Measurement of evaporation residue cross-sections of the reaction 30Si + 238U at subbarrier energies
- 165 Downloads
The reaction 30Si + 238U → 268Sg* was studied at beam energies close to the Coulomb barrier. At a center-of-mass energy of E c.m. = 144.0MeV for reactions at half thickness of the target we measured three decay chains of 263Sg produced by evaporation of five neutrons. The cross-section was ( 67+67 -37) pb. At E c.m. = 133.0MeV we measured three spontaneously fissioning nuclei which we assigned to the isotope 264Sg. The production cross-section was ( 10+10 -6) pb and a half-life of ( 120+126 -44) ms was determined. This half-life is a factor of twenty shorter than theoretical predictions. At E c.m. = 128.0MeV an upper cross-section limit of 15pb was measured. The cross-section data reveal a strong influence of the orientation of the deformed target nucleus on the production yield. Compared to excitation functions measured for the lighter system 16O + 238U → 254Fm*, a reduction of the fusion probability was observed at low beam energies indicating increasing competition from quasifission processes.
PACS.25.60.Pj Fusion reactions 23.60.+e α decay 25.85.Ca Spontaneous fission 27.90.+b 220 ⩽ A
Unable to display preview. Download preview PDF.
- 6.K.E. Gregorich, private communication (2006).Google Scholar
- 15.R. Mann, GSI Scientific Report 2003, 224 (2004).Google Scholar
- 16.E.K. Hulet, Phys. At. Nucl. 57, 1099 (1994).Google Scholar
- 17.P. Cagarda, PhD Thesis, Comenius University, Bratislava (2002).Google Scholar
- 20.S. Hofmann, J. Nucl. Radiochem. Sci. 4, R1 (2003).Google Scholar
- 24.R.B. Firestone, V.S. Shirley (Editors), Table of Isotopes, Vols. 1 and 2, eighth edition (John Wiley and Sons, Inc., New York, 1996).Google Scholar
- 30.J. Dvorak, GSI Scientific Report 2004Google Scholar
- 31.K. Nishio, unpublished.Google Scholar
- 32.K. Hagino, unpublished.Google Scholar