[12p-N221-1~11] 2.1 Detection Devices

[12p-N221-1] Development of SiC semiconductor-based dosimeter for the evaluation of relative biological effectiveness distribution in the clinical carbon therapy field

〇Kohei Yamaguchi¹, Kei Kubodera¹, Rio Yanagisawa¹, Ryo Yokota¹, Makoto Sakai², Akihiko Matsumura², Takahiro Makino³, Takesi Ohshima³, Wataru Kada¹ (1.Gunma Univ., 2.GHMC, 3.QST)

Keywords:SiC, dosimeter, heavy-ion cancer therapy

Differences in linear energy transfer (LET) are expected to affect radiation assurance and control (QA/QC) in the heavy-ion cancer therapy field, where newly developed irradiation techniques such as multi-ion irradiation are expected to be installed. Conventional physical dose distribution measured by an ionization chamber is not sensitive for the differences in LETs. Thus it is necessary to develop a new dosimeter for better QA/QC. In this study, we have developed a dosimeter using a SiC Schottky barrier diode (SBD), which has excellent radiation tolerance with high energy resolution. Developed SiC-SBD was irradiated with a clinical carbon beam of 290 MeV/n 12-C at GHMC. SiC SBD was placed under a water tank with variable water thickness so that the LET spectrum of carbon beam was measured by SiC-SBD at each point of the Bragg curve by changing the water thickness. The water-equivalent LET distribution at each depth was estimated by utilizing the stopping power ratio of SiC and water. The distribution of RBE-10 was also able to be calculated using water-equivalent LET distribution. It was confirmed from the experimental results that SiC-SBDs could be utilized to estimate and evaluate the LET and RBE-10 distribution at the clinical carbon beam field.