Heavy-element research at FLNR (JINR)

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Bulletin of the American Physical Society

OSTI ID:255524

Oganessian, Yu Ts

Results of research on the synthesis and investigation of properties of heavy nuclei in the bottom of the Periodic chart of elements carried out by the FLNR (Dubna) - LLNL (Livermore) collaboration are presented. These results have led to the observation of a new region of nuclear stability near the closed deformed shells Z=108, N=162 predicted by the macro-microscopic theory. The research has been carried out at the FLNR (JINR) with beams from the U=400 heavy ion accelerator using the Dubna gas-filled separator of recoils. The heaviest isotopes Z=104, 106, 108 and 110 have been synthesized in hot fusion reactions of {sup 238}U, {sup 244}Pu and {sup 248}Cm nuclei with ions of {sup 22}Ne and {sup 34}S. Their radioactive properties point to a substantial increase of stability with respect to spontaneous fission in the whole known region of nuclei of transfermium elements with N=158. The vartial half-life for the {sup 262}104 nucleus with respect to spontaneous fission has been experimentally determined: T{sub sf}=1.2{sub 0.5}{sup +1.0} s. All other isotopes with Z{ge}106 undergo mostly the {alpha}-decay. The experimental systematics of the {alpha}-decay energies Qa(N) for all the known isotopes with Z=98-110 determines the status and strength of structural effects near closed deformed neutron shells N=152 and N=102. It is demonstrated that the calculated values of nuclei near shells N=162 are in a good agreement with the experiment. The discovery of a new region of nuclei stability near closed deformed shells allows to make more accurate assessments regarding the properties of heavier nuclides up to Z=120 and N=190. For them a much stronger effect from spherical shells Z--l 14 and N=180-184 is predicted, which opens a possibility of further progress into the region of superheavy elements. The prospects of making superheavy nuclei and the advantages of using different types of fusion reactions are discussed.

• OSTI ID: 255524
• Report Number(s): CONF-9510116--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 10 Vol. 40; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
CALCIUM 48 REACTIONS
HALF-LIFE
ISOTOPE PRODUCTION
PLUTONIUM 244 TARGET
TRANS 104 ELEMENTS