Revision of the Model of Formation of Radiolytic Products in Aqueous Solutions

Positronium formation in a liquid phase: Influence of intratrack reactions and temperature

“…A list of the most important primary reactions has been given in a number of previous publications [3,6,7]. The values of the diffusion coefficients D i and reaction rate coefficients, k ij , between species of i-and j-types are known at the nanosecond stage.…”

Influence of Temperature on Intratrack Processes and Ps Formation and Behaviour in Liquid Water

“…The values of the reaction rate constants, k ij , between species of i-and j-types at nanosecond stage are known, but their values at picosecond stage were estimated by fitting a wealth of kinetic data relating to the main radiolytic products. Reference is made to our previous work concerning these values and those for the diffusion coefficients [1,3].…”

“…In this work we describe the intratrack reactions as previously [1,3], adding new assumptions concerning the T-dependence of k ij . Since the chemical reactions at nanosecond stage are diffusion controlled, it is reasonable to consider that the rate constants obeys the Stokes-Einstein relation:…”

Ps formation in molecular media: low temperature hydrocarbons

“…It is commonly accepted that in homogineous molecular media Ps forms in the terminal part of the fast positron track 1 in combination with one of the knocked out thermalized track electron: e + + e − → Ps [5][6][7]. This reaction competes with other intratrack reactions (ion-electron recombination, electron localization, out-diffusion etc.…”

“…J is the production rate of primary ionelectron pairs per unit volume 2 , f t is the probability of the track electron to survive in intratrack reactions and escape out of its track, κ = 1/(1+k re τ t C R ) is the probability that this electron escapes further capture 1 The end part of the e + (or e − ) track is usually called as blob. 2 In case of irradiation by the e + source J equals to the intensity of the source (0.15 MBq) multiplied by the average initial energy of the positrons (∼200 keV, for 22 Na), divided by the formation energy of one ion-electron pair (∼20 eV) and divided by the average volume, where positrons stop (∼0.1 cm 3 ).…”