Systematic measurements of lineal energy distributions of various energetic heavy ion beams using a wall-less tissue equivalent proportional counter

Tsuda, Shuichi  ; Sato, Tatsuhiko   ; Watanabe, Ritsuko; Takada, Masashi*

Deposit energy distribution in a microscopic site is basic information for understanding of biological effects of energetic heavy ion beams. To estimate relative biological effectiveness, RBE, lineal energy, y, is used in simulation models as a physical index because y can treat each energy deposition in a microdosimetric scale by a single event of both incident primary heavy ions and secondary particles. In the present work, using a wall-less tissue equivalent proportional counter, y distributions, yf(y), have been measured for various energetic heavy ions of H, He, C, Si and Fe, and compared with results by simulation codes. The results of yf(y) distributions obtained using a narrow-shape beam and radial dependence of yf(y) distributions will be also shown in the presentation, along with the calculation results by the PHITS code and a track structure simulation code TRACION.