Determination of α preformation for heavy nuclei

The α preformation factor and the penetration probability have been analyzed for heavy even-even nuclei in the frame of double folding model using the experimental released energies and α decay half-lives. The α preformation factors are compared with Po, Rn, Ra isotopes as well as Cm, Cf, Fm, No, Rf isotopes, respectively. It is shown that the α preformation factor is variable and the shell effects play an important role in the α preformation. The closer the nucleon number to magic number, the more difficult the α formation in the parent nucleus is. The preformation factor can supply the information of nuclear structure and the penetration probability determines mainly α decay half-life.