Development of polymer gel dosimeter based on hydroxypropycellulose hydrogel; Effects of solute compositions on dose response for -irradiations in terms of turbidity

Yamashita, Shinichi; Hiroki, Akihiro; Nagasawa, Naotsugu; Taguchi, Mitsumasa

Polymer gel dosimeters based on hydroxypropylcellulose (HPC) hydrogel crosslinked by an irradiation of 2-MeV electron beam have been developed. Gel properties of the radiation-crosslinked HPC hydrogel were estimated with varying HPC concentration, absorbed dose, and type of radiation. Such hydrogel was utilized as gel matrix for polymer gel dosimeters which are more environment-friendly and easily handled than "toxic" polymer gel dosimeters composed of methacrylic acid or acrylamide. In the present study, solutes of the gel dosimeters were 2-hydroxyethyl-methacrylate (HEMA), polyethylene glycol dimethacrylate (PEG), and tetrakis hydroxyphosphonium chloride (THPC). Ratio of the concentrations of the solutes was varied to investigate sensitivity from the viewpoint of absorbance in a UV-vis region. As a result, absorbance increase in shorter-wavelength region (i.e. 300-500 nm) was different from that in longer-wavelength region. It was found that a peak appears in 300-400 nm with about 4-Gy irradiation, which is thought to be corresponding to productions of microgels, and that this peak slightly shift to longer wavelength with further irradiation.