LET dependence on the dose response of the polymer gel dosimeter based on radiation-crosslinked hydroxypropyl cellulose gel

Hiroki, Akihiro; Yamashita, Shinichi*; Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

Polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate, polyethylene glycol dimethacrylate, and tetrakis (hydroxymethyl) phosphoniumu chloride with radiation-crosslinked hydroxypropyl cellulose gel were prepared. The prepared dosimeters were irradiated with 150 MeV/u He ions, 290 MeV/u C ions, and 500 MeV/u Fe ions at HIMAC, in which a linear energy transfer (LET) of He, C, and Fe ions were 2.2, 13, and 182 eV/nm, respectively. Absorbance of the irradiated dosimeters increased with an increase in the dose up to 10 Gy. The absorbance at total doses of 5 Gy decreased with increasing dose rate in all of the heavy ions. The dosimeter irradiated with Fe ions exhibited the lowest absorbance in these samples. It was found that the absorbance decreased with increasing dose rate as well as LET of the heavy ions.