Does multiple ionization intervene for the production of HO2 radicals in high-LET liquid water radiolysis?

In this work, we have described the various mechanisms suggested so far to interpret the large HO 2 yields observed in liquid water irradiated with radiation of high linear energy transfer (LET). The difficulties in interpreting these data have led us to postulate a new hypothesis where the role of multiple ionization of water molecules under high-LET conditions is invoked. Systematic experiments as well as an extension of the theory are needed to further clarify the precise extent of this mechanism.