  In this paper we present all-order quantum mechanical calculations of 7Be
breakup on heavy (208Pb) and light (12C) targets. We examine the issues
concerning the extraction of the astrophysical S-factor from the breakup data.
We discuss the interplay between Coulomb and nuclear breakup, and the
importance of higher-order couplings on the cross section. We show that nuclear
and Coulomb contributions are not separable using the standard angular
selection criterion as nuclear breakup remains large for small scattering
angles, even for the heavy target. However, by selecting an upper limit on the
relative energy between the final fragments, the contribution from the nuclear
breakup can be significantly reduced such that Coulomb breakup is the main
reaction mechanism. We show that the extraction of the asymptotic normalization
coefficient may require more careful consideration of the nuclear interior than
previously used.
