Search

Experimental works performed on the Dubna gas-filled magnetic recoil separator (GFS) to study the reactions of formation of 294Ts and 294Og nuclides and the properties of their radioactive decay are described. Future possibilities of synthesizing new elements with Z = 119 and Z = 120 and performing experiments to study the properties of heavier isotopes of known superheavy nuclei Lv (Z = 116), Ts (Z = 117), and Og (Z = 118) are discussed.

The search for new decay chains of oganesson isotopes is presented. The experiment utilized the Dubna Gas Filled Recoil Separator and a highly segmented recoil-decay detection system. The signals from all detectors were analyzed in parallel by digital and analog data acquisition systems. For the first time, a target of mixed californium (51% Cf249, 13% Cf250, and 36% Cf251) recovered from decayed Cf252 sources was produced and irradiated with an intense Ca48 beam. The observation of a new decay chain of Og294 is reported. The prospects for reaching new isotopes Og295,296 are discussed.

The decay of 218Pa was investigated by means of α and γ spectroscopy. The nucleus was produced in the fusion reaction 40Ar+182W and separated in flight by the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). The known α decays of 218Pa were measured with improved precision and newly assigned to be originating from the ground state, which clarified the ambiguities in their previous assignments. In addition, a new isomeric state in 218Pa decaying with α-particle energies of 9691(15) keV, 9595(21) keV and a half-life of 135−32+62 μs was identified. The spins and parities of the involved states were tentatively assigned on the basis of the systematic α-decay properties of the odd-proton N=127 isotones and shell model calculations. Keywords: Odd-proton N=127 isotones, Isomeric state, α-particle energy, Half-life, Shell model calculation, Spin and parity