Fine Structure Of Alpha Decay In Pa-222

With the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system, the fine structure of the alpha decay for Pa-222 was studied. The nuclides were produced through the 1p3n evaporation channel via the heavy-ion induced fusion evaporation reaction Ar-40 + W-186. Based on the ER-alpha 1-alpha 2-alpha 3 and alpha-gamma correlation measurement, three new alpha decays were observed in addition to the three branches known previously. The one with the largest alpha decay energy was regarded as the ground state to ground state transition. The newly measured alpha decay properties of Pa-222 were examined in a framework of reduced width.