| Popis: |
Experimental and theoretical data on the production of the neutron-deficient isotopes 244 Fm and 246 Fm in the bombardment of lead and bismuth isotopes with 40 Ar and 37 C1 ions are presented. By using different lead isotopes, the cross sections for the ( 40 Ar, x n) reactions with x = 1, 2, 3 and 4 have been measured. It is shown that when a target of the “magic” 208 Pb nucleus or its neighbours is bombarded with ions of mass $ = 40 , the compound nuclei formed appear to be weakly excited and to de-excite by emitting only 2 or 3 neutrons. New possibilities of synthesizing elements with atomic number Z > 100 are being discussed in the framework of the experimental data obtained. |
