Harris, R. E. and Pimblott, S. M. On ³H β-Particle and ⁶⁰Co γ Irradiation of Aqueous Systems. Radiat. Res. 158, 493–504 (2002).

The chemistry of water and aqueous solutions is very different after irradiation with ³H β particles and high-energy electrons or ⁶⁰Co γ rays. The greater the linear energy transfer (LET) of the medium for ³H β particles compared to high-energy electrons or ⁶⁰Co γ rays leads to an increased local concentration of reactants. There is an increased amount of intratrack chemistry, which reduces the escape yield of e_aq⁻ and OH by about 50%, but increases the yield of H₂ by about 50% and of H₂O₂ by about 35%. Analysis of stochastic-diffusion kinetic calculations employing simulated track structures reveals that the yield of H₂ produced by diffusion-kinetic processes increases significantly for ³H β particles compared to ⁶⁰Co γ radiation, while production of H₂ by sub-picosecond processes is essentially the same. In both ³H β-particle and ⁶⁰Co γ radiolysis, the reactions (e_aq⁻ e_aq⁻) and (e_aq⁻ H) are equally important in the production of H₂. In the former case, each reaction has a yield of ∼0.18, and in the latter a yield of ∼0.08. In neutral water, the reaction (H H) is negligible. The yield of Fe(III) in ³H β-particle radiolysis of the Fricke dosimeter is much smaller than in radiolysis with more energetic electrons. Simulations show that this change is primarily due to the reduced escape yield of H, formed from the scavenging of e_aq⁻ by the bulk H₃O of the acid. The chemical differences observed in experiments, and in calculations, reflect the underlying structure of the electron tracks: Examination of the track structure simulations demonstrates that primary events are considerably more well-separated in high-energy electron tracks compared to ³H β-particle tracks.