Excitation function for the production of 265108 and 266109

Abstract

The excitation function for the production of266109 by the reaction 58Fe + 209Bi was investigated. Its position and width could be reproduced using the same values (E* = 13.9 MeV; FWHM=4.8 MeV) as inthe case of265108 produced by the reaction 58Fe + 208Pb. A cross-section maximum of (7.5 ± 2.7) pb was obtained. Referred to 265108, this value is reduced by a factor of 8.8 ± 3.3, that is more than the average reduction of cross-section by 3.7 per element. The hindrance factor of 2.4 ± 0.9 could be due to a specialization energy in the fusion process by the unpaired proton of 209Bi in the h9/2 orbital. A total of twelve decay chains of 266109 was measured, resulting in a mean half-life of (1.7−0.4+0.6) ms. The new data confirm the decay data of the previously measured two decays of 266109.