Yu.Ts. Oganesyan

Experiments on the synthesis of neutron-deficient isotopes of kurchatovium in reactions with accelerated50Ti ions

ConclusionsA number of conclusions can be drawn from the aggregate of experimental results.The method of synthesis of transfermium elements in the irradiation of lead isotopes with ions with mass AI≥40 atomic units, investigated earlier [12] for the example of the reaction Pb(40Ar, xn)Fm, is also extremely effective using50Ti ions. The reactions Pb(40Ar, 2n)Fm and Pb(50Ti, 2n)Ku have approximately equal cross sections, which might have been expected on the basis of theoretical estimates. This permits us to hope that this method can be used successfully for the synthesis of heavier elements in the reactions induced by54Cr,55Mn, and58Fe ions.In all probability, the substantial changes in the systematics of the half-lives for even-even isotopes of kurchatovium are associated with the structure of the barriers to fission of these nuclei. From this standpoint, it seems important to investigate the properties of more neutron-deficient isotopes of kurchatovium, using, in particular, the reactions with204Pb, and to attempt to advance into the region of elements with Z≥ 106. On the other hand, a detailed theoretical analysis must be made of the data obtained on the basis of the modern theory of nuclear fission, which, in our opinion, will aid in a more reliable prediction of the properties of heavy and ultraheavy elements.

Design of the JINR four-meter isochronous cyclotron with smoothly regulated heavy-ion energies

Further development in the physics of nuclear reactions between complex nuclei is bound up with the use of fast ion beams of even heavier elements in these reactions and also with an increase in their energy and intensity. For this purpose, a four-meter isoehronous cyclotron (accelerator U-400) has been designed in the JINR Laboratory of Nuclear Reactions on the basis of the results obtained in the construction of the JINR two-meter isoehronous cyclotron U-200 [1]. At the present time, work at JINR involves the fabrication of parts and sections of the U-400 accelerator, which is being built on the foundations of the existing 310-centimeter, classical heavy-ton cyclotron (accelerator U-300) [2]. The parameters of these accelerators are given in Table 1, from which it is apparent that practically all the systems of the U-400 accelerator differ significantly from those of the U-300. The U-400 cyclotron is vei:y much like the U-200 accelerator, which can be considered as a model of the larger accelerator on