Proton-Induced Giant Halos in Mica from Inclusions Containing Water

Inclusions in mica which contain $\alpha$ emitters together with some water produce long-range protons via the scattering reaction ${}_{}{}^1{}_{}{}^{}\mathrm{H}(\alpha , \alpha )p$. It is shown that the radial dependence of the proton ionization density can account for the giant halos which have recently been the subject of searches for superheavy elements.