Extension of PHITS track structure calculation mode

Ogawa, Tatsuhiko   ; Kai, Takeshi   ; Hirata, Yuho   ; Matsuya, Yusuke  

Track structure calculation is a technique to predict energy deposition in sub-micro meter to nano meter scale by tracking electrons down to a few eVs. Conventional track structure calculation codes predict electron transport using the cross section of target materials calculated based on dielectric functions, in other words, response to electro-magnetic waves. Owing to this procedure, they are applicable merely to materials whose dielectric function is measured in a wide frequency range. Therefore in this study, a track structure mode is developed by using stopping power formula and secondary electron energy distribution systematics. In this study, stopping power and secondary electron energy were calculated by ATIMA and Rudd's formula, respectively. Stopping range, radial dose distribution, and stochastic energy deposition distribution calculated by our code agreed well with literature data indicating validity of our model. This model is going to be implemented to the next release of PHITS to be used by users.