The influence of antioxidant THPC on the properties of polymer gel dosimeter

In order to decrease the negative influence of oxygen to the response of PAG dosimeters THPC has been added to the gel in the role of scavenger. Apart from the decreased influence of oxygen, THPC also influences other properties of gel dosimeters. This study examines these influences and their quantification. Previous studies have shown that increasing the concentration of THPC causes a decreasing response of the dosimeter (as measured in the relaxation rate R2). Evaluation of the IR spectrum of gels irradiated by a variety of doses has shown that it is caused mostly by the changed structure of the arising polymer, not due to the decreased polymerization. THPC also changes the kinetics of the subsequent reactions in the gel after the end of irradiation. THPC has its influence also on the size of the dose response overshoot that happens in the areas of steep dose gradients. An easy model of action in the gel was suggested, which allows one to estimate the size and kinetics of the changed response of the dosimeter after the end of irradiation depending on the content of THPC, the size of the dose and the dose gradient.