State Corporation, and many other RAS organizations,” Grigory Trubnikov noted.

Research in the fields of heavy-ion physics and superheavy element synthesis connect different scientific directions. This includes new generations of computing algorithms, material sciences, applied fields of sciences related to UHF devices of new frequency range and capacities.

The JINR Director also spoke about the current Seven-Year Plan of JINR Development (up to 2023), in particular, about its five flagship projects: the NICA facility, the Superheavy Element Factory, the IBR-2 reactor, the Baikal neutrino telescope, and the Multifunctional Information and Computing Complex.

“The key advantage of JINR is unique large-scale experimental facilities,” G. Trubnikov noted.“Today the Institute is focused on innovative research. The project involves the creation of an interlaboratory research centre, i.e., establishment of new large facilities in different laboratories operating according to complementary logic. This also includes a new-generation superconducting setup for radiobiological and neurobiological research, created jointly with FMBA and the Ministry of Health of the Russian Federation. The implementation of the project will take about three years.”

The development strategy of JINR comprises mainly new research facilities. By 2035-2036, the Institute plans to launch a new pulsed reactor with neptunium fuel, which will replace the IBR-2 reactor.

At the beginning of the year, successful experiments on the synthesis of element 115 (moscovium) were carried out at the Superheavy Element Factory. “The Factory has been going up in terms of productivity for three months. We have to be very careful: to protect the target, we walk in small steps. We started with 1 µA, then 1.2, 1.5, 2 and 3 µA. Here we stopped: what the Factory gives today is ten times more than before it. And we want even more,” said Yu. Oganessian, Scientific Leader of the Flerov Laboratory of Nuclear Reactions. Now the Factory is getting ready for the new stages: experiments to clarify its limits and preparations for the synthesis of elements 119 and 120.

The programme of the first day of the meeting included reports by JINR leading scientists and specialists as well as their colleagues from Russian scientific centres and Darmstadt (Germany). V. Shabaev (SPBU) presented a report “Vacuum decay and its observation in the collisions of heavy nuclei”; V. Utyonkov and A. Karpov (JINR) made the report “Flerovium (Z = 114) and moscovium (Z = 115) at the SHE Factory. Transition to the synthesis of elements Z > 118”.

M. Yavor (IAI RAS) spoke about the spectrometer for precision measurement of the masses of superheavy atoms. M. Itkis (JINR) presented a report “Quasi-fission as the first “traffic light” on the way of superheavy elements production”. V. Tupitsyn (SPBU) reviewed the calculations of physical and chemical properties of the elements of the seventh period and their homologues.

In continuation of the report by V. Pershina (GSI, Darmstadt) on the chemical behaviour of superheavy elements in gas-phase experiments, JINR Vice-Director S. Dmitriev noted that “relativistic effects force us to look very closely at these elements”. He spoke about joint work with the group of Dr. R. Eichler from PSI (Paul Scherrer Institute, Switzerland) and the success of the scientific community in the attempt to answer the question whether “superheavy elements are close in properties to inert gases (i.e., can they be called “volatile metals”)”. The speaker concluded that when working with short-lived isotopes, the methods of gas chemistry have significant advantages over the “water” ones. The first experiments in this field allowed discovering that element 112 in terms of adsorption is analogous to mercury (therefore, copernicium is also called eka-mercury) and refuted the theory that flerovium is more chemically active than copernicium.

Then the speaker went on to describe the scheduled experiments. At the Superheavy Element Factory, where the participants went on excursion, the final adjustment of the DGFRS-3 facility is underway. With this separator experiments on the chemistry of flerovium and copernicium will be performed. The improved version of DGFRS, like DGFRS-2, includes a thermalisation chamber instead of detectors. Another advantage is that the response time of the facility technique is less than 1 s.

D. Soloviev (JINR) devoted his report to the GASSOL separator and its application in chemical experiments.

Scientific Leader of the ART-XC telescope named after M. N. Pavlinsky RAS Professor A. Lutovinov spoke about the results of the Spektr-RG project. The Space X-ray Observatory was launched in 2019. “The scale we work with is 70 times larger than the superheavy elements you search for. But physics is the same,” Professor Lutovinov noted. “The main source of X-ray radiation is supermassive black holes, galaxy clusters, the interstellar medium and accreting neutron stars. All these sources are marked on the map obtained after the Spektr-RG survey. One of the objectives of the observatory is to detect large clusters of galaxies. It is believed that there are about 100,000 large galaxy clusters in the Universe. Spektr-RG will see them all.”

The first part of the programme of the second day of the meeting included reports from FLNR JINR staff members: G. Adamyan (“Synthesis of the heaviest nuclei in the fusion reactions of ⁴⁸Ca, ⁵⁰Ti, and ⁵⁴Cr nuclei with actinide isotope nuclei”); A. Karpov and V. Saiko (“Synthesis of neutron-rich nuclei in the vicinity of closed neutron shells N = 126, 152, and 162”); G. Knyazheva (“Experiments to determine the yield of heavy fragments in the reactions ²³⁸U + ²³⁸U and ²³⁸U + ²⁴⁸Cm”); I. Kalagin (“Accelerators of FLNR JINR for producing beams of stable and radioactive ions”); S. Bogomolov (“ECR-28 GHz source for the production of high-intensity beams of heavy ions up to ²³⁸U. Expected results”).

The programme of the second session included reports on the research performed at the Russian scientific centres: “Production of target materials – ²⁴⁸Сm, ²⁴⁹Bk and ²⁵¹Cf isotopes at SM-3 reactor” presented by A. Tuzov (RIAR); “Electromagnetic separator for isotope enrichment of heavy actinides” by V. Zavyalov (VNIIEF), “High-current ECR ion sources of highly charged ions and modern systems of plasma heating” by V. Skalyga (IAP RAS), “Development of superconducting magnetic system for ECR source” by I. Rodin (NIIEFA).

During the third day of the meeting, participants discussed the flagship project of JINR the NICA heavy-ion collider. As JINR Vice-Director V. Kekelidze said in his report on the status of the NICA collider construction, the main goal of 2021 is the integration of the Booster into the general system of the accelerator complex. The first experiment at the collider is scheduled for the end of 2021, the Year of Science and Technology in the Russian Federation. “We plan to demonstrate the whole cycle of the beam injection, its acceleration and transfer to the research facility,” V. Kekelidze noted. “At the first stage, the channel for the beam transfer from the Booster to the Nuclotron will be mounted (by specialists from Novosibirsk). In the near future, the assembly of the MPD (Multi-Purpose Detector) – one of the key elements of the collider complex at JINR – is expected.”

The basic elements of the JINR megascience project were presented in the reports by D. Dementiev (“Baryonic matter at Nuclotron”), V. Kireeu (“Multi-Purpose detector for the NICA collider”), and A. Guskov (“Spin physics detector (SPD) for the NICA collider”). Participants had an excursion to the construction site of the accelerator complex at VBLHEP JINR.

E. Molchanov, JINR Weekly Newspaper;
Materials by science portal “Scientific Russia” used;
photos by E. Puzynina