Differences in fundamental reaction mechanisms between high and low-LET in recent advancements and applications of ionizing radiation

• Recent applications of high-LET radiation include boron neutron capture therapy.
• UV treatment of electron-irradiated UHMWPE impedes degradation caused by allyl radicals.
• Radiation synthesis of PVP nanogels above 55 °C leads to intra-molecular crosslinking.
• PCBs in contaminated sediments can be dechlorinated by reactions with hydrated electrons.

Differences among the mechanisms of energy deposition by high-linear energy transfer (LET) radiation, consisting of neutrons, protons, alpha particles, and heavy ions on one hand, and low-LET radiation, exemplified by electron beam and gamma radiation on the other, are utilized in the selection of types of radiation used for specific applications. Thus, high-LET radiation is used for modification of carbon nanotubes, ion track grafting, and the synthesis of membranes and nanowires, as well as for characterization of materials by means of neutron scattering. Recent applications of low-LET irradiation include minimization of radiolytic degradation upon sterilization of ultra-high molecular weight polyethylene (UHMWPE), radiolytic synthesis of nanogels for drug delivery systems, grafting of polymers in the synthesis of adsorbents for uranium from seawater, and reductive remediation of PCBs.1