Fine structure in the alpha decays of U-226 and Pu-230

The nuclei U-226 and Pu-230 have been populated via reactions involving Pb- 208 targets bombarded by Ne-22 and Mg-26 projectiles. Fusion-evaporation re sidues were separated in-flight using a gas-filled recoil separator. A posi tion-sensitive Si-strip detector was employed at the focal plane in order t o identify correlated alpha-decay chains. Two fine structure alpha-decay li nes have been observed. The first, with an energy of Th-222. The second lin e, 7385(5) keV, is assigned as the alpha decay from U-226 to the first exci ted 2(+) state of observed for the first time in this work, has an energy o f 6961(30) keV and is assigned as the alpha decay from Pu-230 to the first excited 2(+) state of U-226. The excitation energy of the first excited 2() state in U-226 was determined to be 96(25) keV, giving an estimate of the deformation parameter beta(2) similar or equal to 0.20.