Inhomogeneous kinetics in the quenching of prompt radioluminescence: Analysis of alpha particle and proton induced fluorescence decay curves

Fluorescence decay curves for dilute solutions of benzene in cyclohexane excited by pulsed proton and alpha particle irradiation are analyzed in terms of a spur diffusion model. This model predicts a reduction in the quenching of fluorescence induced by alpha particles relative to that observed with proton irradiation of the same stopping power due to the more diffuse radial distribution of energy deposited by the higher velocity ion. However, to explain the observed reduction in quenching with alpha particle irradiation on the basis of this model requires a mean spur energy significantly smaller than that used to explain related phenomena in the radiation chemistry of aqueous media