α-cluster preformation coefficients and level densities from natural α radioactivity and (p, α) reactions

Abstract
It is shown that an alpha -cluster preformation coefficient and an alpha -cluster level density can be calculated for nuclei or a pair of neighbouring nuclei for which the alpha radioactivity and (p, alpha ) reaction are measured. The analysis of these two kinds of alpha emission is made on a similar basis by applying the ideas of the 'exciton' model. The analysis of natural alpha radioactivity is then extended to all known alpha -decaying nuclei, in order to obtain the value of the alpha -cluster preformation coefficient.